Validation of a Rapid Quantitative Method for the Residues of Nitrofuran Metabolites in Loach by Accelerated Solvent Extraction and HPLC Triple Quadrupole Mass Spectrometry

A rapid method using HPLC-MS/MS has been developed for quantitative determination of the metabolites of nitrofurans, namely 3-amino-2-oxazolidone (AOZ), 5-morpholinomethyl-3-amino-2-oxazolidinone (AMOZ), 1-ammino-hydantoin (AHD) and semicarbazide (SEM) in loach. The extraction procedure was founded on simultaneous acidic hydrolysis and derivatization using 2-nitrobenzaldehyde (2-NBA) for 1 hour at $50^{\circ}C$, followed by purification with liquid-liquid extraction. Recovery was evaluated by spiking standards into blank samples at three levels (0.5, 1.0 and $2.0{\mu}g/kg$), and the mean recovery was 75.1-108.1%. Precision values expressed as the relative standard deviation (%RSD) were ${\leq}8.7%$ and ${\leq}8.5%$ for intra-day and inter-day precision, respectively. Linearity was studied in the range of $0.2-20{\mu}g/Kg$ for NBAOZ, $0.8-20{\mu}g/Kg$ for NBAMOZ, $0.2-20{\mu}g/Kg$ for NBAHD, and $0.1-20{\mu}g/Kg$ for NBSEM, and the obtained coefficient correlations (r) were ${\geq}0.99$ for all compounds. Limits of detection (LODs) for the derivatized nitrofuran metabolites were established at $0.06{\mu}g/Kg$ for NBAOZ, $0.24{\mu}g/Kg$ for NBAMOZ, $0.06{\mu}g/Kg$ for NBAHD, and $0.03{\mu}g/Kg$ for NBSEM. Limits of quantification (LOQs) were established at $0.2{\mu}g/Kg$ for NBAOZ, $0.8{\mu}g/Kg$ for NBAMOZ, $0.2{\mu}g/Kg$ for NBAHD, and $0.1{\mu}g/Kg$ for NBSEM. This simplified rapid method for reducing the derivatization and hydrolysis times can be applied to the determination of nitro-furan residues in loach.

미꾸라지에서의 Nitrofuran계 대사물질인3-amino-2-oxazolidone(AOZ), 5-morpholinomethyl-3-amino-2-oxazolidinone(AMOZ), 1-ammino-hydantoin (AHD)와 semicarbazide(SEM)의 잔류량을 검사하기 위해HPLC-MS/MS를 이용한 신속한 정량법이 개발되었다. 2-nitrobenzaldehyde (2-NBA)를 이용해 $50^{\circ}C$에서 1시간 동안 산 가수분해와 유도체화 과정을 거친 뒤에, 액-액 분배로 정제와 추출을 하였다. 회수율은 음성시료에 3가지 농도 0.5, 1.0, $2.0{\mu}g/kg$의 표준액을 첨가하여 평가하였고 평균 회수율은 75.1-108.1% 이었다. 정밀성(%RSD)은 일내 8.7% 이하, 일간 8.5% 이하였다. 직선성은 NBAOZ는 $0.2-20{\mu}g/Kg$, NBAMOZ는 $0.8-20{\mu}g/Kg$, NBAHD는 $0.2-20{\mu}g/Kg$, NBSEM 는 $0.1-20{\mu}g/Kg$ 범위에서 모두 상관계수 0.99이상이었다. 검출한계(LOD)는 NBAOZ $0.06{\mu}g/Kg$, NBAMOZ $0.24{\mu}g/Kg$, NBAHD $0.06{\mu}g/Kg$, NBSEM $0.03{\mu}g/Kg$이었고, 정량한계(LOQ)는 NBAOZ $0.2{\mu}g/Kg$, NBAMOZ $0.8{\mu}g/Kg$, NBAHD $0.2{\mu}g/Kg$, NBSEM $0.1{\mu}g/Kg$ 이었다. 가수분해 및 유도체화 소요시간을 1시간으로 줄여 만든 신속 간편한 이 시험법이 미꾸라지 중 nitrofuran metabolites잔류량 분석에 적합함을 확인할 수 있었다.