[Determination of 3-nitropropionic acid in poisoning samples by ultra-performance liquid chromatography-tandem mass...

An ultra-performance liquid chromatography-tandem mass spectrometric method was established for determination of 3-nitropropionic acid of sugarcane, sugarcane bagasse, vomit, serum and urine.

The 3-nitropropionic acid in poisoning samples was extracted by acetonitrile in super-sonic instrument. The supernatant was cleaned up with PSA column and eluted with 10% ammonia water-methanol (10: 90, V/V), then the purified solution was concentrated by nitrogen, dissolved with water (containing 0.4% formic acid) and cleaned by 0.22 μm millipore filter. The filtrate was detected by ultra-performance liquid chromatography-tandem mass spectrometry, identified by electrospray ionization (ESI) in negative mode using multiple reaction monitoring, and quantified with external standards of sample matrix matching. The sample extract was separated on an acquity BEH C18 column (2.1 mm x 150 mm x 1.7 μm) by gradient elution in 10 minutes with acetronitrile-water as mobile phase.

The calibration curves of 3-nitropropionic acid residues showed good linearity in the range of 1.0 - 50 μg/kg with correlation coefficient of 0.9993 or 0.9998. The detection limits of the method were from 0.06 μg/kg to 0.30 μg/kg, and limits of quantitation ranged from 0.20 μg/kg to 1.0 μg/kg. The recoveries of three spiking levels (1.0, 10.0 and 100.0 μg/kg) ranged from 86.9% to 102.0%, and the relative standard deviations of 1.80%- 4.19% were obtained.

The method for determination of 3-nitropropionic acid in poisoning samples by UPLC-MS/MS is of operation convenience, less interference from impurities and good accuracy, which could provide evidence and treatment for mouldy sugarcane poisoning.