Xác định dư lượng cloramphenicol, florfenicol, thiamphenicol, ofloxacin, ciprofloxacin, enrofloxacin có trong nước thải bằng phương pháp LC-MS/MS

Abstract

A reversed-phase LC-MS/MS method was developed for simultaneous determination of chloramphenicol (CLOR), florfenlcol (FLOR), thiamphenicol (THI), ofloxacin (OFL), ciprofloxacin (CIP), enrofloxacin (ERF) in wastewaters. The method was optimized as follows: Column - Agilent ZORBAX Eclipse Plus (150 mm x 4.6 mm x 3.5 pm); Mobile phase - acetonitrile - methanol - water with formic add (in gradient mode); Flow rate -1.0 mUmin; Sample injection volume -10 pL. Detector -electrospray ionnization source was operated in positive mode, negative mode and multi reaction monitoring (MRM) mode using the transition of m/z 332.29 → 231.08, m/z 362.22 → 261.03, m/z 360.35 → 245.17, m/z 320.16 → 233.01, m/z 321.14 → 152.01, m/z 326.14 → 156.95, m/z 354.14 → 184.98, m/z 356.14 → 335.94 to quantify CIR OFL, ERF, norfloxacin NOR, IS-1), CLOR, chloramphenicol-d5 (CL0R-d₅, IS-2), THI, FLOR, respectively. Validated in observance to the AOAC and EC guideline, the method proved to meet the requirements, with wide linearity range (1-200 ppb) and high correlation coefficient (R² > 0.99), very good accuracy (recovery rate 81.2-109.2%) and intra-day precision (RSD < 6,63%), typical LOD, LOQ values of 0,1-1 ppb and 0.4-4 ppb for these 6 antibiotics. On preliminary practical application of the validated method, about 90% of wastewater samples were revealed to contain measurable concentrations of ciprofloxacin (CIP), enrofloxacin (ERF), florfenicoi (FLOR), thiamphenicol (THI).