Jennifer R. Verkouteren

Amphibole asbestos from Libby, Montana: Aspects of nomenclature

Abstract Richterite-asbestos and winchite-asbestos are not listed in the federal regulations governing asbestos. However, asbestiform winchite is found in the gangue at the Libby, Montana, vermiculite deposit, where asbestos-related diseases have been reported among the miners and millers. Changing amphibole nomenclature, uncertainties in Fe2+/Fe3+, and natural compositional variability result in samples of the asbestiform amphibole from Libby being variably classified as soda tremolite, richterite, sub-calcic actinolite, and winchite. A classification of winchite-asbestos is assigned for two samples of Libby asbestos analyzed for this report, consistent with the most recent International Mineralogical Association classification system. Although some of the unit-cell parameters and optical properties reported here are distinctive, others are very similar to the tremolite-actinolite series.

Reliability of ion mobility spectrometry for qualitative analysis of complex, multicomponent illicit drug samples

Ion mobility spectrometry (IMS) has been used for trace analysis of illicit drugs, but it can also provide reliable qualitative analysis of bulk forensic drug items, despite the complexity of these samples. The drug/drug and drug/excipient combinations representing over 80% of the samples reported by state and federal forensic laboratories over the past 7 years were compiled from reports of the National Forensic Laboratory Information System (NFLIS). From this set of materials, IMS detection windows were set for eight controlled substances, including methamphetamine, 3,4-methylenedioxymethamphetamine hydrochloride (MDMA), cocaine, heroin, fentanyl, hydrocodone, oxycodone, and alprazolam. The reduced mobilities of the eight controlled substances were measured over an extended period of time to determine variability with respect to the size of the detection windows. Uncertainties in reduced mobilities smaller than 0.001 cm(2)V(-1)s(-1) were obtained, and detection windows were set to between ±0.003 and ±0.005 cm(2)V(-1)s(-1). Reduced mobilities are instrument and operating condition dependent, and must be determined for each instrument. Peak overlaps are observed in the drug/drug combinations, but at least one controlled substance can be detected in each mixture. Excipient concentrations must be quite high (>75 wt%) in binary mixtures to interfere with the detection of the controlled substance. IMS can be used to identify many of the excipients, and can detect multiple (for these samples, as many as 4) substances in complex samples. Over-the-counter (OTC) tablet medications for cold, flu, and allergy relief can be distinguished from tablets containing controlled substances. Bulk materials, including tablets, are sampled simply by using a fine probe to restrict the amount of material transferred to the IMS substrate. IMS represents a distinct advantage over color tests for field analysis of illicit drugs, except in the case of cannabis/THC samples.

A method to determine collection efficiency of particles by swipe sampling

A methodology was developed to evaluate particle collection efficiencies from swipe sampling of trace residues. Swipe sampling is used for many applications where trace residues must be collected, including the evaluation of radioactive particle contamination and the analysis of explosives and contraband at screening checkpoints using ion mobility spectrometry (IMS). Collection efficiencies were evaluated for micrometer-sized polystyrene latex (PSL) spheres with respect to the particle size and mode of deposition, collection trap, surface type and swiping force. Test surfaces containing particles were prepared under controlled conditions and swiped with a reproducible technique that allows for the evaluation of frictional forces. Collection efficiencies were determined by optical imaging and particle counting. Of the two IMS collection traps studied, the polytetrafluoroethylene (PTFE) trap has significantly lower collection efficiencies. This is likely to be due to a combination of texture and composition. The larger (42 µm diameter) particles are collected more efficiently than the smaller (9 µm diameter) particles. Particles in a matrix similar to latent fingerprints are collected more efficiently than dry particles. Applying greater force during swiping does not greatly improve collection efficiencies. This fact, coupled with the observation that many particles are detached but not collected, implies that improvements in collection efficiency are dependent on improvements in adhesion of the particles to the collection surface, rather than larger forces to detach the particles.

The tremolite-actinolite-ferro–actinolite series: Systematic relationships among cell parameters, composition, optical properties, and habit, and evidence of discontinuities

Abstract Unit-cell parameters, optical properties, and chemical compositions have been measured for 103 samples in the tremolite-actinolite-ferro-actinolite series. The average values of the non-essential constituents are: TAl = 0.10(11), CAl = 0.06(6), B(Fe, Mn, Mg) = 0.09(7), BNa = 0.04(5), ANa = 0.09(9), and Cr, Ti, and K ≅ 0. Asbestiform actinolite samples have lower Al contents than massive or “byssolitic” actinolite samples. Unit-cell parameters for end members tremolite and ferro-actinolite based on regressions of the data are: a = 9.841 ± 0.003 Å, 10.021 ± 0.011 Å; b = 18.055 ± 0.004 Å, 18.353 ± 0.018 Å; c = 5.278 ± 0.001 Å, 5.315 ± 0.003 Å; and cell volume = 906.6 ± 0.5 Å3, 944 ± 2 Å3. The changes in a, b, and cell volume with ferro-actinolite substitution are modeled with quadratic functions, and the change in c with ferro-actinolite substitution is modeled with a linear function. There is a positive correlation between c and Al that results in a discrimination between asbestiform and massive or “byssolitic” habits for c and for the refractive indices. The principal refractive indices nγ and nβ are linear with respect to ferro-actinolite substitution, but nα is best modeled by two lines with a change in slope between 26 and 32% ferro-actinolite. Birefringence and extinction angle also change between 26 and 32% ferro-actinolite. The predicted end-member values of the principal refractive indices for tremolite and ferro-actinolite are: nα = 1.602 ± 0.001, 1.661 ± 0.005; nβ = 1.621 ± 0.001, 1.692 ± 0.004; and nγ = 1.631 ± 0.001, 1.700 ± 0.003. There is a discontinuity in a at approximately 11% ferro-actinolite that is accompanied by a drop in Ca. There are also indications of discontinuities in optical properties and c between 26 and 32% ferro-actinolite that may be due to an increase in tschermakite substitution. Both discontinuities are accompanied by a decrease in the relative frequency of natural samples.

Atmospheric identification of active ingredients in over-the-counter pharmaceuticals and drugs of abuse by atmospheric pressure glow discharge mass spectrometry (APGD-MS)†

Atmospheric pressure glow discharge mass spectrometry was used to characterize the active ingredients in pharmaceutical over-the-counter (OTC) drug formulations (Tylenol Allergy, Alka-Seltzer Plus Nighttime, Sudafed, Aleve and Mucinex DM) and drugs of abuse (crack cocaine, methamphetamine, MDMA (ecstasy) and hydrocodone). Material was desorbed and directly ionized under atmospheric conditions by allowing the substance to come in direct contact with the plasma followed by mass spectrometric detection. With this technique, controlled substances and OTC medications were readily distinguished from one another. Characteristic mass spectra were identified for the active ingredients in the OTC and drugs of abuse. Importantly, all drug compounds studied here, both OTC and illicit, demonstrated signals for either molecular ions or protonated molecules as well as fragmentation patterns that are readily identified in the National Institute of Standards and Technology (NIST) electron ionization (EI) mass spectral library. It is believed that this technique holds promise for forensic and law enforcement communities for real-time atmospheric analysis of drugs with database-searchable spectra of controlled substances.

Anomalous optical properties of fibrous tremolite, actinolite, and ferro-actinolite

Abstract The fibrillar growth habit and {100} twinning of fibrous amphiboles tend to produce anomalous optical properties. Commercial amosite and crocidolite always exhibit uniaxial-like optical properties including parallel extinction and two principal indices of refraction. Fibrous members of the actinolite series, however, exhibit a range in optical properties from normal to anomalous. The types of anomalous optical properties that can be displayed by asbestiform members of the actinolite series are described based on a study of twelve samples. One sample displays uniaxial-like properties, nine display partial development of uniaxial-like properties, and two contain fibers with both orthorhombic and monoclinic optical properties. “Byssolitic” samples of the actinolite series, a fibrous non-asbestiform habit, contain fibers that do not go to extinction in sections on or near (010), probably as a result of {100} twinning. Although anomalous optical properties may confound the identification of fibrous amphiboles, in most cases the refractive indices are predictable and can be used for identification. Because of the range in optical properties, especially extinction angle, reliance solely on parallel extinction to distinguish asbestos from non-asbestiform varieties is not recommended. The fibrillar structure, however, remains the hallmark of the asbestiform habit.

Measurement of drug facilitated sexual assault agents in simulated sweat by ion mobility spectrometry

Ion mobility spectrometry has found widespread use for the detection of explosives and illicit drugs. The technique offers rapid results with high sensitivity and little sample preparation. As such, it is well suited for field deployed screening settings. Here the response of ion mobility spectrometers for three drug-facilitated sexual assault (DFSA) agents - flunitrazepam, ketamine, and MDMA - and related metabolites has been studied in the presence of a simulated sweat. While all three DFSA agents present certain challenges for qualitative identification, IMS can provide useful information to guide the early treatment and investigation of sexual assault cases. Used as a presumptive test, the identification of DFSA agents would later require confirmatory analysis by other techniques.

Rapid detection of fentanyl, fentanyl analogues, and opioids for on-site or laboratory based drug seizure screening using thermal desorption DART-MS and ion mobility spectrometry

Fentanyl and fentanyl analogues represent a current and emerging threat in the United States as pure illicit narcotics and in mixtures with heroin. Because of their extreme potency, methods to safely and rapidly detect these compounds are of high interest. This work investigates the use of thermal desorption direct analysis in real time mass spectrometry (TD-DART-MS) and ion mobility spectrometry (IMS) as tools for the rapid and sensitive (nanogram to picograms) detection of fentanyl, 16 fentanyl analogues, and five additional opioids. Competitive ionization studies highlight that detection of these compounds in the presence of heroin is readily achievable, down to 0.1% fentanyl by mass with TD-DART-MS. With IMS, detection of nanogram levels of fentanyl in a binary fentanyl and heroin mixture is possible but can be complicated by decreased resolution in certain commercial instrument models. Modifications to the alarm windows can be used to ensure detection of fentanyl in binary mixtures. Additionally, three complex background matrices (fingerprint residue, dirt, and plasticizers) are shown to have a minimal effect of the detection of these compounds. Wipe sampling of the exterior of bags of questioned powders is shown to be a safe alternative method for field screening and identification, removing the need to handle potentially lethal amounts of material.

Pressure-Sensitive Sampling Wands for Homeland Security Applications

This paper discusses the use of force sensing resistor (FSR) technology integrated into sampling wands used for homeland security applications. FSR-integrated wands can be used for the optimization of wipe sampling of surfaces to facilitate enhanced trace contraband collection. Collection efficiencies during wipe sampling are known to be dependent on the applied force, or pressure, used during sampling. Light-emitting diodes designed to switch from red to green at a defined force threshold of 7 N provide feedback to the operator during sampling. The goal of maintaining forces at or above the threshold was successfully demonstrated by testing with a volunteer population of 22. An additional benefit is the reduction in the variability of the force applied by each operator during sampling. Another focus area is the development of prototype sampling wands that fit in the palm of the hand and other wand modifications that increase the reliability of wipe sampling by registering the placement of the collected sample properly on the wipe. This paper also outlines how an array-based FSR can be used to visualize contact area and pressure during wipe sampling.

Aerosol Collection Efficiency of a Graded Metal-Fiber Filter at High Airflow Velocity (10 m s–1)

A non-woven graded metal-fiber filter was characterized for its collection efficiency as a function of particle size at an airflow velocity of 10 m s −1 . Efficiencies were determined by generating a monodisperse aerosol of polystyrene latex (PSL) spheres and oleic acid liquid particles of measured concentration with and without the filter present. For PSL spheres ≤0.7 μm, the collection efficiencies follow theoretical single-fiber collision efficiency (Ptak and Jaroszczyk 1990). Above 0.7 μm diameter (Stokes number 0.8), PSL collection efficiency exhibits a general decreasing trend with increasing particle size suggesting particle bounce. Although this trend is consistent with measured single-fiber collection (collision and adhesion) efficiency for Stokes numbers in the range of 0.2 to 22 (Rembor et al. 1999; Ptak and Jaroszczyk 1990), the magnitude of the filter efficiency is less. For 1 μm to 4 μm PSL, the average collection efficiency is 0.43 (expanded uncertainty (U) of 0.08, n = 6). In the case of particles having very different surface adhesion, e.g., oleic acid (sticky) aerosol, the collection efficiency for ≥1 μm diameter particles is nearly 1.00. This is in accordance with the theoretical collision efficiency as expected for particles with high adhesion. PSL tests performed on a filter coated with a synthetic-oil (aerosol) deposit (32.9 μg mm −2 ± 0.4 μg mm −2 ) improved the collection efficiency for PSL ≥ 0.7 μm to nearly 1.00. Particles that are deposited by interception-inertial impaction at 10 m s −1 airflow velocity depend on the particle and fiber adhesion properties.