in determination H2S in crud oil we used Borax solution 30% to extract H2S from crud oil to borax then acidify with HCl then titration with iodine and thiosulfate sodium.
i want to know why i use Borax ?because i can use NaOH or another base.
The described method of H2S determination in crude oil is called redox titration. In this case the method of iodomery was used. It is possible to determine reductants by this method. We add an excessive amount of oxidator (Iodine) to our solution. Than the excess amount of Iodine must be titrated by sodium thiosulfate. But concerning this case we must previously extract the tested matter (H2S) from crude oil. For this aim the Borax is being used as a buffer. Borax promotes H2S extracting from crude oil for further analysis. In general you can use the other bases however borax can have some hidden benefits, so try to use the another bases on test samples.