Marc A. LeBeau

Recommendations for Toxicological Investigations of Drug-Facilitated Sexual Assaults

The recent increase in reports of drug-facilitated sexual assaults has caused alarm in the general public and prompted forensic toxicologists from across North America to address the toxicological issues surrounding this matter. The authors have developed recommendations and guidelines to inform law enforcement, medical, and scientific personnel of the requirements for performing successful toxicological examinations in cases of drug-facilitated rape.

The role of variations in growth rate and sample collection on interpreting results of segmental analyses of hair

Segmental analysis of hair for drugs, metabolites, and poisons has been widely reported in the scientific literature over the past two decades. Two fundamental assumptions in interpreting results of such analyses are (1) an average linear growth rate of head hair of 1cm/month and (2) that sample collections occur with the hair being cut directly next to the scalp. The purpose of this study was to evaluate the variability associated with growth rate of human head hair, as well as the ability to uniformly collect hair next to the scalp. The results were used to determine how these factors affect the interpretation of results generated in segmental analysis of hair. A thorough literature review was conducted to assess the range of linear growth of human head hair from the vertex posterior and occipital regions. The results were compiled to establish the average (1.06cm/month), as well as the range of possible growth rates of head hair. The range was remarkable and suggests that conclusions based on the 1-cm/month growth rate could be significantly skewed. A separate study was undertaken to evaluate collection of hair next to the scalp. Fourteen individuals were provided oral instructions, as well as a written standard collection procedure for head hair. The experience levels among the collectors varied from novice to expert. Each individual collected hair from dolls with short- and long-hair. Immediately following each collection, the sampling area was evaluated to determine how close to the scalp the cuts were made, as well as the variability in the lengths of hair remaining at the sampled area. From our collection study, we determined that 0.8±0.1cm of hair was left on the scalp after cutting. When taking into account the amount of hair left on the scalp after collecting, the use of a growth rate of 1.06cm/month, and the assumption that it takes two weeks for newly formed hair in the follicle to reach the scalp, we find that the first 1-cm segment of hair typically corresponds to hair formed 1.3±0.2 to 2.2±0.4 months (95% confidence) earlier. The impact of these findings as it relates to the corresponding time for each additional segment is demonstrated. As a result, we recommend that hair collection be delayed 8 weeks after a suspected ingestion to ensure that the sample fully represents the exposure period. The results of this study suggest that the variability in the growth rate of human head hair, as well as the inconsistent collection of hair, significantly affect the interpretation of results from segmental analysis of hair.

Effect of storage temperature on endogenous GHB levels in urine

Because gamma-hydroxybutyrate (GHB) is an endogenous substance present in the body and is rapidly eliminated after ingestion, toxicologists investigating drug-facilitated sexual assault cases are often asked to differentiate between endogenous and exogenous levels of GHB in urine samples. This study was designed to determine the effects of storage temperature on endogenous GHB levels in urine. Specifically, it was designed to ascertain whether endogenous levels can be elevated to a range considered indicative of GHB ingestion. Urine specimens from two subjects that had not been administered exogenous GHB were collected during a 24h period and individually pooled. The pooled specimens were separated into standard sample cups and divided into three storage groups: room temperature ( approximately 25 degrees C), refrigerated (5 degrees C), and frozen (-10 degrees C). Additionally, some specimens were put through numerous freeze/thaw cycles to mimic situations that may occur if multiple laboratories analyze the same specimen. Periodic analysis of the samples revealed increases in the levels of endogenous GHB over a 6-month period. The greatest increase (up to 404%) was observed in the samples maintained at room temperature. The refrigerated specimens showed increases of 140-208%, while the frozen specimens showed smaller changes (88-116%). The specimens subjected to multiple freeze/thaw cycles mirrored specimens that had been thawed only once. None of the stored urine specimens demonstrated increases in GHB concentrations that would be consistent with exogenous GHB ingestion.

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.

Analysis of biofluids for flunitrazepam and metabolites by electrospray liquid chromatography/mass spectrometry.

A rapid and sensitive liquid chromatography/electrospray ionization mass spectrometry (LC/MS) procedure has been developed for the analysis of biofluids containing flunitrazepam and its metabolites. Specimens were spiked with deuterated analogs of the analytes. Urine specimens were enzymatically hydrolyzed and blood specimens were untreated. Extractions were carried out using CleanScreen DAU SPE cartridges. The drugs were separated on a C18 column using a methanol-water-ammonium hydroxide (60:40: 0.03 v/v) mobile phase. After determination of base peaks using full scan mass spectrometry, the mass spectrometry method was optimized to operate in selected-ion monitoring (SIM) mode for the base peak of each analyte. Positive findings were confirmed by LC/MS/MS using the same mobile phase and column. This analytical procedure allows for the detection of low levels of flunitrazepam and metabolites in biofluids. It is useful for ascertaining the role of flunitrazepam in cases of drug-facilitated sexual assault.

Evaluation of Four Fingerprint Development Methods for Touch Chemistry Using Matrix-Assisted Laser Desorption Ionization/Time-of-Flight Mass Spectrometry,†‡

Four preparation techniques for MALDI/TOF mass spectrometry were compared to determine the ability to gather intelligence for investigations through the chemical analysis of latent fingerprints, defined as “touch chemistry.” Compatible fingerprint development processes used for identification along with new techniques are necessary to evaluate touch chemistry. Ten volunteers deposited fingerprints from solvent residues containing drugs and explosives onto microscope slides. The developers included (A) fingerprint powder, (B) MALDI matrix, (C) fingerprint powder and lifting, and (D) cyanoacrylate fuming with fingerprint powder. Qualitative identification was based on ion images and spectra. The highest average detection rates (88%) were found using methods A and B. Methods C (52%) or D (18%) had limited success. Results demonstrate the importance of imaging coupled to extracted mass spectral data in detecting analytes in deposited fingerprints. Overall, the results suggest continued development of touch chemistry applications could prove useful for gathering intelligence and forensically relevant information.

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.