ABSTRACT
In utero exposure to marijuana may cause various short- and long-term health problems, such as stillbirth, low birth weight and decreased cognitive function. Detection of in utero marijuana exposure with a relatively new specimen type, umbilical cord tissue, can be used to plan treatment and guide social management. In this study, a liquid chromatography-tandem mass spectrometry (LC-MS-MS) assay was developed for the simultaneous identification of four cannabinoids in umbilical cord tissue, including ∆9-tetrahydrocannabinol (THC), 11-nor-9-carboxy-∆9--THC (THC-COOH), 11-hydroxy-∆9-THC (11-OH-THC) and cannabinol (CBN). Within- and between-run imprecision, accuracy, linearity, sensitivity, carryover, recovery, matrix effects and specificity were evaluated using drug-free umbilical cord tissue spiked with non-deuterated and deuterated standards. Calibration curves were reproducible and linear (r > 0.995) for all four analytes in the range of 0.2 ng/g lower limit of quantitation (LLOQ) and 30 ng/g upper limit of quantitation (ULOQ). Total imprecisions (% coefficient of variation) were 7.8% (THC), 13.3% (THC-COOH), 11.8% (11-OH-THC) and 10.6% (CBN) at low QC (n = 15, 0.25 ng/g), and were 7.2% (THC), 10.0% (THC-COOH), 9.5% (11-OH-THC) and 5.8% (CBN) at high QC (n = 15, 4 ng/g), respectively. No interfering substances were identified, and no carryover was observed. The average accuracies (N = 25) were 94-95%. The average recoveries observed for THC, THC-COOH, 11-OH-THC and CBN were 74, 82, 58 and 86%, respectively. By analyzing authentic clinical specimens that had been previously tested for cannabinoids by enzyme-linked immunoassay, positive and negative result agreements were 100 and 53.8%. In summary, the presented method can be used for the assessment of in utero exposure to four common cannabinoids.
Subject(s)
Cannabinoids/metabolism , Chromatography, Liquid , Marijuana Abuse/metabolism , Marijuana Smoking/metabolism , Substance Abuse Detection/methods , Tandem Mass Spectrometry , Umbilical Cord/metabolism , Biomarkers/metabolism , Calibration , Cannabinol/metabolism , Chromatography, Liquid/standards , Dronabinol/analogs & derivatives , Dronabinol/metabolism , Enzyme-Linked Immunosorbent Assay , Female , Humans , Limit of Detection , Marijuana Abuse/complications , Marijuana Abuse/diagnosis , Marijuana Smoking/adverse effects , Pregnancy , Reference Standards , Reproducibility of Results , Substance Abuse Detection/standards , Tandem Mass Spectrometry/standardsABSTRACT
In this study, a quantitative polarity switching liquid chromatography coupled with a tandem mass spectrometer (LC-MS/MS) method was developed to detect and quantify cocaine and metabolites (cocaethylene, benzoylecgonine and meta-hydroxybenzoylecgonine), phencyclidine (PCP) and barbiturates (phenobarbital and butalbital) in meconium. Accuracy and precision samples at 0.0125% and 75% of the upper limit of quantitation (ULOQ) were analyzed in triplicate over 5 days with accuracy above 84% and average %CV values below 11%. Within-run (n = 15) and between-run (n = 15) %CV values were ≤5%. Analytical measurement ranges were reproducible and linear (R ≥ 0.995) for cocaine and metabolites (20-2,000 ng/g), PCP (10-1,000 ng/g) and barbiturates (50-5,000 ng/g). Accuracy of 100 ± 20% was observed at (the limits of detection) 10 ng/g for cocaine and metabolites, 2.5 ng/g for PCP and 25 ng/g for barbiturates. No carryover was observed at 2X ULOQ and no interfering substances were identified. Sample preparation recoveries were 53-83%. Fifty-one authentic patient samples previously characterized correlated with the newly developed test having R2 values ≥0.996. This combined method allows accurate quantitation of the targeted drugs in a complex matrix while decreasing sample preparation and analysis time with reduced sample volume. Clinical data and positivity rates were similar to previously published positivity rates. Validation data and positivity rate agreement signifies a reliable and robust assay.
Subject(s)
Barbiturates/analysis , Chromatography, Liquid , Cocaine-Related Disorders/diagnosis , Cocaine/metabolism , Meconium/chemistry , Pentobarbital/analysis , Phencyclidine Abuse/diagnosis , Phencyclidine/analysis , Substance Abuse Detection/methods , Tandem Mass Spectrometry , Biotransformation , Cocaine-Related Disorders/metabolism , Female , Humans , Limit of Detection , Phencyclidine Abuse/metabolism , Predictive Value of Tests , Pregnancy , Reproducibility of Results , WorkflowABSTRACT
Bioorthogonal conjugation reactions such as strain-promoted azide-alkyne cycloaddition (SPAAC) have become increasingly popular in recent years, as they enable site-specific labeling of complex biomolecules. However, despite a number of improvements to cyclooctyne design, reaction rates for SPAAC remain significantly lower than those of the related copper-catalyzed azide-alkyne cycloaddition (CuAAC) reaction. Here we explore micellar catalysis as a means to increase reaction rate between a cyclooctyne and hydrophobic azide. We find that anionic and cationic surfactants provide the most efficient catalysis, with rate enhancements of up to 179-fold for reaction of benzyl azide with DIBAC cyclooctyne. Additionally, we find that the presence of surfactant can provide up to 51-fold selectivity for reaction with a hydrophobic over hydrophilic azide. A more modest, but still substantial, 11-fold rate enhancement is observed for micellar catalysis of the reaction between benzyl azide and a DIBAC-functionalized DNA sequence, demonstrating that micellar catalysis can be successfully applied to hydrophilic biomolecules. Together, these results demonstrate that micellar catalysis can provide higher conjugation yields in reduced time when using hydrophobic SPAAC reagents.
