DETERMINATION OF ORGANOTINS BY MICRO-LIQ

2.1 This method provides reversed-phase micro-liquid chromatographic (µLC) and electrospray (ES) mass spectrometric (MS) conditions for the detection of the target analytes. 2.1.1 Sample extracts can be analyzed by direct injection into the electrospray (though interference is possible) or through a liquid chromatographic-electrospray interface. 2.1.2 A gradient elution program is used on the chromatograph to separate the compounds. 2.1.3 Quantitative analysis may be performed by µLC-ES-ITMS, using an external standard approach. µ-LC-ES-ITMS detection is to be performed in the positive ionization mode, with either a ion trap mass spectrometer, or single-quadrupole mass spectrometer. 2.1.4 In some cases, the electrospray interface may introduce variability that leads to less precise quantitation. 2.2 Prior to analysis, appropriate sample preparation techniques must be used. 2.2.1 Two-liter water samples are prepared first acidifying the waters with 12 N hydrochloric acid (HCl) and then the waters are extracted through pre-prepared solid-phase extraction (SPE) discs. 2.2.2 Tissue samples (e.g., fish, brain), are extracted by using a solvent mixture of hexane:acetic acid:tropolone (99:1:0.1 v/v). After sonication is completed, the sample is adjusted to pH 2 with a small quantity of 12N HCl. The acidified sample is then centrifuged for approximately thirty minutes.