ABSTRACT
@#A deuterated internal standard quantitative analysis method based on liquid-liquid extraction-ultra performance liquid chromatography-tandem mass spectrometry (LLE-UPLC-MS/MS) for simultaneous determination of 10 illicit drugs in wastewater was established.Wastewater samples were concentrated by liquid-liquid extraction with dichloromethane: ethyl acetate (1∶1), and separated by a linear gradient of 0.1% formic acid-5 mmol/L ammonium formate aqueous solution and acetonitrile on a C18 column. The samples were then detected by ESI positive ion mode and multiple reaction monitoring mode (MRM) for quantitative analysis.All analytes had a good linear relationship (r ≥ 0.995 7) within the range of their respective standard curves; the limit of quantification was 1 ng/L (except amphetamine at 2.5 ng/L); the relative recovery rate ranged from 96.36% to 106.43%, and the intra- and inter-day precisions were less than 4.70%.This method is accurate, reliable and reproducible, and is suitable for the quantitative determination of 10 illicit drugs in wastewater.It is also suitable for wastewater with complex matrixes that affect solid phase extraction and enrichment.It provides a new analytical method for real-time monitoring of drug abuse.
ABSTRACT
In this study,we developed a novel on-line solid phase extraction (SPE)-ultra-high-performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS)-based analytical method for simulta-neously quantifying 12 illicit drugs and metabolites (methamphetamine,amphetamine,morphine,co-deine,6-monoacetylmorphine,benzoylecgonine,3,4-methylenedioxymethamphetamine,3,4-methylenedioxyamphetamine,cocaine,ketamine,norketamine,and methcathinone) and cotinine(COT) in wastewater samples.The analysis was performed by loading 2 mL of the sample onto an Oasis hydrophilic-lipophilic balance cartridge and using a cleanup step (5％ methanol) to eliminate interference with a total run time of 13 min.The isotope-labeled internal standard method was used to quantify the target substances and correct for unavoidable losses and matrix effects during the on-line SPE process.Typical analytical characteristics used for method validation were sensitivity,linearity,precision,repeatability,recovery,and matrix effects.The limit of detection (LOD) and limit of quantification (LOQ)of each target were set at 0.20 ng/L and 0.50 ng/L,respectively.The linearity was between 0.5 ng/L and 250 ng/L,except for that of COT.The intra-and inter-day precisions were ＜10.45％ and 25.64％,respec-tively,and the relative recovery ranged from 83.74％ to 162.26％.The method was used to analyze various wastewater samples from 33 cities in China,and the results were compared with the experimental re-suits of identical samples analyzed using off-line SPE.The difference rate was between 19.91％and-20.44％,and the error range could be considered acceptable.These findings showed that on-line SPE is a suitable alternative to off-line SPE for the analysis of illicit drugs in samples.
ABSTRACT
@#A quantitative analysis method based on solid phase extraction-ultra performance liquid chromatography-tandem mass spectrometry (SPE-UPLC-MS/MS) for simultaneous determination of illicit drugs and their metabolites in wastewater was established. Samples filtered at pH of 2 and spiked with internal standard were loaded to Oasis Prime MCX cartridges for solid-phase extraction. The samples were washed with 4 mL of methanol and eluted with 4 mL of 5% ammonia in acetonitrile before reconstituting with 0.1% formic acid/water solution. ZORBAX Eclipse Plus C18 column was used for chromatography, and gradient elution was performed with 0.1% formic acid/water solution and acetonitrile as mobile phase. The samples were then detected by electrospray ionization (ESI) in positive ion mode, and multiple reaction monitoring mode (MRM) was adopted for quantitative analysis. All analytes had a good linear relationship (r ≥ 0.993 2) within the range of their respective standard curve; the limit of quantification was 1 ng/L (except amphetamine at 2.5 ng/L); the extraction recovery ranged from 82.13% to 99.96%; and the intra- and inter-day precisions were less than 9.43%. The method is accurate, reliable and reproducible, and is suitable for the quantitative determination of illicit drugs and their metabolites in wastewater and can provide an analytical method for real-time monitoring of drug abuse.