Forensic Analysis of Polymeric Carpet Fibers Using Direct Analysis in Real Time Coupled to an AccuTOF™ Mass Spectrometer.

Polymeric fibers are encountered in numerous forensic circumstances. This study focused on polymeric carpet fibers most encountered at a crime scene, which are nylons, polyesters and olefins. Analysis of the multiple polymer types was done using Direct Analysis in Real Time (DART™) coupled to an Accurate time-of-flight (AccuTOF™) mass spectrometer (MS). A DART gas temperature of 275 °C was determined as optimal. Twelve olefin, polyester, and nylon polymer standards were used for parameter optimization for the carpet fiber analysis. A successful identification and differentiation of all twelve polymer standards was completed using the DART-AccuTOF™. Thirty-two carpet samples of both known and unknown fiber composition were collected and subsequently analyzed. All samples with known fiber compositions were correctly identified by class. All of the remaining carpet samples with no known composition information were correctly identified by confirmation using Fourier-transform infrared spectroscopy (FTIR). The method was also capable of identifying sub-classes of nylon carpet fibers. The results exhibit the capability of DART-AccuTOF™ being applied as an addition to the sequence of tests conducted to analyze carpet fibers in a forensic laboratory.

Differentiating Nylons Using Direct Analysis in Real Time Coupled to an AccuTOF Time-of-Flight Mass Spectrometer.

Nylons are chemically synthesized polymers that are used in a variety of ways. This study differentiates multiple nylon types using direct analysis in real time (DART) coupled with an orthogonal-acceleration time-of-flight (oaTOF) mass spectrometer (MS). Seven closely related nylon standards were studied. A DART helium gas temperature of 275 °C was chosen as an optimum for the analysis of nylons. Use of collision induced dissociation (CID) to induce fragmentation increased the power of discrimination. All seven nylon standards were successfully differentiated and identified using DART-MS.

Use of DART-TOF-MS for Screening Drugs of Abuse.

Screening is an integral component of an analytical scheme to identify the presence of controlled substances in submissions to the crime laboratory. Many techniques are utilized, including color tests, thin-layer chromatography, and ultraviolet spectroscopy. While these are useful techniques to guide the examiner, all will, at best, categorize the material into a broad group of compounds. Direct Analysis in Real Time (DART), coupled with a time-of-flight (TOF) mass spectrometer, is an emerging technique that yields highly definitive screening data leading to the identity of controlled substances present in a case sample. Sample preparation is quick and simple and run times are typically only a few minutes. Collected data will allow the examiner to determine appropriate standards for confirmation, making the overall analysis much more efficient. Presented here is a guide to using this technique for the screening of case submissions for controlled substances.

Detection of the Duquenois-Levine chromophore in a marijuana sample.

The Duquenois-Levine test for tetrahydrocannabinol (THC) has been used in the forensic science community for over 80 years. This three-part color test is one of many tests used to confirm the presence of THC. In recent years, there have been accusations that this test is not specific enough to use as the sole means of conviction and there is no proof the color produced is from the presence of THC. A structure for the chromophore of the test was proposed by Dr. Dale Forrester in his doctoral dissertation pertaining to the analysis of the Duquenois test using THC standards. Through the use of the AccuTOF-DART system and an Agilent triple quadrupole mass spectrometer, further elucidation of the proposed chromophore was performed on extracts of marijuana samples.

Pharmaceutical identifier confirmation via DART-TOF.

Pharmaceutical analysis comprises a large amount of the casework in forensic controlled substances laboratories. In order to reduce the time of analysis for pharmaceuticals, a Direct Analysis in Real Time ion source coupled with an accurate mass time-of-flight (DART-TOF) mass spectrometer was used to confirm identity. DART-TOF spectral data for pharmaceutical samples were analyzed and evaluated by comparison to standard spectra. Identical mass pharmaceuticals were differentiated using collision induced dissociation fragmentation, present/absent ions, and abundance comparison box plots; principal component analysis (PCA) and linear discriminant analysis (LDA) were used for differentiation of identical mass mixed drug spectra. Mass assignment reproducibility and robustness tests were performed on the DART-TOF spectra. Impacts on the forensic science community include a decrease in analysis time over the traditional gas chromatograph/mass spectrometry (GC/MS) confirmations, better laboratory efficiency, and simpler sample preparation. Using physical identifiers and the DART-TOF to confirm pharmaceutical identity will eliminate the use of GC/MS and effectively reduce analysis time while still complying with accepted analysis protocols. This will prove helpful in laboratories with large backlogs and will simplify the confirmation process.

Validation of thin layer chromatography with AccuTOF-DART™ detection for forensic drug analysis.

Thin layer chromatography (TLC) is a technique that is commonly employed in the forensic drug analysis of pharmaceutical preparations. Detection is typically accomplished using various visualization spray reagents. Conventional gas chromatography-mass spectrometry (GC-MS) analysis is typically performed to confirm the TLC results. Depending on the drugs tested and the instrument conditions required, this confirmation can take up to an hour to complete. Direct analysis in real time (DART™) is an ionization source, coupled to an accurate-mass time-of-flight mass spectrometer that has the capability to ionize materials under ambient conditions. To streamline analysis, the combination of TLC with DART™ detection is proposed to screen and subsequently identify drug compounds, all from the same TLC plate. DART™ confirmations of TLC analyses take <10 min to complete and compare favorably to GC-MS in sensitivity and selectivity. This study validates the use of TLC-DART in the forensic identification of the components of several pharmaceutical preparations.

Purification of pharmaceutical preparations using thin-layer chromatography to obtain mass spectra with Direct Analysis in Real Time and accurate mass spectrometry.

Forensic analysis of pharmaceutical preparations requires a comparative analysis with a standard of the suspected drug in order to identify the active ingredient. Purchasing analytical standards can be expensive or unattainable from the drug manufacturers. Direct Analysis in Real Time (DART™) is a novel, ambient ionization technique, typically coupled with a JEOL AccuTOF™ (accurate mass) mass spectrometer. While a fast and easy technique to perform, a drawback of using DART™ is the lack of component separation of mixtures prior to ionization. Various in-house pharmaceutical preparations were purified using thin-layer chromatography (TLC) and mass spectra were subsequently obtained using the AccuTOF™- DART™ technique. Utilizing TLC prior to sample introduction provides a simple, low-cost solution to acquiring mass spectra of the purified preparation. Each spectrum was compared against an in-house molecular formula list to confirm the accurate mass elemental compositions. Spectra of purified ingredients of known pharmaceuticals were added to an in-house library for use as comparators for casework samples. Resolving isomers from one another can be accomplished using collision-induced dissociation after ionization. Challenges arose when the pharmaceutical preparation required an optimized TLC solvent to achieve proper separation and purity of the standard. Purified spectra were obtained for 91 preparations and included in an in-house drug standard library. Primary standards would only need to be purchased when pharmaceutical preparations not previously encountered are submitted for comparative analysis. TLC prior to DART™ analysis demonstrates a time efficient and cost saving technique for the forensic drug analysis community. Copyright © 2011 John Wiley & Sons, Ltd.

Development and validation of AccuTOF-DART™ as a screening method for analysis of bank security device and pepper spray components.

Analysis of bank security devices, containing 1-methylaminoanthraquinone (MAAQ) and o-chlorobenzylidenemalononitrile (CS), and pepper sprays, containing capsaicin, is a lengthy process with no specific screening technique to aid in identifying samples of interest. Direct Analysis in Real Time (DART™) ionization coupled with an Accurate Time of Flight (AccuTOF) mass detector is a fast, ambient ionization source that could significantly reduce time spent on these cases and increase the specificity of the screening process. A new method for screening clothing for bank dye and pepper spray, using AccuTOF-DART™ analysis, has been developed. Detection of MAAQ, CS, and capsaicin was achieved via extraction of each compound onto cardstock paper, which was then sampled in the AccuTOF-DART™. All results were verified using gas chromatography coupled with electron impact mass spectrometry.

Validation of the direct analysis in real time source for use in forensic drug screening.

The Direct Analysis in Real Time (DART) ion source is a relatively new mass spectrometry technique that is seeing widespread use in chemical analyses world-wide. DART studies include such diverse topics as analysis of flavors and fragrances, melamine in contaminated dog food, differentiation of writing inks, characterization of solid counterfeit drugs, and as a detector for planar chromatography. Validation of this new technique for the rapid screening of forensic evidence for drugs of abuse, utilizing the DART source coupled to an accurate mass time-of-flight mass spectrometer, was conducted. The study consisted of the determination of the lower limit of detection for the method, determination of selectivity and a comparison of this technique to established analytical protocols. Examples of DART spectra are included. The results of this study have allowed the Virginia Department of Forensic Science to incorporate this new technique into their analysis scheme for the screening of solid dosage forms of drugs of abuse.

Detection of gamma-hydroxybutyric acid in various drink matrices via AccuTOF-DART.

A new screening method for detecting gamma-hydroxybutyric acid (GHB) in drink matrices, using the IonSense, Inc. (Saugus, MA) direct analysis in real time (DART) ion source coupled to a JEOL exact mass time-of-flight mass spectrometer (AccuTOF), was validated and compared with the current screening methodology. The DART ion source allows for analysis of samples under ambient conditions with little to no sample preparation. Fifty drink specimens were spiked at levels of 1, 2, 3, and 4 mg/mL GHB, and analyzed on the AccuTOF-DART. Positive detection of GHB occurred for each of the samples at each concentration level, giving 100% accuracy for the samples tested. Twenty-five of the 50 drink specimens were spiked at 1 mg/mL GHB and tested using a color test known as the GHB Color Test #3. Only two of these 25 specimens tested positive for the presence of GHB, giving only 8% accuracy. Implementation of this new methodology as a screening tool for GHB analysis will quickly eliminate negative specimens allowing the examiner to focus analysis time on those that screened positive.