Eshwar Jagerdeo

Screening of Cocaine and Its Metabolites in Human Urine Samples by Direct Analysis in Real-Time Source Coupled to Time-of-Flight Mass Spectrometry After Online Preconcentration Utilizing Microextraction by Packed Sorbent

Microextraction by packed sorbent (MEPS) has been evaluated for fast screening of drugs of abuse with mass spectrometric detection. In this study, C8 (octyl-silica, useful for nonpolar to moderately polar compounds), ENV+ (hydroxylated polystyrene-divinylbenzene copolymer, for extraction of aliphatic and aromatic polar compounds), Oasis MCX (sulfonic-poly(divinylbenzene-co-N-polyvinyl-pyrrolidone) copolymer), and Clean Screen DAU (mixed mode, ion exchanger for acidic and basic compounds) were used as sorbents for the MEPS. The focus was on fast extraction and preconcentration of the drugs with rapid analysis using a time-of-flight (TOF) mass spectrometer as the detector with direct analysis in a real-time (DART) source. The combination of an analysis time of less than 1 min and accurate mass of the first monoisotopic peak of the analyte and the relative abundances of the peaks in the isotopic clusters provided reliable information for identification. Furthermore, the study sought to demonstrate that it is possible to quantify the analyte of interest using a DART source when an internal standard is used. Of all the sorbents used in the study, Clean Screen DAU performed best for extraction of the analytes from urine. Using Clean Screen DAU to extract spiked samples containing the drugs, linearity was demonstrated for ecgonine methyl ester, benzoylecgonine, cocaine, and cocaethylene with average ranges of: 65–910, 75–1100, 95–1200, and 75–1100 ng/mL (n = 5), respectively. The limits of detection (LOD) for ecgonine methyl ester, benzoylecgonine, cocaine, and cocaethylene were 22. 9 ng/mL, 23. 7 ng/mL, 4. 0 ng/mL, and 9.8 ng/mL respectively, using a signal-to-noise ratio of 3:1.

An automated SPE/LC/MS/MS method for the analysis of cocaine and metabolites in whole blood

As laboratories are called upon to develop novel, fast, and sensitive methods, here we present a completely automated method for the analysis of cocaine and its metabolites (benzoylecgonine, ecgonine methyl ester, ecgonine and cocaethylene) from whole blood. This method utilizes an online solid-phase extraction (SPE) with high performance liquid chromatographic separation and tandem mass spectrometric detection. Pretreatment of samples involve only protein precipitation and ultracentrifugation. An efficient online solid-phase extraction (SPE) procedure was developed using Hysphere MM anion sorbent. A gradient chromatography method with a Gemini C6-Phenyl (50mmx3.00mm i.d., 5microm) column was used for the complete separation of all components. Analysis was by positive ion mode electrospray ionization tandem mass spectrometry, using multiple reaction monitoring (MRM) to enhance the selectivity and sensitivity of the method. For the analysis, two MRM transitions are monitored for each analyte and one transition is monitored for each internal standard. With a 30-microL sample injection, linearity was analyte dependent but generally fell between 8 and 500ng/mL. The limits of detection (LODs) for the method ranged from 3 to 16ng/mL and the limits of quantitation (LOQs) ranged from 8 to 47ng/mL. The bias and precision were determined using a simple analysis of variance (ANOVA: single factor). The results demonstrate bias as <7%, and %precision as <9% for all components at each QC level.

A semi-automated solid-phase extraction liquid chromatography/tandem mass spectrometry method for the analysis of tetrahydrocannabinol and metabolites in whole blood†

Marijuana is one of the most commonly abused illicit substances in the USA, making cannabinoids important to detect in clinical and forensic toxicology laboratories. Historically, cannabinoids in biological fluids have been derivatized and analyzed by gas chromatography/mass spectrometry (GC/MS). There has been a gradual shift in many laboratories towards liquid chromatography/mass spectrometry (LC/MS) for this analysis due to its improved sensitivity and reduced sample preparation compared with GC/MS procedures. This paper reports a validated method for the analysis of Delta(9)-tetrahydrocannabinol (THC) and its two main metabolites, 11-nor-9-carboxy-Delta(9)-tetrahydrocannabinol (THC-COOH) and 11-hydroxy-Delta(9)-tetrahydrocannabinol (THC-OH), in whole blood samples. The method has also been validated for cannabinol (CBD) and cannabidiol (CDN), two cannabinoids that were shown not to interfere with the method. This method has been successfully applied to samples both from living people and from deceased individuals obtained during autopsy. This method utilizes online solid-phase extraction (SPE) with LC/MS. Pretreatment of samples involves protein precipitation, sample concentration, ultracentrifugation, and reconstitution. The online SPE procedure was developed using Hysphere C8-EC sorbent. A chromatographic gradient with an Xterra MS C(18) column was used for the separation. Four multiple-reaction monitoring (MRM) transitions were monitored for each analyte and internal standard. Linearity generally fell between 2 and 200 ng/mL. The limits of detection (LODs) ranged from 0.5 to 3 ng/mL and the limits of quantitation (LOQs) ranged from 2 to 8 ng/mL. The bias and imprecision were determined using a simple analysis of variance (ANOVA: single factor). The results demonstrate bias as <7%, and imprecision as <9%, for all components at each quantity control level.

An improved method for the analysis of GHB in human hair by liquid chromatography tandem mass spectrometry.

The abuse of gamma-hydroxybutyric acid (GHB) and its suspicion in cases of suspected drug-facilitated sexual assault is of keen interest to forensic toxicology laboratories. This paper reports an extraction, separation and detection procedure for GHB in hair utilizing a combination of liquid-liquid extraction and solid-phase extraction using ethyl acetate and Oasis Max(®) cartridge, respectively, after the hair sample was digested. Analysis was by LC-MS-MS using a gradient separation on an Acclaim(®) Trinity(TM) P1 column performing three multiple-reaction monitoring (MRM) transitions each for GHB and its internal standard. The procedure was validated over a range from 0.4 to 50 ng/mg with estimated limit of detection (LOD) of 0.33 and an administratively set limit of quantitation (LOQ) of 1.2 ng/mg. Twenty hair specimens collected from individuals with no known exposure to GHB were analyzed for matrix interferences and to establish initial background levels of GHB. A wide range of endogenous GHB levels were observed in these samples (from less than the LOQ to 4.4 ng/mg). The results suggest the need for additional studies to better establish the full range of endogenous GHB levels in hair and that extreme caution is required in interpreting GHB findings in hair samples.

Rapid analysis of forensic samples using an atmospheric solid analysis probe interfaced to a linear ion trap mass spectrometer

RATIONALE This paper highlights the simplicity of interfacing an Atmospheric Solid Analysis Probe (ASAP) to a Linear Ion Trap Mass Spectrometer and shows that this technique can be used for the rapid generation of high-quality data from a range of sample types with minimal or no sample preparation. METHODS For a solid sample or surface deposit, the process entails rubbing a capillary melting tube a few times on the sample to transfer material to the capillary surface and then introducing it into the source of the mass spectrometer. Similarly, for a liquid sample, a capillary tube is dipped into the sample to just coat the surface or a few microliters may be applied to the tip of a capillary before being analyzed by Atmospheric Pressure Chemical Ionization in both positive and negative mode. RESULTS A rodenticide containing brodifacoum, black tar heroin and its impurities (morphine, codeine, noscapine, papaverine, and monoacetylmorphine), crack cocaine and 1-methylaminoanthraquinone dyestuff were successfully analyzed directly without any sample preparation. All compounds were detected using full scan mass spectrometry (MS), followed by confirmation by MS/MS. Preliminary results suggest that this technique could be used for quantitation. CONCLUSIONS Interfacing the ASAP to an ion trap mass spectrometer allows the ability to perform full scan, MS(n) experiments, and rapid positive/negative switching from a single sample introduction. Because of these features, this instrument is very useful for rapid, routine analysis and for confirmation with the use of in-house MS/MS libraries.