Hi Nataly,

The form of sulfur depends on the type of pesticide. Sulphur can be present as elemental sulfur, as a sulfate or in an organic compound (for example the herbicides ethofumesate or Sulfonylureas). Sulfur is also present in natural waters (generally as sulfate or within dissolved organic matter). Chlorine in pesticides is present in organic compounds (and there is a whole class of organochlorine pesticides - many of the persistent such as DDT, Dieldrin and Heptachlor). You can measure the total S and Cl in the sample but it will not tell you if these come from Pesticides or natural sources. It is best to look for compounds of interest that may contain Cl or S. GC ECD and GC-MS are used for Organochlorine pesticides. HPLC / LC-MS may also be useful for some of the sulfur containing herbicides.

these elements are attached to organic compound and one of the most prudent method in Gas Chromatography (GC). The form used is a function of the the type of incenticide that you which to produce

Thank you.

One more thing, do you know of any specific method for measuring the total sulfur and chlorine? The methods I found were based on using special kits. I want to see if there is any developed method for the total amounts and not just specific forms of the elements.

Total Cl and total S can be measured by ICP-OES, but the contribution of pesticides to the total amounts of Cl and S will be so minor compared to the natural background.

Dear Nataly,

Dr. Andrew has nicely explained the topic (forms of Sulfur and Chlorine in pesticides and the methods of determination).

For measurement of water parameter, you first refer to ASTM standards. See the link for "List of water testing standards developed by ASTM" then read the particular standard for understanding the method of testing. Read also a good paper on sulfur.

https://www.astm.org/Standards/water-testing-standards.html

http://www.sciencedirect.com/science/article/pii/0003267092850182

Best wishes

As well as the US Standards recommended by Dr Batabyal there may be French standard methods (Association Française de Normalisation AFNOR) or International ISO standards (though they may be the same as the ASTM).

Thank you, I will see what will work best for my case.