Questions related to Environmental Analytical Chemistry
I was interested in conferences in the field of environmental analytical chemistry, which will take place in 2022. I have found a number of conferences called "International Conference on Chemical and Environmental Science (ICCES)", which will be organized. An example is this conference in Estonia:
I assume that this is a suspicious conference. The table with deadlines also looks strange. In terms of the volume of conferences, it resembles WASET, which is discussed here and on other sites. However, does anyone have a personal experience with the organizer - iser.co?
Dear to whom it may concern,
I have been developing a solid phase extraction-based sample preparation method for environmental samples.
I would sincerely like to ask you about the SPE process namely that after loading the samples onto SPE cartridges, I am wondering which next steps will be carried out:
1. Rinse these cartridges with the weakest elution strength solvent (for example, water or water with 5% MeOH for C-18 SPE adsorbent), Or
2. Dry these cartridges under nitrogen stream for 15 or 30 mins, Or
3. Do both of the steps in order: rinse these cartridges and then, dry them.
In case of drying these cartridges, how long should the step be carried out? As far as I know, some compounds can be more strongly trapped onto these cartridges, leading to their low recovery if the step last for a longer time.
I hope that you may spend a little time helping me clear the inquiry.
Thank you so much.
Dear to whom it may concern,
Based on ChemAxon, I calculated pKa values of Acesulfame as follows:
1. pKa (Strongest Acidic): 3.02
2. pKa (Strongest Basic): -6
Because I would like to convert Acesulfame Potassium into Acesulfame, I intend to use a stronger acid such as HCOOH or HCl than Acesulfame to do this conversion.
I am wondering whether this approach will really work or not.
May you please share your opinion with me?
Thanks in advance,
Quynh Khoa Pham.
Dear to whom it may concern,
I am investigating carbonaceous materials to treat aqueous samples but I have no knowledge of these materials.
May I ask you some questions as follows?
1. Whether these materials possess both polar and non-polar interactions
2. May you please show me mechanisms by which we can explain why these materials have the above properties?
Thank you so much.
Hello and thanks in advance!
I'm trying to separate an amino acid standard, but have been only seeing 2 peaks, one internal standard (ABA) and one broad peak around 17 minutes.
I've been using the same conditions as Liu, J. Chromatog. A, 1994, 670, 59-66, basically, using 6- AQC to derivitise,
wavelength at 248 nm,
Waters Eluent A as eluent A and acetonitrile and water as eluent B,
run time of 46 minutes,
flow rate of 1 ml/min,
C18 AccQ.Tag column.
I'm stumped as to why this is happening. Thanks for any help!
This is the third call for applications for Short Term Scientific Missions (STSMs) for grant period 2 of the COST Action CA17136 - INDAIRPOLLNET (https://indairpollnet.eu/). STSMs are institutional visits aimed at supporting individual mobility, fostering collaboration between individuals. These missions contribute to the scientific objectives of COST Action CA17136 - INDAIRPOLLNET. They are particularly intended for young scientists. The selection of applicants is based on the scientific scope of the STSM application which must clearly contribute to the overall objectives of the Action CA17136 and be related to a specific Working Group. Interested researchers can apply by following the instructions provided in the attached document and submitting their application and supporting documents until 31 January 2020.
Which one is more suitable to measure heavy metal uptake by aquatic plants.
Can anybody provide me these 2 equations with references?
I have a solution of both Peroxydisulfate (S2O82-) and Hydrogen Peroxide, and most methods used to detect Peroxydisulfate (S2O82-) interfere with H2O2 because of the similar O-O bond. How can we quantify one without the interference of the other?
Determination of trace concentrations of phenol in aqueous solutions.
I'm looking for a relatively simple analytical method (colorimetric analysis etc.) for measuring methanol in aqueous solutions in the concentration of about 100 µM ?
Hi all, I was looking to confirm whether it is necessary to acidify a solution sample prior to AAS (to measure the concentration of a metal in solution).
I ask this as I am working with bacteria which may or may not have the capacity to precipitate cadmium. I was hoping to detect cadmium precipitation in a culture supernatant by comparing the Cd concentration of a strong acid-digested supernatant sample (revealing total Cd in sample) to a non-acid digested sample (revealing only soluble Cd).
Ideally if bioprecipitation is present, the acid-digested sample would would have a much higher Cd concentration than the non-digested sample. The difference in Cd between the two readings would represent the Cd that has been precipitated into an insoluble compound (eg. cadmium carbonate, cadmium sulfide, etc).
However if samples need to be acidified prior to AAS in the first place, the above logic will not hold true.
I really appreciate any help with the above question, if I am not explaining the problem effectively please let me know.
I am using the standard in the form of mixture i.e EPA VOC Mix 2 (2000 microgram per ml each component in methanol). As mentioned in COA, it is having 14 components / analytes. When this particular mixture was run on HPLC, it did not give all 14 peaks of different components. It gave only one broader peak with some minute peaks. The mobile phase utilized was Acetonitrile : Deionized Water. Why separate peaks were not being identified? What should be done / Which parameter of HPLC should be altered so that separate peaks could be identified?
Three specific aldehydes seem to appear in all analyses of VOCs in ambient air or from material emissions. Can the occurrence of nonanal, decanal, and benzaldehyde be explained by degradation of the adsorbent polymer? These are always observed by some, ignored by others. There is no consensus on their origin or relevance. Can anybody shed more light?
Calcium carbonate can form both through chemical precipitation in water column and dissolution of organic shells. So how can you differentiate between these two sources from total carbon and total inorganic carbon data?
I am a PhD student at UPC (Spain) and I need some thermodynamic data, and my directors asked me about MEPHISTA and getting the information in order to understand some fission products behaviour but I don't know how to get them.
I am about to start a method for the analysis of aromatic amines in waste water samples after a derivatisation step. So, I was wondering, which will be the best column to give a low detection limit of between 0.01 to 1ug/l.
I am considering vapour-liquid and liquid-liquid equilibrium between water and hydrocarbon phase. I am getting correct water dew point for aqueous phase containing salt by equating fugacity of components in vapour phase with fugacity/ activity of components in liquid phase after due reduction in liquid mole fraction because of addition of salt. However when I am calculating liquid-liquid equilibrium between aqueous phase and liquid hydrocarbon phase, reduction in liquid mole fraction because of addition of salt leads to wrong values. Does salt concentration effect in water for liquid-liquid equilibrium only limited to the change in activity coefficient of water because of addition of salt and should we not consider the reduction in liquid mole fraction pf aqueous phase because of addition of salt while calculating liquid-liquid equilibrium?
I gone through some books regard to green house gases... in some books they are pointed that, SO2 is indirectly contribute green house effect... and in some books they are not pointed SO2 regard to Green house gases.. So.. I am in confusing ... so I need clarify.. so please....
i do not get a clear understanding on the procedure i should follow in order to analyse heavy metals in an anaerobic digestion sludge, using AAS
I was measuring radon with AlphaE (product of Saphymo)
On the screen, the "NOISE" response appeared.
I tried to start another measurement but the "NOISE" was still on it during several days...
I could not find sufficient info in the instrument manual...
Many thanks for your help
I want to measure the key nutrient levels such as nitrate, nitrite, phosphate, ammonia and silicate in the coral reef waters directly on the field. Please suggest me a reliable device suiting my purpose.
I am currently trying to narrow down which set of salts (AOAC, EN, Original) should be used to extract imidacloprid residues from dairy cattle manure using QuEChERS method, as well the sorbents to be used for cleanup using d-SPE. Our initial extractions using just acetonitrile and water (80/20) yielded a dark, yellowish-brown liquid. Samples are to be run on HPLC after extraction. Any comments would be appreciated!
Can anybody let me clear or describe the way to get answer of above mentioned questions? I had matched the result of our samples from online search NIST/EPA Library and identified our compounds.
Metals in soil are partitioned between the solid and solution phases of soils. In which of these forms are earthworms exposed to the metal concentrations in soil??
I have an aeration tank and feed it with wastewater. MLSS tests show that the growth is slowly, only 400 or 500 mg/l per day. my tank MLSS is 5000 mg/l and my target is 12000 mg/l.
It is believed that the hydrogen peroxide was higher in the early earth due to the anaerobic conditions, and what is the role for its decomposition for life evolution? I have noticed that many inorganic nano materials were found to have the " peroxidase-like activity" and these materials might be presented in the early ocean. For example, different type of iron oxide ( e.g. Fe3O4, Fe2O3, FeOOH), CoFe2O4, MnFeO4, MFe2O4 (M=Mg, Ni, Cu), MnO2, FeWO4 ,FeSe, α-MnSe, FeS, Fe3S4, CuS , CdS, MoS2, and WS2). Is any relation of the oxygen generation and these activity ?
If one is just given the Henry's Law constant (Kh) and octanol-water partitioning coefficient of a few organic molecules, how can you predict what instrument (between GC and HPLC) would be better suited to analyze each one?
I have been doing GC-MS analysis via SPME for spice volatiles for undergraduate research, using a modern Agilent GC-MS with SPME autosampler. Each injection was preceded by a 2-octanol standard, but over 30 replicates of the standard, peak area varies from approximately 2,000,000 to 76,000,000 area units! It isn't due to fibre degradation; I actually got the worst standard deviation 2 days after a new fibre had been fitted (SD 80% of the mean over 7 injections). Any ideas as to why? Most papers I have found talk about how reliable GC-MS is rather than reasons it may not be. Any papers you can point me to would be great, or some suggestions as to why! Thanks in advance.
I need a chemical that I can use to investigate the presence of Fe(IV) in my reaction process. I am wondering if there is a way to detect or refer to the presence of Fe(IV). Thanks
i have be trying to find the COD by using Dichromate and i found that the values of COD are coming in multiples of 4 i.e., 16,32,48,64,96.....which i find very absurd?What may be the possible cause for such results and i also wanted to know if there is any alternative to this?
need to compare the results of the metals present in the sediment samples collected from lagoon of Sri lanka.
I was not able to find out the complete list of pollution tolerant algae. Please help me in finding out the list.
Thanks in Advance
In Karnataka State ( HK Region) toor dal is major crops and peoples are consuming more for their daily food process. and This area of soil and ground water is contaminated with fluoride also. In this connection I wish to asses the fluoride contamination in toor daal.
I am doing analysis of PM10 collected on Quartz fiber filter.I am expecting organic compounds like n-alkanoic acids decanoic acid, dodecanoic acid etc...I have only one standard that is Heptadecanoic acid.Could i use this chemical for quantify all the acids by making calibration curve from this standard.
I am working on simple aromatic hydrocarbon molecules found in aquatic animals. I am very new to NMR. I have NMR spectra of several compound but i dont know how to determine their structure. Can you please give me any online/offline tool/software where i need to put the sprectra and the calculate the structure for me.
Thank you in advance
I need a refernce to an accurate method for the gravimetiric determination of the concentration of suspended particulate matter in deep ocean waters.
The method should be widely and currently used in deep sea research
we are analysing various ganoderic acids in Ganoderma Mushroom. What is the best labelled standard that i can use to calculate the recovery and EE of my method.
going to follow batch extraction test using EDTA to specify the best condition of pH,conc of extractant,agitation speed,contact time for identifying the effective removal of heavy metals from my sample..supernatant is further analysed by ICP.To anlaysing into ICP,is it necessary to change the supernatant into acid nature?(acid digestion method) or colourless(supernatant)....
We have prepared plastic with As+3 compound. We applied 250 C temperature and pressure during the processing samples. After preparation of sample As state has been changed to +5. Please let me how it was changed. We have mixed other inorganic compounds also such Fe, Pb, Cr etc.
I am working on microbial dye degradation. I have the data for absorption maxima for a particular dye.During my studies I found some of the dyes undergo first fungal biosorption then undergoes degradation or decolorization. The degradation may be complete or incomplete.How to check the decolorization efficiency ? Because culture filtrate contains no dye.
The needle of the SPME is bent during extraction (agitation) and it breaks. It happens every 6 or 7 samples. Can anybody give me an advice?
I had reviewed several times the alignment of holder, needle, etc.
For more information I am using the MassHunter for controlling the CTC sampler. My method requieres direct immersion and agitation.
Thank you very much
Even if I understand that some heavy metals such as Cd are more mobile than Pb, as an instance, I am still not sure why the Casparian Strip does not work avoiding the uptake of Cd, and whereas, this heavy metal can be translocated to the fruits and grains of plants. I mean, if the Casparian Strip really works, it means avoidance of entrance of all heavy metals, or is there any relationship with the valency of the chemistry of the particular metal? Thanks in advance
It is a known fact that there is not one "plant availability". Availability of metals and metaloids depends on many parameters of the soils (pH, EC, CEC etc.) as well as on plant physiology (rhizosphere processses). Until today a lot of methods have been developed (column elution methods, single step extraction, sequential extraction), however if one is interested in the availability of non essential trace elements for plant growth (e.g. lanthanides, uranium) what method is the best? Does anybody have experience in that?
Especially for simultaneous determination of different antibiotic classes and the most suitable analytical instrument.
I found this interesting paper that reports the relative water content (RWC) in the leaves of 13 woody species (between 77 and 91% of water).
But what about the rest of the tree. Of course I am not expecting an absolute answer as this would vary with species, age, season, health etc. But is there any study that has measured water content in whole trees?
Our large old distilled water still uses building steam from a 10 megawatt power plant. The still designer says the condensed water from the steam, which is used as feedwater, can't have more than 2 ppm of aliphatic hydrocarbons. Anti-corrosion and foaming additives for the boiler feedwater are the contributions to this. What's the best way to measure the steam condensate for this? It is cooled through a heat exchanger and used for the feedwater.
## Can anybody give me geochemical background concentration values of the elements in the Earth’s crust (crustal average).
### Also, I need a values of elements trace in :
"Clarke values" n chemical composition of the upper continental crust ( UCC) ( Taylor and McLennan, 1995).
Geochemical background concentration of the heavy metal (crustal average) (Taylor and McLennan, 1985)
I need for these Some papers :
 K. K. Turekian and K. H. Wedepohl, “Distribution of the elements in some major units of the earth’s crust,” Geological Society of America Bulletin, vol. 72, no. 2, pp. 175–192, 1961.
 D. R. Lide, CRC Handbook of Chemistry and Physics,Geophysics,Astronomy, and Acoustics, Abundance of Elements in the Earth’s Crust and in the Sea, section 14, CRC Press, Boca Raton, Fla,USA, 2005.
I´m working with insect d13C and d15N isotopes and we all know that insects are composed of a good percentage of chitin. I would be interested in knowing only carbon and nitrogen isotopes excluding the chitin contribution (since I processed the whole insect for another purpose). Does anybody know a correction factor available for chitin in insects? Or correction factors for similar material (cellulose, keratin???).
for wastewater analysis If I want to determine sulfate, sulfide, thiosulfate, and sulfite in one solution, can I use IC, or I have to use ICP? And any other method?
The typical WWTP effluent release standards for bacterial indicators do not include any information on levels of antibiotic resistant microbial levels or the potential for transfer, via genes, to environmental reservoirs. Additionally, the level of impacted bacteria in the viable but non-culturable state will confound these lab results and thus throw false negatives. As a consequence, what is actually being discharged remains an unknown and hence potentially severe long-term adverse public health risk
Dr Edo McGowan, former USAID Regional Environmental Officer covering Eastern and Southern Africa.
I did a sedimentary rock sample digestion of only 2g(required mass to test for presence of component) as prescribed by USEPA 3050B method on hot plate and tested for heavy metal presence after making up to 100ml. I now want to digest as large as 2kg(2000g) of the rock which will give about 100Litres of solution(by making up 100ml in 2g) for use as influent in column adsorption experiment to adsorb out the heavy metal. Can someone assist with minimum rock mass (e.g. 4g, 10g, 50g, etc.) to digest that still maintains good digestion process to achieve the 2kg sample?
I am trying to identify which rock type can be attributed in some results from XRF analysis concerning major and trace elements data. I trying to find one but it is quite difficult. I thought an online comparison should exist out there in the internet space.... And I need also the confidence level or all possibilities. Could you help? Thanks in advance!
In my research study, i am focusing into the treatment of organic compounds in rainwater using photocatalysis. the organic compounds involved in my study are Naphthalene, Fluoranthene, Pyrene, Lindane & DDT. In order to dissolve their powdered standard for preparing synthetic rainwater, I have been using an organic solvent, which is chloroform. Is there any further reactions that I should take note (since every compound will be degraded eventually) ? Which organic solvent (Eg: methyl chloride, methanol, choloroform, ethyl acetate, ethanol, etc.) that is suitable the most in dissolving the organic compounds i mentioned earlier?
I use the Rancimat to determine the shelf life of some edible oils, I need to know:
The minimum and the maximum limits of low-molecular weight of volatile organic compounds? and How the device converts the conductivity of water to the indicators of oxidative damage?
When it come to batch dissolution experiment (for water-rock interaction study), most authors have selected igneous rocks, sedimentary rocks and minerals formed under igneous conditions. Is there any special reason for that? Is there any article for the same experiment where metamorphic rocks were used?
The Hach Lange kit goes from 0-1000mg/L.
Hach Lange say their LOD is around 6ppm and the LOQ is 21ppm.
Does anyone know how they will determine the LOD and LOQ for these kits?
I understand that one would determine 3xstd(blank) to get the LOD, however because these are test vials, you need to blank initially with the blank you made. Would I then just read the blank after blanking with it?
A problem with these vials is that if I do blank with the blank and read it back it gives me zero as it should. But when you move the test vial slightly in the spec, the values no longer reads zero. this is because the glass vial is not optically the same at all points (and it is round which cause light scattering). I cant just keep moving the vial around and taking any reading I want.
Thank you very much.
what are the procedure(s) or techniques used for analyzing the components of wastewater especially antibiotics and organic compounds?