Luna 3 m c8 2 100 column

Acrolein exposure was measured as its stable metabolite, 3-hydroxylpropyl mercapturic acid (3-HPMA), using an adaptation of a published LC-MS/MS method [17 ]. Calibration curves were prepared in 250 μl urine aliquots using authentic 3-HPMA, with d6-3-HPMA as an internal standard. Samples were assayed using a Sciex 4000 MS/MS interfaced with an Agilent 1260 HPLC; separation was achieved on a Phenomenex Luna 3 µm C8(2) 100 Å column with isocratic elution [0.5% acetic acid in water (90%) and acetonitrile (10%)]. Check standard recoveries ranged from 109% to 117%, and the LOQ (limit of quantitation) for 3-HPMA was 0.275 ng/ml (ppb).

Exposure to the phenoxyherbicide 2,4-D was measured as its soil metabolite, 4-chlorophenol (4-CP) [18 ,19 ], which is mutagenic to mammalian cells in vitro [20 ]. Urine samples were assayed for 4-CP using a previously published LC-MS/MS method [21 ]. Urine samples (1.0 ml) were spiked with d4-4-CP as an internal standard and were acid hydrolyzed to release glucuronide conjugates. The LC-MS/MS system included a Sciex 4000 MS/MS interfaced with an Agilent 1260 HPLC. Separation in the LC was achieved on a Phenomenex Luna 3 µm C8(2) 100 Å column. Check standard recoveries ranged from 71% to 120%, with an LOQ of 0.50 ng/ml (ppb).