Friday May 4th – Presentations

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Characterization of plasma- and laser-based ambient ionization techniques for forensic analysis

Kenyon Evans-Nguyen, Gaston Merideth II, Abigail Smola, and Kelsey May

The University of Tampa, Tampa, FL

08:30 AM
Analytical Chemistry

Ambient ionization mass spectrometry is a powerful technology for forensic analysis, particularly for drugs and explosives. Given the simple and rapid nature of the technique, it is promising for on-site analysis of explosive devices. Most efforts in ambient ionization focus on organic analysis. While many high explosives are organic, more common explosives are inorganic. This talk will focus on the development of ambient ionization techniques amenable to organic and inorganic analysis, as well as elemental analysis with application to explosives. The suitability of Direct Analysis in Real Time (DART), Low Temperature Plasma (LTP), and microwave jet plasmas for organic, inorganic, and elemental analysis is being characterized. Additionally, the use of lasers in concert with these techniques to enhance surface desorption is being studied. Model explosive mixtures are being analyzed as well as "thermometer" ions, which provide insight into the energy being imparted by ionization. The data yielded by thermometer ion spectra can help to predict the expected extent of fragmentation that can be expected for the labile bonds in explosives.

Preliminary Characterization of Sexual Assault Lubricants: Comparison Between DART-TOFMS, GC-MS, and FT-IR

Caterina R. Vadell-Orsini, Brooke R. Baumgarten, Mark Maric, Candice M. Bridge

National Center for Forensic Science, University of Central Florida

09:05 AM
Analytical Chemistry

Unfortunately, sexual assaults are a reality in today's society. Increasing use of condoms reduces potential of recovering DNA evidence, and a novel approach for the analysis of other trace evidence is required. The characterization and classification of lubricants is a relatively new approach for analyzing unknown trace evidence that could be collected from the crime scene or the victim.

In this study, 20 samples from different sexual lubricant manufacturing types were tested: water-based, silicone-based, oil-based, and organic/edible lubricants, and personal hygiene products which could also be used in sexual assaults. Instrumental methods were developed for direct analysis in real time-time of flight mass spectrometry (DART-TOFMS), gas chromatography-mass spectrometry (GC-MS) and Fourier transform infrared spectroscopy (FTIR). Analytical protocols were designed to increase the identification of unique components in these lubricants to develop a classification scheme for unknown samples.

Neat lubricants, as well as solvent extracts, were analyzed in both positive and negative ionization modes using DART-TOFMS in replicates of five. Neat lubricants and extracts were also analyzed via FTIR in triplicate, and extracts were analyzed by GC-MS in triplicate. Multivariate statistical techniques were used to identify unique markers that describe each class within the larger dataset. Classification schemes were developed for each instrument individually.

The outcomes of the classification schemes are expected to separate the different manufacturing types into groups, and sub-classes within each manufacturing type. The classification schemes developed from this preliminary study will affect the forensic trace evidence community by aiding in future exploitation of evidence found at a crime scene based on the data, thus providing investigative leads and innovative techniques in the analysis of trace evidence.

UPLC-MS/MS analysis of Kratom products and components

Bonnie A. Avery,1 Abhisheak Sharma,1 Alicia G. Lydecker,2 Kavita M. Babu,2 Edward W. Boyer,2 Christopher R. McCurdy3

1Department of Pharmaceutics, University of Florida, Gainesville, FL 32610, Division of Medical Toxicology, 2Department of Emergency Medicine, University of Massachusetts Medical School Worcester, MA 01655 3Department of Medicinal Chemistry, University of Florida, Gainesville, FL 32610

09:25 AM
Analytical Chemistry

Aims: Kratom (Mitragyna speciosa), a plant native to Southeast Asia, has been used for centuries for its stimulant and opium-like effects. Mitragynine and 7- hydroxymitragynine, are the alkaloids thought to be responsible for Kratom's biologic and psychoactive profile, and likely contribute to its problematic use. In this study, we compared the pure isolate to that of an aqueous tea extract of Kratom in pharmacokinetic studies utilizing rats. We also purchased several commercially available Kratom products for analysis looking for evidence of probable adulteration.

Methods: A UPLC-MS/MS method was developed for simultaneous quantification of mitragynine and 7-hydroxymitragynine in methanol extract of commercial Kratom supplements. Rat pharmacokinetic studies were conducted using mitragynine and an equivalent amount of mitragynine in the Kratom tea extract at a dose of 10 mg/kg I.V. and 20 mg/kg P.O.

Results: The bioavailability of mitragynine, when given as tea extract, was 36% compare to the mitragynine having absolute bioavailability of 21%. The Cmax and AUC of the tea extract were found to be significantly higher when compared to the mitragynine alone (830 ng/mL and 245181 ng×hr/mL). The renal clearance of the mitragynine (tea extract) I.V. and oral were 0.013 ± 0.002 and 0.025 ± 0.008 mL/min/kg and the renal clearance when mitragynine was administered I.V and orally were 0.021 ± 0.0052 and 0.07 ± 0.009 mL/min/kg. Also, the analysis of the commercial product reveled that multiple Kratom products had concentrations of 7-hydroxymitragynine that are substantially higher than those found in raw M. speciose leaves.

Conclusions: Mitragynine (tea extract) was found to have better oral bioavailability and kinetic profile compared to mitragynine. From the commercial Kratom products tested, some were found to contain artificially elevated concentrations of 7-hydroxymitragynine, the alkaloid responsible for M. speciosa's concerning mechanistic and side effect profile. This describes a unique form of product adulteration.

Supported by: Center of Research Excellence in Natural Products Neuroscience (CORE-NPN), Grant Number P20GM104932, which is funded by the National Institute of General Medical Sciences (NIGMS) at the National Institutes of Health (NIH) as one of its Centers of Biomedical Research Excellence (COBRE).

Detection of Adulterants in Drug Screening Analysis

Bianca Olivieri 

Mark Maric Ph.D.

Candice Bridge Ph.D.

Bianca Olivieri- University of Central Florida Chemistry Department
Mark Maric Ph.D. - National Center for Forensic Science
Candice Bridge Ph.D. - University of Central Florida Chemistry Department /National Center for Forensic Science

10:15 AM
Analytical Chemistry

Drug abuse has been problematic for centuries; however, the technology to detect drugs and their metabolites in bodily fluids has only been available for less than 50 years.1 To detect the use of illicit drugs in urinalysis, testing typically begins with a screening technique in the form of an immunoassay, such as Enzyme-Linked Immunosorbent Assay (ELISA). Although the response accuracy of immunoassays has increased, it remains only 95% accurate for urine screenings, which may be effectively lowered with the addition of adulterants into the urine matrix.2 To counteract a potential false-negative result, analysts will often use adulterant test strips to detect the presence of additional products. An understanding of this screening technique and the influence of adulterants on accurate results is crucial for workplace drug testing, criminal proceedings and the compliance of court probations.

In this study approximately thirty urine samples were obtained via volunteers under UCF IRB No: SBE-16-12568. Included with the samples were completed surveys detailing drug use, the frequency of stated drug use, and other contributing factors. Based on the provided information, samples were identified containing known types of illicit drugs and their metabolites (i.e. THC, cocaine, amphetamines, and benzodiazepines). No known samples contained traces of α-PVP, therefore a clean urine sample was taken and spiked with an α-PVP standard. Urine samples were then adulterated at set concentrations of 5, 10, 25, and 50 % v/v or w/v. Adulterants in this study included: bleach, vinegar, eye drops, Drano®, nitrite, table salt, and hand sanitizer. The adulterated and unadulterated samples were then analyzed via ELISA protocol. Results with ELISA revealed that certain adulterants (e.g. bleach, eye drops, Drano®) consistently decreased the detected concentration of drug metabolites to below cut-off thresholds. In conjunction, adulterant test strips AdultaCheck® 6 (AC6) and Intect™ 7 (I7), were utilized to determine if and at what concentration the adulterants could be detected. Data has revealed that the majority of the adulterants were unable to be detected at a low 5 % v/v adulteration level. This is a cause of concern, due to the ability of these adulterants to drastically decrease the drug/metabolite concentration using ELISA. The combination of these results suggest that a new urinalysis technique needs to be identified in order to effectively detect the presence of drug metabolites in the case of adulterant addition.

Keywords: ELISA, Adulterant Test Strips, Urinalysis

1.Bennett, J. B., Introduction. In Preventing Workplace Substance Abuse: Beyond Drug Testing to Wellness, Bennett, J. B.; Lehman, W. E. K., Eds. American Psychological Association: Washington, DC, 2003

2.Schütz, H.; Paine, A.; Erdmann, F.; Weiler, G.; Verhoff, M. A., Immunoassays for drug screening in urine. Forensic Science, Medicine, and Pathology 2006, 2 (2), 75-83.

 

 

A gold nanoparticle/aptamer-based multi-channel paper microfluidic device designed for the scheduled drugs.

Ling Wang, Bruce McCord

Florida International University

10:35 AM
Analytical Chemistry

Designed aptamer has been developed to successfully identify some drugs of abuse in the last years.  Gold nanoparticles are usually used as a colorimetric detection or an electrical detection of drugs in the solutions.  These tests are based on the operations of chemical reactions, so they require the special knowledge of the chemical reactions.  We have been working on an alternative platform for the gold nanoparticles/ aptamers detection based on paper microfluidic devices.  Paper microfluidic devices are prepared with a wax-ink printer, thermal laminator, chromatography paper, gold nanoparticles and aptamers.  We have created a chip with a multiple-channel design which utilized the gold nanoparticles and special aptamers as a ready-to-use format.  In the field, samples are dissolved in a carrier solvent in vials and then applied to the paper just before the analysis.  The drug sample in the moving solution moved through the channel via capillary actions, reacted with the designed aptamers, and changed the color of gold nanoparticles with salted-induced aggregations.  Aptamers in each channel react with the target drug and the gold nanoparticles area turn from red to black indicating the presence of the target drug.  The entire process takes 5-10 minutes.  The devices can be used in different conditions where the suspected powders need the identification.   These devices are easy to prepare and inexpensive to operate without the special knowledge or training.

DEVELOPMENT AND VALIDATION OF COMPUTATIONAL MODELS FOR FIRE DEBRIS ANALYSIS

Michael E. Sigman and Mary R. Williams

National Center for Forensic Science, University of Central Florida, PO Box 162367, Orlando, FL 32816.

10:55 AM
Analytical Chemistry

Detecting an ignitable liquid residue in fire debris is a challenging data analysis problem. Partial combustion and pyrolysis of substrate materials in a fire produce many chemical compounds also found in commercial ignitable liquids. The fire often leads to partial evaporation of the ignitable liquid, resulting in a modified chromatographic profile. The highly varied background signal and evaporation effects of the fire combine to enhance the data analysis challenge.  The ASTM E1618 standard method facilitates the classification of unevaporated ignitable liquids into a set of classes and categories based on chemical composition, product use, production method, or miscellaneous. However, fire debris data analysis methods based on ASTM E1618 that rely on visual pattern recognition are subjective and lead to categorical decisions and statements devoid of any reference to evidential value. Computational methods, such as support vector machines, discriminant analysis, k-nearest neighbors and others, can be used to identify ignitable liquid residues in the presence of a highly varied background signal. These methods can also provide a measure of the strength of the evidence. Research results on the use of computational pattern recognition methods for the detection of ignitable liquid residue in fire debris samples will be presented. The computational results will be evaluated by performance metrics, including receiver operating characteristic analysis, detection error tradeoff, Tippett plots and empirical cross entropy. Calculation and reporting of likelihood ratios will be discussed based on the computational methods.