简介: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 简介: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.
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