Determination of selected organoarsenic compounds by SPME/GC-MS in aquatic samples

A gas chromatography with mass spectrometry was developed for the determination of selected organoarsenic compounds, for example, monomethylarsonic acid, dimethylarsinic acid, phenylarsonic acid, nitarsone and roxarsone, in aquatic environment.For the analysis by gas chromatography, analytes was derivatized with 1,3-propanedithiol.The cyclic dithiaarsenoline formed was extracted from the sample matrix by solid-phase microextraction (SPME).The extraction studies were carried out on different types of extraction fibers such as polyacrylate, polydimethylsiloxane-modified divinylbenzene, carboxenpolydimethylsiloxane, divinylbenzene carboxen polydimethylsiloxane under different conditions.The optimized SPME conditions employed a 65 µm polydimethylsiloxane divinylbenzene fiber, derivatization reaction temperature of 60°C and fiber equilibration time of 30 min.The method allows for the simultaneous determination of monomethylarsonic acid, dimethylarsenic acid, phenylarsonic acid, roxarsone and nitarsone.The repeatability of the analytical method is in the range from 0.78% to 3.23%, and the limits of determination ranging from 0.35 to 5.88 µg L -1 , depending on the compound.The method was applied to determine an organoarsenic compounds in mining water and wastewater from metallurgy of non-ferrous metals industry.