UPLC-MS/MS 测定海水、悬浮颗粒物及沉积物中 18 种藻毒素

A method was established for the simultaneous detection of 18 marine phycotoxins by ultrahigh performance liquid chromatography－tandem mass spectrometry (UPLC－MS/MS) combined with solid phase extraction, including azaspiracids (AZAs), brevetoxins (BTXs), Pacific ciguatoxins (P－CTXs), dinophysistoxins (DTXs), gymnodimine (GYM) maitotoxin3 (MTX3), okadaic acid (OA), pectenotoxin2 (PTX2), spirolide1 (SPX1) and yessotoxins (YTXs) etc. Seawater (1 L) or the ultrasonic extracts of suspended particulate matter or sediment (1 g) was extracted with solid phase extraction cartridges (Agilent Bond Elut C₁₈, 500 mg/6 mL), and then 10% glycerol－methanol was added to the eluent to reduce the loss of target toxins. Water was the aqueous phase and 95% acetonitrile/water was the organic phase, both of which contained 0. 1% formic acid and 2 mmol/L ammonium formate. A Phenomenex Kinetex C₁₈ column (100 mm × 2. 1 mm i. d., 1. 7 µm) was used to separate the phycotoxins in six minutes, and then the target analytes were detected by UPLC－MS/MS in multiple reaction monitoring mode. The external standard method was used for the quantitation of 18 phycotoxins. The correlation coefficients of standard curves were 0. 991 1－0. 999 9. The quantitation limits of the methed for 18 phycotoxins ranged from 0. 05 to 250 pg/L (or pg/g). The matrix-spiked recoveries for 18 phycotoxins ranged from 77. 4% to 119%, with the relative standard deviations of 1. 1%－15%. Ten phycotoxins were detected in seawater from the Pearl River Estuary, with the predominant PTX2 of 36. 6－7 900 pg/L．MTX3 concentrations ranging from 0 to 262 pg/L was monitored for the first time. With good sensitivity and precision, this method can satisfy the requirements for simultaneous determination of 18 phycotoxins in seawater, suspended particulate matter and sediment.