The microorganism keep shifting substrate in sulphide form to either elemental sulphur and other biproducts or to substrate in sulphate form.
Can you give a bit more details on the type of samples you are trying to assess and what you want to achieve exactly ?. Are you trying to assess sulfide and sulfates in solution or in other samples (solids, pore water, both) ?
Dear Olivier Braissant ,
I will be working on leaching of heavy metals from a waste sample by sulphur oxidizing bacteria (SOB). These bacteria acts on metal sulphides (eg: CuFeS2, present in waste sample - solid) and convert them to metal sulphate (soluble), which will come to solution. So, this solution is analysed for sulphate concentration and the waste sample (solid) is analysed for sulphide concentration. Overall motto is to understand the sulphur cycle of SOB.
You could be interested by the following article in which we developed a method to analyze sulphate and sulfide in samples from anaerobic digesters :
Percheron G, Bernet N & Moletta R (1996) A new method for the determination of dissolved sulfide in strongly colored anaerobically treated effluents. Bioprocess Engineering 15: 317-322.
Dear Mouna
Ion chromatography is usually rather inexpensive (if you have already the instrumentation) to assess the concentration of major ions and cations. With ion chromatography you might have to use some additional preparation steps (some specific syringe filters to remove humic acids and other materials that might interfere). Still the method can really helpful.
Alternatively if you plan to work on sediment sulfide microelectrode could be of interest however they will only measure free sulfide (not complex or precipitates).
There are also a long list of spectrophotometric assays that can be quite cheap. However it is much more time consuming usually. I will try to dig out an older reference listing the procedure for many of these assays. Unfortunately for now I am not in office.
Hey thanks Nicolas Bernet .. will go through the document and get back to you soon.
Dear Olivier, Thanks for that. That's all ok. If at all you find any spectrophotometric assay, kindly text me here or mail me at [email protected]
Mouna, you are asking to suggest a method to identify the amount: are you asking to estimate the amount of sulphur ?
Identify the amount, is not clear. Pl redefine your question.
By BITS pilani, I am reminded of my work at Khetri Copper complex .I mean working on Chalcopyrites,the sulphide ore of copper found there.
Ashok K Kaushal:
Hello Sir,
That's a great work.
We can identify the amount of elemental Sulphur either by AAS, CHNS or Wickbold apparatus.I need to estimate the amount of sulphur in sulphide form (present in substrate -solid) and sulphur in sulphate form ( present in liquid).
First of all determine the sulfide or sulfate by wet chemical analysis. Then using the mole percentage calculation you can determine the sulfur content. This is the simplest way and fairly accurate method of doing it, rather than trying to reduce every thing to elemental sulfur and estimating it.
Oxidation of all suphide to suphate and then gravimetric estimation through Barium sulphate is too old but perfect method and simple.Alternatively sulphide can be released in the form of hydrogen sulphide which when passed through lead acetate solution precipitates lead sulphide or as silver sulphide which can be quantitatively estimated by oxidation to sulphate and consequent volumetric estimation of sulphate.
Dear Mouna, there is a couple of methods to measure sulfide. Microbiologists quite often use Cu-based method (CuS formation)/ That is quite quick method and quite sensitive one. But for very precise measurements so-called method of Cline is used.
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