Fluoride - Science topic

To calculate the detection limit (LOD) and quantification limit (LOQ) in ion chromatography, use the formulas LOD = 3.3s/m and LOQ = 10s/m, where s is the standard deviation of the blank and m is the slope of the calibration curve. Construct a calibration curve with standards to ensure linearity and calculate s and m accurately.

Did you simply measure the absorbance of the fluoride without any treatment? If so, when you introduce the dilution factor (DF) in your calculation does not matter, you should still get comparable result.

However, if your sample has been treated before measurement, say you added an indicator or you heated. When you introduce you DF depends on when the dilution was done. If dilution was done after treatment, then absorbance must be multiplied by DF before calculation of concentration; if dilution was done before treatment, then the concentration should be calculated first and afterwards multiplied by the DF.

Post-treatment dilution has a higher tendency of shifting the intercept of your calibration curve, while the pre-treatment dilution, theoretically, should not interfer with the intercept.

Üretilen lif kullanılan malzemeye zarar vermiyorsa her zaman kullanılabilir. Lifin uygulanacağı yüzeyin zarar görüp görmeyeceği malzeme yüzeyinin sahip olduğu özelliklere bağlı olur.

LiF has poor solubility in water. Increase the number of washing cycles and try to use warm water to improve LiF solubility.

The presence of Al in EDS/SEM can indicate that the etching time was not sufficient. You can corroborate this with simple XRD analysis.

You do not specify the centrifugation parameters, but 3500-4500 rpm @ 5min should be sufficient to precipitate the impurities you have (Al, LiF, etc).

So:

Dear Chehat Nour El Houda ,

please see for example:

Best regards

G.M.

For the life time estimation of Corona virus on different metal surfaces and solvents, kindly read the recently published article: Theory for Nanoscale Curvature Induced Enhanced Inactivation Kinetics of SARS-CoV-2, Nanoscale 2022, 14, 5600-5611.

This is the error message

Thank you, I need anhydrous material .( i.e. I manufacture simple hydrate salts, so the chemistry is pretty easy) . I was looking for a cheap available ionic solvent(s)

Hello, Dear Geoff.

We continue to work on the subject you mentioned. There are methods that can analyze this.

Dear Moses Egor sorry to see that your interesting technical question has not yet received any expert answers. As a synthetic inorganic chemist I'm clearly not a specialist in this field enough to provide you with a qualified answer. All I can do right now is suggest to you a potentially useful article which might perhaps help you in you analysis (I'm not sure if it does 😳):

This paper is freely available as public full text (please see the attached pdf file).

Good luck with your work and best wishes!

Dear Nissem: P.S. For the second part of your question ("Or Fluorine release in aqueous solutions ?") please note that fluorine can only be released from any materials in the form of fluoride ions. You are absolutely right in that a specific fluoride ion electrode is useful to quantify the fluoride release. For a potentially useful protocol please have a look at the following article:

Fortunately this article has been posted by the authors as public full text on RG. Thus you can freely download it as pdf file and print it out if required.

Geoff Pain an interesting correlation and sophisticated question. Look, what I would like to present is a simplified iron (fe) perspective while trying to link with all of your proposals and observations. First, fluoride appears to cause iron overload:

Uric acid is suggested as a telltale signal of early iron overload

Finally, instead of a causative role, uric acid appears to be the way the body attempts to mitigate excess iron since it is a powerful heavy metal chelator

"Urate acts as a chelator for iron and, in turn, iron can modulate the activity of xanthine oxidase and the production of urate"

As we are aware covid-19 actively tries to increase the availability of serum iron levels to replicate faster

It would seem that high initial uric acid levels would signal the increase of iron or the fact that the patient has some form of iron overload in the first place. Then at the next stage, Covid19 would attack the areas that produce uric acid thus removing its chelating effects. Uric acid is synthesized mainly in the liver, intestines and vascular endothelium. So it is no surprise that

https://www.nature.com/articles/s41392-020-00373-7

All of these mean that Hypouricemia would be the end game.

https://www.frontiersin.org/articles/633767

"studies have shown that serum uric acid concentrations were markedly lower in patients with severe COVID-19 disease"

Now I need a little help with why attacking the kidneys would be advantageous

but nobody is perfect;-)

https://www.ajmc.com/view/lancet-covid-19-virus-can-attack-kidneys-speeding-death

Sincerely

Prof Christopher G YUKNA

PS Fernando Kemta Lekpa African Americans suffer from gout more often and have higher serum iron levels than the rest of the American population which in the context of this discussion may have been due to adapting to deal with the malaria parasite. Just an idea but the research supports the hypothesis.

Dear Bandi Hari addition of urea and ammonium fluoride has nothing to do with avoiding oxidation of ions. Especially vanadium with remain pentavalent throughout the reaction. As you can see from the attached reference, urea and ammonium fluoride as added as some kind of "surfactants" in order to influence the morphology of the resulting crystals (i.e. plate-like, rod-like etc.):

(see attachment)

I hope this answers your original question. Good luck and best wishes, Frank Edelmann

Fluorapatite is not influenced by just one factor that is dentifrices, Its formation is a much dynamic process influenced by various factors ranging from

1. Systemic administration of fluoride at the time of enamel formation and early tooth eruption,

2. Daily dietary intake of fluoride,

3. Intake of fluoride from additional resources like Tea, fish vegetables, food cooked in Teflon coated utensils etc.

3. Loss of hydroxyapatite to gain of fluorapatite ratio,

4. Availability of free fluoride ions

5. Bare minimum concentration of 500 ppm for children and 800-1000 ppm and above the optimum level of fluoride for adult usage in dentifrices.

Dear Vladimir Paygin thank you for asking this interesting technical question. Please have a look at the following link:

This supplier promises worldwide shipping.

Please also see the following original research article in which the preparatiom of lithium fluoride nanoparticles is described:

The article is freely available as public full text on RG.

Good luck with your research! 👍

You must avoid using expired things.

You can use common blood tubes with anticiagulant (heparin and EDTA) for this. But to aboid glucose and lactate changes, you must immediately centrifuge the samples at 4 C and separate plasma and freeze or analyze it.

Dear Sumit Bhowmick ,

You can decompose H2SiF6 by heating into HF and SiF4 you can separate them by fractional distillation.

Then you can extract silicon by reducing SiF4 at high temperature into suitable reactors as:

SiF4 +2H2 = Si + 4 HF

Best wishes

Dear Flavio Salomao-Miranda thanks for the interesting question. Please see the following useful articles which are both freely available as public full texts on RG:

1. Salivary fluoride concentration after the use of a fluoridated dentifrice, preceded

2. Measuring fluoride in human saliva and water

Following

You can use alumina crucible!

hi

is it possible that only some ppm level fluoride sorbent is activated by given methods you need to atjust the consentration of some suitable alums qty

The two materials, ZOE and topical Fluoride, are different with regard to their reactivity to dentin. Fluoride is incapable of sealing the exposed dentinal tubules. ZOE, on the other hand, plugs the open tubules with the formation of an insoluble CaZ-eugenolate complex.

Have you tried VulcanChem or Zinc15?

That's a good question

Dear Darwin H. Pangaribuan, another important aspect here is whether or not you exceeded the official threshold values for sulfuryl fluoride.

I understand that Roger Seheult, California, has been trying to understand the pathophysiology of Covid -19 based on his reading of the literature, including papers sent to him by others. There are a number of papers that address the value of NAC in treating respiratory illness and the effects of oxidative stress on von Willebrand factor. Roger came up with the idea of treating Covid19 with NAC but in MedCram 70 he notes that Alexey Polonikov, Kursk State Medical University has also reported a series of patients with Covid-19 and sees endogenous deficiency of glutathione as the most likely cause of serious manifestations and death. Polonikov sees oxidative stress as contributing to the hyperinflammation of the lung and poor antioxidant defences as being due to glutathione deficiency. He recommends treatment with N-acetylcysteine and reduced glutathione. Seheult notes that it appears that the impaired lung oxygenation is related in part to thromobosis of pulmonary arterioles because of the von Willibrand factor molecules from platelets adhering to one another. The clots consist of long strands bound to one another by disulphide bonds. The NAC or reduced glutathione break the linked chains apart by breaking up the SS bonds through reducing them by changing them to SH SH so that the chains are no longer linked together. When the clots are lysed with NAC the hypoxaemia may be relieved. Seheult notes that there are different VWF levels in Group O patients and some racial groups (higher in Americans of African heritage). SARSCoV2 can cause a550% increases in VWF levels and the NAC can reduce this. Polonikov measured the Reactive Oxygen Species/Glutathione ratio. Patients with ratios of 2.9 and 1.2 did better (recovered without treatment) than those with rations of 34.6 (unwell 13 days) and 6.9 (still unwell after 11 days). Clinical trials of NAC for prevention and treatment awaited.

Very interesting question, I’m interested because dentists use/prescribe fluoride all the time.

Dear Efrain Ochoa, I think if you work quickly, you should be able to briefly handle your lithium fluoride sputtering targets in dry air. In the attached article it is atated that "LiF is an almost non-hygroscopic alkali halide with good stability and simple structure (few electrons). This should facilitate experimental and theoretical analysis." (marked in yellow).

Any relevant studies (RCT) reporting the same ?

You included little in the way of details. ISE is labor intensive and has problems with interferences. IC is easy enough to do but the sample should be clean. It is also very expensive to set up. HPLC is a non starter.

Dear Aayush Rai

the issue with reducing the ionic strength of the eluent, as suggested in previous messages, is that stronger retained matrix anions will stick on the column. It is for this reason, that you should keep the need for either a column rinsing step with a higher ionic strength solution in mind (could be as simple as a step gradient) or that you consider a continuous linear gradient - usually using hydroxide based eluents. If you do not rinse the column regularly an increasing amount of ions will be concentrated on the column, and the retention times will shrink, and you will lose resolution.

Using a continuous hydroxide gradient, you'd be able to elute and analyze other inorganic and organic anions in the "salty" matrix as well. Having said "salty": Because of the high salt concentration of the urine sample, you should consider a high capacity ion-exchange column to prevent overloading. Modern ion exchangers provide high (loading) capacity and high chromatographic efficiency. This allows the analyst to separate close eluting peaks in high ionic strength matrices. Because of the high ion exchange capacity, the use of high ionic strength eluents is the consequence so that you please check the "suppression" capacity of the anion suppressor you use. In the case of continuously regenerated membrane-based suppressors, you have a high dynamic suppression capacity and in most cases, you are well equipped. In the case of discontinuously operated packed bed suppressors, you need to check the static capacity and see how long you can operate the pack bed suppressor column before you need to switch (hence, discontinuously operated).

I checked what is available on the Web, and found the following URL (see below). This is an older example of what was possible several years ago. Today, with the higher capacity column (see above) the separations will be much better and the peaks more efficient.

As I don't know the equipment you use, I would suggest checking the paper and getting in touch with your nearest customer support organization to see what is possible.

I hope this is of some help.

All the very best for your research,

Detlef.

https://assets.thermofisher.com/TFS-Assets/CMD/Application-Notes/4664-AN107_LPN0675.pdf

Thanks a lot Alessandro.

Quite an interesting query..Will follow up the discussion for my better understanding..

Thanks for the Sharing..

It is possible that sulfur hexafluoride, SF₆, is present in volcanic emissions (see reference below). Among all sulfur fluorides, SF₆ ist by far the most stable. The compound is rather inert and also a very potent greenhouse gas.

Dear Hani,

this is an interesting question. Of the many benefits of tea, idid not know that this was one of them. I do not know if fluoridated water is necessary, but it would be an enhancement. I am sending 2 links. Green and oolong teas fight cavities.

brigid

Fluoride can be determined by potentiometric (ISE), colorimetric (SPADNS) and Gas chromatographic(GC) methods. However colorimetric method is time consuming and not used in biological media such as blood and urine. ISE method is most frequently used method for fluoride measurement in biological media. It utilizes a membrane consisting of a slice of single crystal of lanthanum fluoride doped with europium(II). SPADNS method is used in UV Spectrophotometer.

I was interested to learn that Hydrogen Fluoride gas was measured using FTIR spectrometry from a boat as well as on the crater at Whakaari White Island, New Zealand. Reference: Love SP et al. 2000. Passive Infrared Spectroscopic Remote Sensing of Volcanic Gases: Ground-Based Studies at White Island and Ruapehu, New Zealand, and Popocatepetl, Mexico. in Remote Sensing of Active Volcanism. Volume 16. Wiley

Chandrika Priyadarshani

Adsorption is a spontaneous process. Otherwise, without your help, fluorine molecules will be adsorbed on metal oxide nanoparticles. You need to determine the equilibrium constant of adsorption at two temperatures, and from these data you can determine the change in enthalpy during adsorption. With the help of the equilibrium constant, you can determine the change in Gibbs energy in the process of adsorption. There are a lot of mistakes in your question. You have to clarify your question.

Below articles might be helpful.

Regards,

Indrani

The draft report is horrendous. The information on the thyroid issue is so wrong, it is mind-boggling. Not surprised though.

Dear Geof,

I had a look at material safety data sheet of Glyphosate and it states that this compound is sensitive to fluorine due to high oxidation potential of F2.

This seems reasonable as C-P bond in Glyphosate looks like something that can get oxidised quite easily. I have found a couple of articles supporting this hypothesis:

Can easily be determined with thermodynamic calculations.

2CuI + H2(g) = 2Cu + 2HI(g)

deltaG - temp.

kcal - ^oC

36.896 - 0

33.206 - 100

29.696 - 200

26.361 - 300

23.372 - 400

21.107 - 500

2CuF + H2(g) = 2Cu + 2HF(g)

deltaG - temp.

kcal - ^oC

-16.351 - 0

-19.961 - 100

-23.382 - 200

-26.635 - 300

-29.741 - 400

-32.716 - 500

Dear Dr. Nwanosike

Bone char is a good option, there are several studies of groundwater fluorine removal using this material:

Best Regards.

I should add, the ICS5000 instrument also has an anion suppressor which will greatly influence the analysis. Some for purchasing the columns please be aware that may not speed up the analysis in your system.

regards,

B

Thanks Goyal Ji

Tea tasting is the process in which a trained taster determines the quality of a particular tea. Due to climatic conditions, topography, manufacturing process, and different clones of the Camellia sinensis plant (tea), the final product may have vastly differing flavours and appearance

to use neutron scattering method

There is a paper that goes into detail about the methods to determine fluoride in toothpastes:

To convert fluoride compound into fluoride ion for sodium fluoride (NaF) divide by 2.21. For sodium silicofluoride (Na2SIF6) divide by 1.65. For fluorosilicic acid (H2SiF6) divide by 1.26. Thus, 1 mg of NaF contain 0.45 mg F ion, Na2SIF6 contain 0.61 mg F ion, and H2SiF6 contain 0.79 mg F ion. Collectively, the sum of F ions in one mg of these compounds is 1.85 mg. If all these compounds are used to fluoridate water at one mg F ion per liter, then the 1.85 mg should added to 1,850 ml of water OR 0.1 mg per 100 ml. If individually then turn to the conversion ratio as above. Good luck.

For the measurent of iodine in urine and serum please refer J Rendi 1998.

for Fluoride refer K ItaI 2001

detailed information on line available

Effectively the potentiometric method is the most appropriate you have to opt for a combined F electrode

Dear Alan,

We published a paper in Journal of "Desalination and Water Treatment" in 2014. I have attached the paper to the answer. In Figure 7 a, b, c, d there are 1 to 3 peaks. What do you think of the results? I measured particle size and size distribution of pure water and get 1 or two peaks. The results are repeatable. Please measure at least 6 times of each sample then give your invaluable explanation and insightful conclusion.

Thank you very much in advance.

Kind regards,

Li Shu

It could be that the solution is too dilute to overwhelm the buffering capacity of the indicator itself.

Dear Michael after reading your answer i did look up to the internet and started reaading bout flouride in water.

I am now able to get some insight about the big problem the humans are facing.

Lets hope that the council for water management will take up the issue in a more seroius manner.

It also has made a difference to my understnading of the disease patterns of autoimmunity.

Thank you for the insights.

Dear Geoff,

That is an interesting hypothesis regarding the low |F-| concentrations measured with an ion-selective electrode. I don't know if there are any experimental measurements, but from my point of view, as a theoretical chemist, I'd say an assessment of the stability of FHF in aqueous solution is paramount as a first step to understand speciation of F- in biological media. Quite often, stable structures formed either in gas-phase or in solids are highly unstable in aqueous solution. Furthermore, I believe experimental data regarding the stability of FHF in aqueous solution is much easier to come by in the literature than in biological samples.

I hope this helps.

All the best.

The Si-F bond is quite strong, so you might have to drive precipitation of insoluble polysilicates before attempting to measure the F- liberated.

Ion selective electrode method is best for Fluoride analysis. Thirmo Orion ion meters are very good for Fluoride.

SPADNS method (APHA) is also good if the F conc is low (0-1.4mg/L). Refere APHA for detailed protocol.

I agree, none of the articles talks about fluorosis, but the original question is: why if it has been shown that fluoride is toxic, it has not been banned, my answer is yes, Fluoride is toxic, but for produce the effects that are mentioned in the articles on which Dr. Pain is based, the doses are much higher than those used to prevent the caries process.

In some parts of my country, drinking water contains cyanide, but the doses are lower than those that produce toxic effects.

I have started using SDF recently. I use GIC to mask the Black colour in Primary teeth. The far reaching benefits of SDF do not compel us to excavate discoloured dentin. A sandwich restoration of GIC+ Light cured composite helps for sure.

It could be a better hypothesis. By the way, I am not a specialist either. I just came across the following chapter, which should be useful:

Engineering » Electrical and Electronic Engineering » "Dielectric Material", book edited by Marius Alexandru Silaghi, ISBN 978-953-51-0764-4, Published: October 3, 2012 under CC BY 3.0 license. © The Author(s).

By Zulkifli Ahmad DOI: 10.5772/50638

The major environmental impacts associated to groundwater over-drafting are decline of water level, water scarcity, damage to connected wetlands, and sometimes salt-water intrusion.

So. there should be some national policy on the groundwater extraction - a regulatory authority need to be established to ensure the sustainable use of this natural resource. Tax based on the quantity of withdrawal can be imposed to minimize the wastage of water.

Regards

Dear Sunil,

The removal of fluoride from an aquifer itself is not possible. But, its concentration can be reduced through dilution by injecting water into the aquifer (artificial recharge). Some have already mentioned this.

Various researchers have applied this method and was found to be effective in insitu dilution of fluoride content.

However, several investigations have been carried out on defluoridation of groundwater (pumping out groundwater) - Prof. Achour has given some indications.

I have provided a brief review on defluoridation of groundwater on reply of a question. You may read the same (link given below).

In this context, I like to mention that we have developed a method for defluoridation of water and filed for patent (The technology already transferred).

Best wishes

Due to the different natures of both materials (glass ionomer and composites) a few rules should be observed: glass ionomer adheres better to the root surface, while composites adhere better to enamel. Therefore it is crucial not to remove any healthy enamel at the CEJ and preserve even small amounts that would help to bond the composite to. To combine the advantages of both materials, the sandwich technique is being used. https://www.slideshare.net/mobile/ruhi_kashmiri/sandwich-technique-61386414

TBA fluoride is thermally unstable.  It decomoses into butene and tributylamine.  This process is spontaneous in either the gas phase or in liquid solution starting around 30-35C.  If I remember correctly, this reaction is called a Hoffman elimination.  The fluoride is less stable than the hydroxide or other salts of TBA.

immunocytology investigation

labricarion may be?

Often, hydrofluoric acid ― when used as etchant ― can be substituted by Buffered Hydrofluoric Acid (BHF) or Buffered Oxide Etch (BOE) (*), which often contains NH₄F and HF aq.; by NH₄HF₂ (or KHF₂) + HCl conc. aq.; or by hexafluorosilicic acid (fluosilic acid). 

(*) https://en.wikipedia.org/wiki/Buffered_oxide_etch

You need to synthesize selective binders such as calixpyrroles or other pyrrole derivatives for fluoride ion binding and load them on to solid nanomaterials for example magnetic nanoparticles etc. If you search on google you may get many such articles. 

after fluoride adsorption with red mud, the leaching tests with the residue showed appreciable leaching of the fluoride back into the water. 

Is there any method to stop the leaching of fluoride back into the water, by adding some chemical or so?.

I think it has to be something like glass etching by HF! it is like making some scratches on a surface and making a coarse surface.

hi see this attach can help  you 

Deep groundwater and/or geothermal waters is generally high in Flouride cocentration. In the a river stream that is recharged by groundwater it is neccesary to check such possibilities...

Good luck!

i think no as there will be no free HF

Dear Saravanan,

Here is an interesting document concerning health risks from drinking demineralised water. You will also find the quality standards required. This document is from WHO.

With my best regards

Prof. Bachir ACHOUR

David:

You may like to have a look at this helpful link:

Best

Syed