A DUAL-PLATFORM GC-MS/MS AND LC-MS/MS STRATEGY FOR THE TOXICOLOGICAL MONITORING OF SIX EMERGING NEW PSYCHOACTIVE SUBSTANCES (NPS): FIT-FOR-PURPOSE VALIDATION IN HUMAN URINE
ILINCA-MIHAELA MARANDIUC 1,2,3, LĂCRĂMIOARA VIOLETA TOPOLICEANU 2,3 , ANDREEA CAMELIA HÎRJĂU 2,3, IRINA-MARIA TOPOLICEANU 4, DANIELA ELENA POPA 1* , ANDREEA-LETIȚIA ARSENE 1 , ALIN NICOLESCU 4
1 Faculty of Pharmacy, “Carol Davila” University of Medicine and Pharmacy, Bucharest, Romania
2 Cantacuzino National Institute for Medical-Military Research and Development, Bucharest, Romania
3 Floreasca Emergency Clinical Hospital, Bucharest, Romania
4 Faculty of Medicine, “Carol Davila” University of Medicine and Pharmacy, Bucharest, Romania
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Clinical toxicology laboratories require robust and sensitive analytical methods to address the increasing prevalence of new psychoactive substances (NPS). This study developed and validated two complementary analytical methods, gas chromatog- raphy-tandem mass spectrometry (GC-MS/MS) and liquid chromatography-tandem mass spectrometry (LC-MS/MS), for the quantitative analysis of six key NPS in human urine, including α-pyrrolidinovalerophenone (α-PVP), 4-methylethcathinone (4- MEC), 3',4'- methylenedioxypyrovalerone (MDPV), 3,4 – methylenedioxy- alpha- pyrrolidinobutiophenone (MDPB), N-(2- Methoxybenzyl)-4-iodo-2,5-dimethoxyphenethylamine (25-NBOMe) and 4-fluoromethcathinone (4-FMC). Both methods were validated according to established guidelines, assessing parameters such as linearity, sensitivity, precision, and accuracy. Both GC-MS/MS and LC-MS/MS methods demonstrated excellent linearity with coefficients of determination (R2) above 0.99. However, the LC-MS/MS method proved to be significantly more sensitive and accurate. It achieved a limit of quantification (LOQ) of 1 µg/L, a substantial improvement over the 200 µg/L LOQ of the GC-MS/MS method. Despite the quantitative limitations imposed by higher bias, the GC-MS/MS framework maintains its procedural significance, serving as a vital tool for the confirmatory identification of these emerging NPS. These parallel analytical trajectories act as complementary frameworks, delivering an empirical evaluation of their deployment in clinical practice for thorough toxicological surveillance.
