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- Determination of Ketamine and Norketamine in hair samples using MEPS as sample clean-upPublication . Simão, Ana Y.; Oliveira, Patrik; Rosendo, Luana M.; Rosado, Tiago; Gallardo, Eugenia; Andraus, Maristela; Barroso, MárioIntroduction and Aim: The use of hair samples to determine ketamine (K) and its metabolite, norketamine (NK), has been studied by several authors, using different clean-up approaches. However, microextraction by packed sorbent (MEPS), a miniaturized form of the classic solid-phase extraction has not been applied to date for the purpose. Therefore, a method to determine K and NK in hair samples was developed, optimized, and validated using MEPS as sample clean-up. Materials & Methods: Hair samples were scissor-cut into small fragments, and rinsed with methanol to remove dirt and externally deposited material. Following an overnight incubation with methanol at 65 ºC (no stirring), the compounds were analysed by GC-MS/MS without the need of derivatization procedures; MEPS conditions were: conditioning (5 x 250 µL of methanol and 4 x 250 µL of deionized water); load (10 x 150 µL of hair extract); washing (50 µL of 0.1% acetic acid and 50 µL of 10% methanol); and elution (100 µL of 3% ammonium hydroxide in methanol). Results & Discussion: The procedure resulted in acceptable recoveries, 39-61% for K and 32-43% for NK, and allowed reaching limits of quantification (LOQs) of 50 pg/mg for both analytes. The analytical method presented acceptable accuracy and precision with coefficients of variation typically lower than 15% and BIAS within ± 15%, except at the LOQ (20%). The method was successfully applied to 2 authentic samples, and ketamine concentrations were below 0.05 and 0.18 ng/mg. Norketamine was not detected. Conclusions: This work is the first analytical method using MEPS coupled to GC-MS/MS for the determination of K and NK in hair samples. Following a comparison with a SPE-based method using authentic samples, it was considered rapid and suitable for routine analysis. Acknowledgments: FCT (UIDB /00709/2020 and UIDP/00709/2020). A.Y. Simão acknowledges the PhD fellowship from FCT (2020.09070.BD).
- Development and optimization of a new method to determine antidepressants in oral fluid by microextraction by packed sorbent and analysis by GC-MS/MSPublication . Soares, Sofia; Rosado, Tiago; Barroso, Mário; Gallardo, EugeniaBetween 2013 and 2016, the consumption of antidepressants doubled in Portugal, with around 30 million packages of medication for depression, anxiety and other mental health problems dispensed annually. This phenomenon has even given rise to several alerts, which was highlighted in the 2017 report of the National Program for Mental Health, as Portugal has one of the highest rates of mental illness in Europe1. Therapeutic drug monitoring is well established for a small number of drugs, namely for those where a direct relationship between concentration and pharmacological effect at the site of action exists, which in turn is predictably reflected in the response. Drug concentrations in the various biological fluids are used in conjunction with other clinical observation measures to assess the patient's condition, and further support the individualization of therapy. Within this group of drugs targeted for monitoring are antidepressants. In recent years, oral fluid has gained more and more importance in the field of therapeutic drug monitoring, as a non-invasive and painless alternative to traditionally sampled specimens (e.g. blood, plasma). MEPS is a miniaturized solid-phase extraction (SPE) and therefore has a great advantage in the reduced operating volumes and consequently lower amounts of sample and organic solvents are required. As a result, MEPS decreases the time required for extraction, clean-up and concentration of analytes. This is the first work that uses MEPS as sample preparation technique for the determination of antidepressants and metabolites in oral fluid samples (250 µL). The simple extraction procedure proved to be efficient, requiring only 250 µL of biological sample, making it an excellent alternative for the determination of these compounds in routine clinical and forensic toxicology laboratories and for therapeutic monitoring purposes.
- Otimização de uma metodologia por microextração em seringa empacotada e cromatografia gasosa-espetrometria de massa em tandem para a identificação de arilciclohexaminas em amostras de cabeloPublication . Oliveira, Patrik; Simão, Ana Y.; Rosendo, Luana M.; Pedro, Soraia; Rosado, Tiago; Andraus, Maristela; Barroso, Mário; Gallardo, EugeniaAs novas substâncias psicoativas (NPS) têm vindo a tornar-se um problema cada vez mais um problema de saúde pública. Em Portugal, a ketamina (KET) entrou para a lista de NSP com o Decreto-Lei nº 54/2013. Inicialmente sintetizada com o intuito de substituir a fenciclidina (PCP) como anestésico, acabou por ser usada recreativamente devido aos seus efeitos alucinogénios e estimulantes. Recentemente, a esketamina (análogo da KET) foi introduzida com finalidade terapêutica no tratamento de depressão major refractária a outra terapêutica. Para distinguir o consumo terapêutico do recreativo é necessário que existam métodos que para a sua deteção e quantificação. Neste trabalho foi desenvolvido e otimizado um método para a deteção de KET e seu metabolito (norketamina – NK) em amostras de cabelo com recurso à microextração em seringa empacotada (MEPS) e cromatografia de gases acoplada à espetrometria de massa em tandem (GC-MS/MS). (1) Foi desenvolvido um método analítico para a determinação de KET e NK em amostras de cabelo com recurso à MEPS; (2) A GC-MS/MS foi crucial para deteção inequívoca dos analitos, aumentando a sensibilidade e seletividade do método; (3) As recuperações obtidas são adequadas e foram alcançados LODs baixos (alcançando os cut-offs (0,2 ng/mg) propostos pela Society of Hair Testing) (4) Primeiro método analítico que permite a determinação de KET e NK em amostras de cabelo com recurso a MEPS e GC-MS/MS