Determination of Butyltins in Sea Water by Gas Chromatography with Flame Photometric Detection

Use of a gas chromatograph with a flame‐photometric detector (GC‐FPD) is described to determine butyltin compounds in sea water. The butyltins in an acidified water sample (pH 3.0) are first complexed with tropolone, followed by solid‐phase extraction (SPE) with a tropolone‐treated C 18 cartridge. HCI at a small concentration is then added to the concentrated SPE eluate before GC analysis. This procedure is simple and off‐column derivatization of analytes is not required. The organotins, viz. mono‐, di‐ and tributyltin, are separated as their respective chlorides on a capillary column (HP‐1) and are detected with a flame‐photometric detector and an interference filter at 610 nm. Recoveries of the three butyltin species are quantitative (> 90%). Based on a sea water sample 200‐mL, the detection limits for mono‐, di‐ and tributyltin are 6,4 and 3 ng tin L −1 , respectively. This method is applied to analysis of trace butyltins in various samples of sea water.