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Water Sampling - Science topic

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Hi there! As I understand it, it is standard practice to acidify filtered water samples down to less than pH 2 before introduction to ICP (for metals analysis). The main rationale for this is repeatedly stated to be "keeping metals of interest in solution". I am wondering, however, how useful the dissolved metals concentrations that result from these ICP analyses really are, considering that the analysis conditions are obviously far different from those of ambient waters (which are not at a pH of 2!). Wouldn't this result in a major overestimation of the concentration of dissolved metals in the ambient environment?
Hope to get a conversation going about this. Thank you!
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Adam has made important points. I would add only that the international operational definition of 'in solution' is 'passing 0.45 microns'. So if you want to make comparisons that must be done. What more realistic measures you make is up to you.
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Dear Botanists and ecologists!
Attached picture represents a submered plant species of freshwater Himalayan lakes occurring at an altitude of 1800-2000 meters. The plant survives under water. The leaves turn yellow and die within a day or two if kept outside water sample.
Please help me identify at least genus of this plant!?
Thanks in advance!?
#botany #submerged #plants #lake
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It is difficult to identify a plant without reproductive structures such as flowers and fruits.
Thanks!
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I have recently isolated  presumptive pseudomonas aeruginosa from a pool water sample using membrane filtration on Pseudomonas CN agar. This was set up to be confirmed using CMA agar and nutrient agar. Results came back were oxidase positive, casein hydrolysis positive and colonies appeared pigmented. However no fluorescence was observed under UV light.
I was just wondering if without performing further tests would anyone would say this was confirmed as pseudomonas aeruginosa or is fluorescence a requirement?
Thanks
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Why pseudomonas emit fluorescens???
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I have been analyzing water samples on a spectrophotometer and the readings are in mg/L and I need to change them into micromoles per liter.
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mg/L divided by 1000 is g/L.
g/L divided by the molecular mass in g/mole is mole/L.
mole/L x 1,000,000 is µmole/L.
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can anyone guide me about the determination of 4-methylimidazole in the beverage industry sewerage water sample/
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DOI: 10.1007/s10337-012-2362-x
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Please give some suggestion
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if the question is are there effects the answer is yes there are. - changed evaporation of the metals and decreased lfietime of the graphite furnace e.g.
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In our current job we are collecting water samples from a river and the purpose is to sequence all the microbiome. So, aside from membrane filtering, which other methods (without causing damage to the DNA) can we use to concentrate the microorganisms from this samples?
For example, I was wondering if I can agglutinate them?
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Use 0.22 or 0.45μm filter paper for suction filtration, then use sterile normal saline or phosphoric acid buffer to elute the collected material to the beaker, and then transfer it to the centrifuge tube for centrifugation with a high-speed centrifuge
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I need basic parameters such as pH, temperature, COD and BOD and coliforms.
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Typically water quality sampling has several approaches. Some are just reconnaissance or trend sampling. Others seek to determine the effects of some activity, or the location of a likely problem such as point or nonpoint pollution sources. Since water quality can vary substantially with time and flow rate, some researchers use aquatic macroinvertebrate sampling to help parse out areas within a basin which are dominated by organisms tolerant of pollution as potential problems to explore. Because aquatic insects can be found almost anytime, they can be good indicators of water quality. Some studies use identified point sources and land use surveys to help estimate problems that are worth better definition and quantification.
Another issue might be the term basin. Some use it to define a very large hydrologic unit, and others might use the term to define a very small catchment. In the USA, the USGS uses basin as very large hydrologic unit. The USGS samples some of these basins for water quality, and their data can be found on the internet at usgs.gov. Water sampling is costly however, so likely most of their sampling has some purpose, or some sites may be continuation of long term trends once a site has been instrumented.
You might find a couple of my researchgate entries interesting in your search for examples. Typical sampling approaches are above and below pollution, and much difficulty enters when sampling larger streams and rivers, as it takes time for the pollutants to mix and selecting a site too close or too distant can become problematic to your analysis. Another importance to consider is access to the monitoring site(s), and some samples may need to be kept cold until reaching the lab, so ready access is a plus such near a bridge, trail crossing, etc. Some tests might be run in the field, and recording water temperature may be possible with relatively small recording devices installed into the stream. But when measuring temperature in a river, you need to avoid locations such as being below a small tributary which may have much cooler or warmer temperatures. Large rivers common to USGS basin size hydrologic units are not easily sampled for water quality because they are so large, often not wadable, and may require proportional sampling across the river cross section, with samples taken perhaps from a bridge.
It would be good to develop a sampling or monitoring plan, and have it reviewed by a hydrologist or water quality professional, professor, water lab professional, etc. A statistician may also be helpful if you want to publish or use the data to solve a question or document a situation that may lead to court action. The work can be complicated, costly, frustrating and possibly wasteful, if the design and reasoning for the sampling activity are not carefully considered. For research, best to use Standard Methods for Analysis of Water and Wastewater Quality.
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Dear all,
Can you please explain me with your experiences why there is an increase in Dissolved Organic Carbon / Total Organic Carbon after treating my water samples with oxidants like Chlorine and Ozone. I am giving a reaction time of 15 minutes and then quenching my excess oxidants (Ozone - Nitrogen gas, Chlorine - Sodium thiosulfate).
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Hello Guhankumar Ponnusamy,
Did you find an answer to your question?
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Hello i want a method to determine nitrate in water samples without a device otherthan spectrophoto meter???
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Three different methods for nitrate determination in environmental samples were comparatively examined.
1. From the data obtained it is concluded that the cadmium reduction method is the most suitable for every type of environmental water samples.
2. on the contrary, the electrode screening method suffers from many interferences and is not suitable for any type of sample.
3. The direct spectrophotometric method has been found to be applicable mostly for fresh water samples
Nitrate Testing Procedure 1. Fill the sample bottle with sample water. Use gloves if drawing the sample by hand. 2. Rinse and fill one test tube to the 2.5 mL line with water from the sample bottle. 3. Dilute to the 5 mL line with the Mixed Acid Reagent. Cap and mix. Wait 2 minutes. 4. Use the 0.1 g spoon to add one level measure (avoid any 50-60 times in one minute). Wait 10 minutes. 5. Insert the test tube into the Nitrate Nitrogen Comparator. Match the sample color to a color standard. Record the result as mg/L(ppm) Nitrate Nitrogen (NO3-N). To convert to mg/Nitrate (NO3) multiply by 4.4. 6. Place the reacted sample in a clearly marked container. Arrangements should be made with toxic material handlers for safe disposal. Please wash your hands after this water test is completed..
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Need 0.5-1000ng/ml sensitivity. Any experience? Brands to use?
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See the following papers by our Univ Colleagues
and
Kinoshita, M., Zakaria, M. P., Ismail, A., Yusof, S., Boonphakdee, C., Boonphakdee, T., & Inoue, K. (2010). An attempt to detect contamination with estrogenic compounds in river water of urban area in Thailand and Malaysia using transgenic medaka. J. Coast. Mar. ScI, 34(1), 216-222.
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We intend to analyze Hg levels in seawater samples. According to the literature, Hg concentrations in water samples may be lower than in sediment. As a result, we will be able to obtain more accurate results if we can concentrate the water samples prior to analysis.
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Not a device but a method as Dan explained.
An alterative method is to transfer a known volume of water sample to a ground glass stoppered flask (or other suitable closed container.) Digest the sample with dilute potassium permanganate/potassium persulfate solution, and oxidize for two hours at 95°C. The mercury in the digested water sample can then be reduced using stannous chloride, which converts it into elemental mercury. Analysis can then be undertaken using conventional cold vapour atomic absorption.
Information about other methods are available on the internet.
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PL of Water Samples were recorded at SAIF-SPIHER by using PerkinElmer LS 45 Photo Luminescence spectrometer.
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dear colleague
i think that we can not speak about PL in case of water that is a liquid. We generally evoke it in semiconductors and insulators material. Nevertheless, if you mention your exciting wavelength we can can more discuss (may be you need more experiments to determine exactly the identity of your results)
regards
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I am studying the occurrence of microplastics in a river, where the sampling site is too much plastic polluted. Therefore, I have found a high concentration of microplastics in water samples. I am wondering to know the possible highest concentration of microplastics in a polluted water sample which has been recorded till present. It will be helpful for me if anyone suggest me any scientific paper regarding this or any comments on this. Thanks a lot for your time.
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Although it is not possible to know the exact contamination aspect of microplastics, it has been continuously reported to be detected in seawater, fresh water, food, air, and soil. Moreover, it is predicted that the contamination of microplastics will become more serious in the future by several studies. A global estimate of plastic emissions from rivers into the world’s oceans is between 1.15 and 2.41 million tons per year, and most of the river plastic input is coming from Asian countries with rapid economic development and poor waste management [29]. The concentration of microplastics was 250 mg/m3 in 2016 and is expected to be 500 mg/m3 in 2030, and probably exceed 1000 mg/m3, which is four times the 2016 amount, by 2060.
Please refer to the following interesting papers:
Avio, C.G.; Gorbi, S.; Regoli, F. Plastics and microplastics in the oceans: From emerging pollutants to emerged threat. Mar. Environ. Res. 2017, 128, 2–11. [Google Scholar] [CrossRef] [PubMed]
Isobe, A.; Iwasaki, S.; Uchida, K.; Tokai, T. Abundance of non-conservative microplastics in the upper ocean from 1957 to 2066. Nat. Commun. 2019, 10, 417. [Google Scholar] [CrossRef]
Kim, H.J.; Lee, J.Y. Emerging Concerns about Microplastic Pollution on Groundwater in South Korea. Sustainability 2020, 12, 5275. [Google Scholar] [CrossRef]
Lebreton, L.C.M.; van der Zwet, J.; Damsteeg, J.-W.; Slat, B.; Andrady, A.; Reisser, J. River plastic emissions to the world’s oceans. Nat. Commun. 2017, 8, 15611. [Google Scholar] [CrossRef]
Regards
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Dear limnologists - marine scientists
I am looking for a sampler that can collect integrated water samples in the 0-20m depth range.
In our lab we have an old, mechanical Schröder bottle which unfortunately stopped working and may no longer be repaired. We'd prefer to replace it with an equally simple, mechanical device, but I'm having a hard time finding one.
Do you have any suggestions?
Thank you in advance,
F. Lepori
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We have water samples from clean river that need to be tested for anion. However, the machine is currently not functional for a moment. Is there a technique to preserve the sample without using separate technique as I being told that separate method of preservation for each individual anion to be tested.
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I have a follow-up question, why acid is not added to preserve anion testing in water samples? I know it helps to "The addition of acid can greatly inhibit or prevent the
metabolic processes of microorganisms which cause
changes in the sample. Furthermore, it prevents flocculation
and precipitation, for example, metal compounds
and reduces adsorption on the surface of the container."(water research vol 15)
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I want to measure the particulate organic carbon in water sample. Anybody know any institutes or laboratories that provide these services for outside samples.
Thanks in advance
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Please check out CSIR–CLRI located in Chennai.
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The essential step in solving a water quality problem is to obtain a reliable water sample and analysis
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Self realisation and awareness about the importance of water and its quality is main to solve the problem.
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Extraction of pesticides using modified QuEChERs method for fruits, food, vegetables and other oil samples the recoveries are not achieved at the spiked concentration levels ?
Same issue in water samples ?
Pesticides getting degrading/converting all isomers together and giving higher concentration ?
Not all I faced some compounds in GC-MS/MS
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For acidic compounds a possible explanation for the low recoveries of the use of PSA. This adsorbent, a primary and secondary amine, can interact with acidic compounds
yielding low recoveries after the clean-up step.
In addition, some compounds are a troublesome
compounds for GC–MS analysis because of their thermal degradation. Moreover, it is reported that
chlorothalonil presents recovery problems in some matrices when extracted with acetonitrile.
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I need to get information on the morphology of soil colloid particles in water samples. Can I use water samples (filtered through 1 micron) for scanning electron microscopy or they need to be dried?
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The process is carried out high vacuum...hence any thing loose will not stay there...other thing topographic feature of material remains observable if the surface is static...so liquids are not studies as such...solidified material are also Studied with special arrangements and set of device...commonly this is not possible.
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The procedures for digestion of a river water sample for chemical analysis
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You should provide more details. The choice of the method of preparing river water samples for spectrometric measurements depends on the following conditions and the measuring and auxiliary equipment available. Should the object of analysis be water including suspension or do you also need separate results for the filtrate? Which elements are you interested in and what detection and quantification limits for each element do you need to achieve? What AAS techniques do you have at your disposal? Only FAAS, or also GFAAS, HGAAS? Which spectrometer model do you have (manufacturer, type)? Are you an experienced AAS spectrometer user or rather a beginner?
In general, the most useful information, guidelines and methodological recommendations can be found in information and training materials available on the websites of spectrometer manufacturers and in various publications of official, professional and scientific institutions dealing with environmental research, in particular surface and ground waters. If you are a beginner in the AAS technique, a training stay in a specialized laboratory, equipped with a spectrometer technically similar to your spectrometer will be the best for you.
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Hello everyone, can anyone tell me the correct procedure that it is essential to do the microwave dilution in the ICP to check the copper in the water?
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Analytical task:
Determination of Cu in water samples
What do you mean "microwave dilution of water samples?"
There is no need to digest the water samples.
The first step is Sampling
Sampling
Polyethylene bottes have to use for all water samples .All samples for trace analysis must filtrate through membrane filters (0.45-μm micropore) and conserved with HNO3 with concentration from 0. 5 % to 2 % in accordance
with ISO 5667-1, 1980 - Water quality — Sampling —standard requirements
Calibration procedure
The reference solutions for the determination of Cu in water samples
were prepared by using Merck ICP-AES mono-element standard solutions in the presence of 1 mol l-1 HNO3.
Acid blank (1 mol l-1 HNO3) was prepared for measurement of the background signal in λa of the selected prominent line of Cu.
With kind regards, N.Daskalova
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I have digested 30mL of water in H2SO2 and the final volume is 100. After taking 5ml for distillation, the titration volume with HCL 0.01N for water sample was 1.7mL and for blank was 0.1mL.
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Kjeldahl nitrogen that method
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if we are having water with pH = 11.5 , this water containing calcium, Magnesium, silicate chloride , sodium, Sulphate and other elements. How can I measure or calculate NaOH concentration in water sample
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You will visualise different slopes when you perform the potentiometry.
The stipest should belong to NaOH. I am assuming it is the predominant species.
Calcium and Magnesium maybe could interfere. You could try a complexation with EDTA first.
If you have it available, with Atomic Absorption spectrometry you could quantify the quantities of the different cations present.
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Probiotics and Therapeutic effects of lactic acid bacteria isolated from freshly harvested fish and water samples against wound-borne pathogens. I need an expert advise now . Thanks
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U want to isolate the same bacterial strains from the fish and water?
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Should we convert our data from mg/L into meq/L to calculate the Saturation index for water samples? I am using Phreeqc software.
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Dear Arif,
You may input alkalinity values in meq/L or mg/L (as CaCO3) (Alk. in mg/L as CaCO3 = 50.05 X Alk. in meq/L). Also, if you have HCO3- and CO32- concentrations, you can also input those instead of alkalinity.
Regards
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-The atomic radius of lanthanum is approximately 0.35 nm, as opposed to 0.3 nm for water molecules.
-Seawater sample also contain organic contaminants such as Mg, Na, etc. some of them with the same molecular size as lanthanum.
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Adsorption
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Dilution factor is necessary for analysis of water samples by ICP-MS  with high  total amount of dissolved solids (TDS).
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Hi Farideh Amini Birami . The dilution factor = volume taken / total volume .
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I have tested drinking water sample with (total count, pseudomonas aeruginosa, T.Coliform and fecal strepto.)
I found that the M.edno LES AGAR have growth but the others no one colony, even the nutritive media (plate count agar)
so what kind of enteric bacteria that can growth only on M.Endo LES agar but not in the others ?
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Our water sample contains organics and sulfide S2-, is there a way to quantitatively measure the organics content in general avoiding the interference of H2S? e.g. TOC/COD?
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You may acidify the sample, strip out the H2S before COD measurement by open reflux.
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I am trying to refine a density separation method for quantifying the mass of microplastics in a water sample. I am encountering a persistent problem of recovering excess weight in all my spike samples, including in my method blanks. I know that ZnCl2 can precipitate zinc oxychlorides at higher pHs, so I have used acidic DI water (pH = 2) to rinse ZnCl2 through the filter during vacuum filtration. This has reduced the excess mass recovery, but I am still recovering 2-10 mg of excess mass, even in method blanks. This persistent bias is a problem because I expect the mass of the samples I hope to analyze is in mg. Does anyone have recommendations for improving the precision of density separation methods with ZnCl2?
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Hi Chelsea. We had issues with high amounts of precipitates on our filters after high density salt separations. Could you you rinse the filters with DI water to help remove some of the salts from the particles? We follow our filtrations with DI water wash steps to help remove excess salt.
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I just need the equipment or materials that is used for water sampling as it is required for my group to conduct.
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Gloves, wash bottle, alcohol, ice chest, thermometer, gps machines can be used
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I added jaggery and fermented it in water. I would like to know the quantification of alcohol. What are the methods that can be used for the quantification?
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You can check quantity of alcohol by HPLC and its purity by GC method.
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Hello,
I am using an ICP-OES for elemental determination for waste water samples. The procedure is to digest 100 mL of the waste water with 2 mL HNO3 + 1 mL HCl, until the volume is reduced to 20 mL. Then the solution will be diluted with ultra pure water to 50 mL and this solution will be measured for elemental determination on an ICP-OES.
How can I calculate the dilution factor in that case? And as an example, Cu = 300 ppb (measured), what will be the initial concentration in the waste water sample.
In advance, thank you very much for your help.
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I concur with Junhang Dong 's explanation
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Let's say I am testing for fluoride in a water sample. I diluted the sample 10 times by making 10ml of sample into 100ml. I take absorbance of this diluted sample using UV-Vis. So, my doubt is, Should I multiply the absorbance value by 10 first and calculate the concentration or calculate the concentration first and then multiply it by 10? Where should I incorporate this dilution factor?
Thanks in advance!
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Hi Auchitya Verma , when you calculate the concentration of any substrate in the initial sample, you need first to know its concentration in the diluted sample (instrument value).
According to the formula C1*V1=C2*V2, the dilution factor equals DF=C1/C2=V2/V1
where C1 is the starting concentration (of the initial sample), V1 is the starting volume (of the initial sample), C2 is the final concentration (instrument value), and V2 is the final volume.
For calculating C1 according to the above-cited formula, we can write:
C1=C2*V2/V1
or
C1=C2*DF
So, you can see that to calculate C1 we need first to know the instrument value C2 then multiply it by DF value.
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Hai,
Please help!!
I am doing a study on REE in some rivers.
To find the relative enrichment of LREE or HREE how should I do.
I did the normal calculation of Sum of LREE/sum of HREE and if the value is greater than 1 it LREE enrichment and Less than 1 HREE. However, I did this simple calculation in the Obtained concentration of data from ICP-MS and I am getting a High LREE enrichment.
The problem I am facing is this is not the case for a normalized pattern where if I do the above calculation it shows HREE enrichment and also the spider plot show the same. I also did some other ratio calculations with normalized data all showing HREE enrichment.
Which should I follow? the normalized data or non-normalized data to find the REE Enrichment of my water samples.
It would also be a kind gesture if anyone can provide me with the equation to calculate the REE enrichment for example for (La/Lu)PAAS.
thank you for your kind consideration
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Perhaps you could look in the topic section: 150 questions with answers in RARE EARTH ELEMENTS | Science topic (researchgate.net)https://www.researchgate.net/topic/Rare-Earth-Elements
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I am developing research for microbubble ozonation of pharmaceuticals in water treatment. My previous research uses the centrifugal-water pump with a vortex diffuser to generate the microbubble. This system needs extra energy and a large number of water samples. I am looking for a microbubble generator that could be used in the 1-2 L ozonation reactor size.
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Hello,
I am detecting the presence of intl1 genes in Klebsiella bacteria and the PCR product is shown in the image below.
the expected pcr product size is 254 bp. I’ve added positive and negative control samples (tested previously) and a water sample (to detect any contamination).
The pcr is showing both bright and faint bands, I’ve loaded equal amounts of each sample (10 microliters in a 150 ml of 1% agarose gel). Is this contamination? Why is the water (the supposedly DNA free sample) is showing brighter bands than the DNA-containing samples?
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That is probably because of contamination.
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I have taken a water sample from point that pass trough two new water cartridge with filter 0.45 & 0.2 micron, so it's seem to be sterile !
and filtrated it with 0.45 Millipore filter, after incubation I found the sample is very crowded with colonies, knowing that the source is very crowded also with bacteria.
Does the high load of bacteria can pass throw the filter cartridges ?
AND WHY PASS throw the cartridge but not in the (0.45 Millipore filter)?
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Bacillus subtilis, Staphylococcus aureus, Klebsiella pneumoniae, and Escherichia coli passed through a 0.45-µm pore size filter within 48–96 h. Pseudomonas aeruginosa, Serratia marcescens, and Listeria monocytogenes passed through a 0.3-µm pore size filter.
abstract
Bacteria growing on MF-Millipore filters (thickness, 150 micro m) passed through the underlying membrane by their infiltration activity. Bacillus subtilis, Staphylococcus aureus, Klebsiella pneumoniae, and Escherichia coli passed through a 0.45- micro m pore size filter within 48-96 h. Pseudomonas aeruginosa, Serratia marcescens, and Listeria monocytogenes passed through a 0.3- micro m pore size filter. P. aeruginosa passed through a 0.22- micro m pore size filter. The membranes which allowed passing-through of bacteria showed normal bubble point values in the integrity test. Studies with isogenic S. marcescens mutants indicated that flagellum-dependent motility or surface-active exolipid were important in the passing-through. P. aeruginosa PAO1 C strain defective in twitching motility was unable to pass through the 0.22- micro m filter. Scanning electron microscopy showed bacteria passing-through the 0.22- micro m filter. Millipore membrane filters having well-defined reticulate structures will be useful in the study of infiltration activity of microbes
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If drinking water samples for trace metal are not able to be filtered and acidified in the field but are kept below 4 °C and delivered to the lab in under 24 hours, can they still be considered safe or representative ?
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J. Hunter Adams thank you for asking. I am concerned about the integrity of the water samples as the location of the water samples is in a rugged terrain and transporting the samples immediately to the laboratory might not be possible.
I have decided I will filter and acidify the water samples for trace metals out in the field.
For your question regarding what method I am using, if your referring to the sampling method, I have adapted the water sampling method from FOREGS Geochemical Mapping Field Manual (1998).
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This is my first time of collecting water samples from marine environment. Could somebody please tell me the technique? I mean what kind of equipments (I usually used plankton net for freshwater) and procedures, in terms of collecting samples for metagenomic analyses. I could read from articles (and I did) but I need more practical quidance. Thanks a lot!
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Younes Boundir thank, but I can't read French
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Hello,
I need to determine the total sediment concentration in g/L in some water samples. I have never worked with sediments before and wanted to ask what type of filter (polycarbonate or glassfiber) you all would recommend.
I would ideally like to have a retention of .45 microns for fine clays and would like to burn off the organics (I was thinking 4hrs at 400degC?). I was hoping to be able to use the GF/F filters we have around the lab but they only have a 0.7 micron retention size.
Thanks!
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Dear Astrid, I would evaporate the water from a known quantity of sample so as to obtain the total clay content. Remember that heating samples containing organic matter and certain clay minerals results in their partial or complete decomposition, e. g., montmorillonite at 250 degrees C. Organic matter can dcompose at well below 80 degrees C. which creates problems with peats..
Stuart.
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I have found unusual highly saline geothermal groundwater samples in granite reservoir and the sodium and chloride composition of that sample are very high as compare to other water samples of surrounding areas. The sampling area is almost 80 kilometre away from the sea. How I can know whether the salinity of water samples is due to the mixing of ancient trapped sea water or not?
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Create a mathematical model of the found mixture and analyze the numerical solutions by drawing a differential scheme with approximation. Maybe you will have the solutions you need!
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Hello everyone,
It will be correct to analyze a pool water sample for coliforms with the MPN technique of the Standard Methods with a series of 10 tubes and not a series of 5 tubes, because normally potable water is processed with a series of 10 tubes and non-potable water with a 5 tube series.
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Comme les autres eaux
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Water samples are planned to be collected in non-light transparent bottles with tight caps and we plan to preserve with hydrochloric acid and will be transported in an ice box for laboratory analysis.
We need concentration?
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2% HCl or HNO3 should be fine. It is said that we add acid to bring the pH to 2 which requires few drops of concentrated acid (HNO3 or HCl). The idea behind adding the acid is to cease microbial activities.
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Isolation of protozoans from water samples
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Check the article below about your subject.
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Performed GC/MS/MS without derivatization and found Epitestosterone, tert-butyldimethylsilyl ether, Pregnenolone,3-trifluoroacetate, Pregnenolone,3,2,1-bis(trimethylsilyl)oxyl-3(beta), Pregnenolone,3(acetyloxy)-cyclic 20-(1,2-ethanediylacetal) (3-beta) and phthalic acid, 2,6-dimethoxy phenyl methyl in my water samples? I am looking for what could be the possible reasons and did the compounds form bonds with esters to have the above resultant compounds?
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Thank you, Ulrich
I hope you are healthy and Safe
Likewise, you did mention your work on the soil, how were you able to trace for the degradation products with its parent compound. How could we prevent the silyl component in our compounds?
Looking forward to hearing from you
Thank you
Regards Mehak
Stay Safe
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Hi,
I am working on microplastic contamination in the water samples, and I have prepared the samples as per NOAA. Still, when analyzed using FTIR (Bruker - ATR mode), the transmittance spectrum is more than 100% (nearly 102 or 104). Please explain how to get rid of these and interpret the results?
I am attaching the raw spectra for reference
Thank you in advance
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J. Hunter Adams Sir,
is there any way to rectify the issue?
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how to isolate the indigenous microalgae from water sample
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Hope this handbook helps.
Please check Chapter 4 - Microalgae Isolation and Basic Culturing Techniques.
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Hi,
I expect a concentration of 5 mg/L of Nitrate ions in a deionized water sample, containing only one solute i.e. NaNO3. How many points should I take and what respective concentrations to determine the conc. of unknown sample using the calibration curve?
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We also use at least 5 points of a curve, of course you can use more than 5, in our nitrates method we use 6 points 0.5, 1,5,10,15,20, 30 mg / L, but we also use a control of quality of 10 mg / L (the nitrate ion of this control comes from a solution other than the curve) you could use a 5 mg / L with that you would corroborate the concentration you expect.
I hope to help you a little.
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I tested a water sample after collecting it from a wastewater treatment plant. The WWTP disinfects the water by using UV and then reaerates the samples. After that, they discharged the treated samples to the river. The collected sample is UV treated but not reaerated. I have got 2.2 mg/L ammonia-N in this sample. I think this is pretty much higher. I am planning to make potable reuse of this water. So what will be the probable causes for the presence of ammonia-N in this water? And also what are the effects of humans on the presence of ammonia-N in water? Thanks in advance.
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If the Ammonia is not removed it will 1) create a disinfection demand within the water treatment plant and 2) within the distribution system it will feed nitrifying bacteria that will convert it to Nitrate/Nitrite and the bacteria will lower the disinfectant and alkalinity within the water mains, in the process.
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I have water samples that have an unknown concentration of Na/K. I have taken a 5ml sample and added 5ml distilled water, then what will be the dilution factor and how I can find concentration by using df.
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I have a sample of treated water sample & asked to obtain ammonia conc. in sample using a machine with 5-25 ppm detection range. However, upon testing with different dilution factors, all calculated conc. shows different values (df 50 - 89.5 ppm & df 20 - 104.4 ppm). So, does using different dilution factors affect negatively on the values or there are other factors affecting those values ?
thank you for your time
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Muhammad Anas Yuzairi Mohd Yusri The linearity of the standard curve is important. When diluting samples always dilute them so that the readings fall in the mid range of the curve.
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I am a master student. Can anyone advice me on how can i conduct this research? Also how can i separate plastic from other particles from tap water sample?
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To identify microplastics, analytical techniques such as pyrolysis gas chromatography/mass spectrometry, Raman scattering, scanning electron microscopy, and Fourier-infrared spectrometry are usually used. Fourier-infrared spectrometry is the most common method, as noted above by colleagues
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As to assess the geothermal potential of a hydrothermal system, geo-chemical thermometers are well established. Among the various geochemical thermometers, the silica thermometer is very sensitive and widely used for determining the reservoir temperature of the geothermal system. The main input is dissolved silica in hot spring/ bore well waters. The quantity of the silica may vary from traces to hundred mg/lit.
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Dear Kumar,
I really appreciate for such an important question. I found really good comments in the responses.
Cheers,
Rahim
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I collected the water sample from pond and 1 ml of pond sample diluted with 9ml with water and 100 microliter was cultured into the MacConkey agar plates .Finally,80 colonies were formed in the plate .So, the CFU/ML 8000CFU/ML right???
From here,my question is how can i change these CFU/ML value into 100 CFU/ML and 10000 CFU/ML value....
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Getting lower CFU/ml is a relatively straightforward procedure (dillution with the adequate amount of a sterile, standard bacteriological dillution. When you want to concentrate the amount of cells in your sample, you can centrifuge it (preferably under refrigeration), discard the supernatant and suspend the pellet in the desired amount of a sterile, standard dilluent.
If you need to adjust the microbial concentration in your samples on a regular basis, you might want to correlate the CFU/ml with the OD/McFarland of the sample and use these easy, fast to perform measurements instead. Beware, however, these fast measurements are not extremely accurate.
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I was using autoclave for digesting water samples for Total phosphorus measurement with ascorbic acid method. The autoclave was set to perform 2 hours digestion and around 121 Celsius degrees. I only applied one drop phenol and 0.4 gram of ammonium persulfate to 50 ml water samples before digestion. However, sometimes I discover the water samples turned out become yellow in few bottles after digestion, but (so far) it never happened to standard solution which are digested at the same time. Anyone ever experience the same thing?
Thank you so much for your help.
:)
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I have low bacteria density in water samples. I thought to preconcentrate them by filtrating a known volume of water (e.g. 500 ml) in 0.2 um Nylon filters, and then suspended bacteria that has been retained in the filter by sonicating (30 seconds to avoid cell lysis) in 5 ml of Ringer. Do you think it would work? Does anyone have any other idea?
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Totally agree with above suggestion. In addition to that you can go for spread culture technique with lower dilution of the bacterial culture.
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We recently sampled produced water from oil wells and want to extract RNA and analyze it for microbial activity. Due to the high oil content in the samples we could not filter and preserve the biomass immediately, so we selected to flash freeze them.
What is the best way to thaw these samples so we can collect and preserve the biomass without allowing RNA to degrade?
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I'm having trouble with this too. My samples were frozen at -20C and if stored in large quantities, the long thawing process seems to ruin most of the RNA. For the smaller samples, it sometimes works but appears to depend on how long the samples were frozen for. What have you found?
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I would like to extract free DNA, not enclosed in bacterial cells, from an environmental water sample. First, I will filter my sample (10L) through a 0.2 um PES filter for getting rid of bacterial cells but then I do not know how to concentrate the filtrate to get a good quality DNA sample. Any suggestion?
Thank you.
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Hello Ryan William Orr , we published this year the way we developed for isolating free-floating extracellular DNA. Here the link:
BR,
David
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Upon collection of a freshwater sample, does it need to be immediately frozen for ammonia analysis at a later date or can it be left at ambient temperature for up to 24 hours before it is frozen? I'm aware that bacteria can alter water parameters over time but I don't know whether it would have a significant affect if the sample if frozen within 24 hours.
Any help would be appreciated - thank you in advance!
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Megan..... Ammonia forms hydrogen bonding with water molecules and this will increase the strength of the solution. However, freezing the sample will help the stability of the solution, The concentration level will be kept representative of the originally samples water.
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I want to screen the presence of plastic additives in a few water samples using HPLC-UV. I am very new to HPLC, and after doing a reading on the sample preparation for HPLC, I found there are a few methods and procedures that can be applied such as; solid-phase extraction, etc. However, I am not sure which method suits my water samples. Can anyone suggest me what the best sample extraction and preparation needed before testing it using HPLC?
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Dear Hanis,
Your question concerns several factors:
Plastic additives: what kind of additives? Depending on their nature and composition you can select the proper HPLC operational system (column, eluens and type of detector). Assuming that you mean UV absorbing constituents you might find valuable information about extraction and sampole preparation in these publications:
or
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I work on photocatalysis; its regarding the activity of photocatlayst? i want to know the best suitable technique for My degraded product proof ??
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You must discuss more details about the nature of pollutant in your water sample.
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Any help would be much appreciated and thanks in advance! I have a selection of 50ml frozen water samples that I need to conduct ammonia assays on and was wondering how long is "safe" enough to leave the defrosted samples without degrading the sample. Can I leave them overnight to defrost and analyse them the following morning or is this too long?
Thanks again!
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Ammonia is lighter than air and can be frozen77.7-degree at 77.7 degrees centigrade. Before performing an ammonia test of frozen water it is necessary to keep it at room temperature then perform the tests.
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I have read in many articles regarding use of specific SRM while analyzing trace elements in biological sample and want to know if its really important or can we just go for a common one.
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Nida Kanwal SRM is always needed to validate the results. SRM must be processed together with the analytical samples to ensure that all the laboratory procedures used during the process were correct. SRM serves as a quality check for the whole procedure, including sample preparation.
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These colonies are inoculated on TCBS Agar from water sample of ornamental fish tank. Most of them - green colonies are Vibrio sp.. I don't know which species the light-green serrated amorphous colonies are. I am going to identify them. Thank you so much everyone.
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These colonies are belong to a species of the fungus Penicillium sp.
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I'm currently working on heavy metal concentration among water samples within a Barite mine area. From the results of the analysis, the order of dominance of heavy metals are Mn > Pb > Cd > Zn > Fe > Ba. The dominant lithology of the area is shale and sandstone units. However, the shale unit plays host to the mineralization. Galena and sphalerite are the major minerals found to occur in association with Barite mineralization in the area. So I want to know why Mn appears to be of higher concentration among the water samples.
Your inputs would be highly appreciated. Thanks
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Manganese is very abundant and distributed in the earth's crust in association with ores of iron. The major ores of manganese are pyrolusite (MnO2), hausmannite (Mn3O4) and manganite (MnO(OH)). Manganese is an essential trace element found naturally in lakes, rivers, and drinking water supply. Mining operation elevates the concentrations of manganese and iron in the environment, especially in the surface water. Though not a priority pollutant, high manganese concentration in the environment may become a threat to humans and aquatic organisms.
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We intend to find out the effect of cassava effluent on a particular river that serves various purposes downstream.
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@ Williams F. Hansen, thanks for the insight.
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I am planning to study the bacterial community composition in the backwash samples of a few drinking water treatment plants. I am also planning to enrich bacteria for a subsequent experiment later. Can anyone tell me how much backwash samples will I need for enrichment as well as to analyze community composition?
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Use this 👇
You need for each bacterial type and each sample , 10 ml × 5 for each double concentration tube , 1 ml × 5 for each simple concentration tube and 50 ml for the bottle.
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I am working on a manuscript about pharmaceuticals that have been detected in rivers in south east England. The Q-TOF mass spectrometer results from the water samples has given each pharmaceutical a compound area. The EU Water Framework Directive Watch List requires the quantification for each substance to be monitored. Is there an equation I can use to find out the nanogram per litre for each pharmaceutical please?
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Rosamund, as others have noted, you can not work out the amounts from just area reports, esp MS data. A full HPLC calibration for each and every analyte of interest would need to be carried out with proper replicates using high purity standards.
  • Mass detectors are not "universal" detectors. Their output varies and will change each time they are used, depending on the exact HPLC method of analysis, the sample type(s), detector type(s), parameters set in the software and the training of the operator.
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as ground water is used for drinking called karez water. three different water samples like storage tank, bore hole and underground aquifer(kareez) water samples were collected for comparison as stability of drinking. what is this type sampling called?
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Random sampling
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I want to calculate the salinity of my water sample. for that I measure the conductivity in microS/cm I want to change this to TDS (mg/L) and salinity percentage. How do I do that?
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First you convert micro Siemens/cm into “deci Siemens per metre” (dS/m)
Conversion factor is micro Siemens/cm x 0.001 = dS/m
From that you can calculate TDS (total Dissolved Solids) that is in mg/L
TDS (mg/L) = EC (dS/m) x 640
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I would like to measure the concentration of antibiotics in water samples using UV instrument. However, the concentration of dissolved iron in the samples is high which make significant interference during UV analysis. How can we reduce the concentration of iron in order to eliminate the iron interference?
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The simplest solution is to treat with chelex-100 resin (sodium form; Sigma product C7901) and filter the resin using a 0.2 u filter. You probably need 5 to 10 mg of the chelex resin per mL of water sample.
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Plotting specific conductance versus total dissolved solids (TDS) from measured water quality data from water wells in the Hill Country region of Texas, United States, yields two distinct trends (Figure 1). This presents a problem when estimating TDS in this region, either from measuring specific conductance from water samples, or from calculating formation water resistivity from geophysical well logs. The two trends were visually isolated (Figures 2 and 3) for comparison of chemical, spatial, and formational patterns between the two. Analysis of the two trends reveals the water for each is identical in terms of major and common minor constituents (Figure 4), the two trends occur in all formations of the Trinity aquifer system, and there is no overall regional pattern of one trend vs the other, though the trends locally cluster (Figure 5, example from the Upper Glen Rose Formation). Water of both trends are dominated by Ca-Mg-HCO3 and Ca-Mg-SO4, and as TDS increases, calcium-magnesium-sulfate becomes the dominant water type, with up to 94% of the total milliequivalents per liter comprised of Ca-Mg-SO4.
Initial thoughts were the difference in the trends could be explained by ion complexing in some areas but not others, perhaps catalyzed by subtle geochemical constituents in the subsurface, or Eh-pH conditions (there is no significant difference in pH between the two trends). But current thoughts are that ion complexing cannot explain a nearly 50% reduction in specific conductivity from the lower trend to the upper trend (given the same TDS value), which would require nearly 50% of the ions to form complexes. Other hypothesis is the difference between the two trends could be due to bias in sampling and analysis. Perhaps for the upper trend nearly 50% of the Ca-Mg-SO4 precipitates as solid CaSO4 and MgSO4 when sampled and specific conductance is measured (measuring a low specific conductance relative to the weight of constituents in the water), whereas the sample is then mixed at the laboratory and the precipitate is re-dissolved before analyzing the concentration of constituents. This is only a conjecture. I am not a geochemist and I have rudimentary knowledge of water sampling procedures – my background is primarily geologic mapping and structural geology.
Points of discussion regarding this are:
· What are the potential explanations for two significantly different trends of TDS versus specific conductance for otherwise identical water types? Keep in mind the water types in this case are dominantly Ca-Mg-HCO3 and Ca-Mg-SO4 (the latter dominating at higher TDS)
· Could ion complexing be responsible, or is the magnitude of decreased specific conductance demonstrated above too great?
· Do you know of any other studies where two trends of TDS versus specific conductance has been examined for a region, or other relevant publications?
· Which of the two trends are more likely to occur in the subsurface? Or is it likely they both occur locally in the subsurface? (Our goal is to estimate TDS from resistivity logs; thus, we need a single, reliable TDS vs specific conductance trend)
· Are you familiar with collecting, sampling, and analyzing water samples, and have some insight into whether the specific conductance could measure relatively very low for a given quality or water?
A copy of the data is attached (there are two tabs, one for each trend). Thank you for considering this problem!
Evan Strickland, P.G. | Geoscientist
Texas Water Development Board
Innovative Water Technologies | BRACS team
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Credit is due to F. Paul Bertetti, P.G., who identified this lab as a source of erroneous conductance measurements in an unpublished report.
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How much Zn-acetate is required in say, 100 mL sample? How to prepare Zn acetate solution from powder? Is there a standard method for water sampling?
I was thinking I could...
A) Preload bottle with powdered Zn-acetate
B) Make solution with powder, pre-load bottle day of sampling with solution
But still not sure how much solution or powder to use per given volume, or concentration of solution.
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2mL (2% of the sample)
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Using cathodes to measure the ion concentrations as Cl-, F-, Br-, CN- by reading the M.voltage of water samples.
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Following