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

Abstract: 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.     

Analysis of alprazolam by DART-TOF mass spectrometry in counterfeit and routine drug identification cases

The high prevalence of alprazolam abuse translates to an increased workload for crime laboratories in characterizing seized tablets. These tablets may originate as diverted pharmaceuticals or counterfeited mimics, so efficient analytical techniques should provide confirmatory data while minimizing destruction of evidence. We offer the first report of a validated forensic method for confirming alprazolam tablets by direct analysis in real time-time of flight (DART-TOF) mass spectrometric analysis. This technique provides rapid identification of target analytes with minimal sample preparation, allowing direct analysis in the atmospheric sample gap. Selectivity is achieved through high resolution and mass accuracy, unique ion fragments, and chlorine isotopic ratios. This method utilizes fragmentation in two separate voltage functions to observe the alprazolam pseudo molecular ion at 309.09070 using 40 V and major ion fragments of 281.07197 and 205.07657 at 120 V. These parameters allow our laboratory to confirm alprazolam tablets efficiently, without compromising quality forensic standards.     

Quick Screening of Crystal Methamphetamine/Methyl Sulfone Exhibits by Raman Spectroscopy

Abstract: The analysis of mixtures of “crystal meth” (usually comprised of methyl sulfone [MS] and methamphetamine [MA]) by gas chromatography‐mass spectrometry (GCMS) is routine in many forensic drug laboratories. The utilization of Raman spectroscopy for the identification of such mixtures quickly and without the need for a separation technique is discussed. Samples were dissolved in water and Raman spectra of the resulting aqueous solutions were collected. By comparing these spectra to spectra of methylsulfone and MA mixtures of known composition, an indication of the composition of the sample can be obtained in only a few minutes. This spectral comparison also can be used as a semi‐quantitative analysis of MA concentrations in such exhibits.     

论侦查实验风险及其防范

风险在经济学中有着广泛的研究,而在侦查学领域尚未引起足够的重视。事实上,人们从事的各种社会活动都或多或少存在一定的风险。侦查实验是一种法定侦查措施,在实践中有广泛的应用,但目前对其理论尚缺乏全面的研究。从风险这一角度对侦查实验进行研究,提出防范风险的对策,对科学合理地进行侦查实验具有重要意义。     

Doubling Down: Inequality in Responsiveness and the Policy Preferences of Elected Officials

Is bias in responsiveness to constituents conditional on the policy preferences of elected officials? The scholarly conventional wisdom is that constituency groups who do not receive policy representation still obtain some level of responsiveness by legislators outside of the policy realm. In contrast, we present a theory of preference‐induced responsiveness bias where constituency responsiveness by legislators is associated with legislator policy preferences. Elected officials who favor laws that could disproportionately impact minority groups are also less likely to engage in nonpolicy responsiveness to minority groups. We conducted a field experiment in 28 US legislative chambers. Legislators were randomly assigned to receive messages from Latino and white constituents. If legislators supported voter identification laws, Latino constituents were less likely to receive constituency communications from their legislators. There are significant implications regarding fairness in the democratic process when elected officials fail to represent disadvantaged constituency groups in both policy and nonpolicy realms.     

DOES IMPRISONMENT ALTER THE LIFE COURSE? EVIDENCE ON CRIME AND EMPLOYMENT FROM A NATURAL EXPERIMENT

Ex‐prisoners consistently manifest high rates of criminal recidivism and unemployment. Existing explanations for these poor outcomes emphasize the stigmatizing effects of imprisonment on prisoners seeking postrelease employment as well as the deleterious effects of imprisonment on prisoners’ attitudes and capabilities. However, these explanations must be distinguished from selection effects in the criminal sentencing process, which also could explain some or all of these poor outcomes. To distinguish between criminogenic and selection explanations for ex‐prisoners’ postrelease experience, I analyze data from a natural experiment in which criminal cases were assigned randomly to judges with sizable sentencing disparities. Using these exogenous sentencing disparities, I produce unbiased estimates of the causal effects of imprisonment on the life course. The results of this analysis suggest that selection effects could be sufficiently large to account for prisoners’ poor postrelease outcomes because judges with large sentencing disparities in their use of imprisonment had similarly high caseload unemployment and criminal recidivism rates.     

Raman Spectroscopy as a Simple,Rapid, Nondestructive Screening Test for Methamphetamine in Clandestine Laboratory Liquids

Raman spectroscopy has found increased use in the forensic controlled substances laboratory in recent years due to its rapid and nondestructive analysis capabilities. Here, Raman spectroscopy as a screening test for methamphetamine in clandestine laboratory liquid samples is discussed as a way to improve the efficiency of a laboratory by identifying the most probative samples for further workup among multiple samples submitted for analysis. Solutions of methamphetamine in ethanol, diethyl ether, and Coleman fuel were prepared in concentrations ranging from 0.5% to 10% w/v, and Raman spectra of each were collected. A concentration‐dependant Raman peak was observed at 1003 per cm in each solution in 4% w/v and greater solutions. Case samples were analyzed and also found to reliably contain this diagnostic peak when methamphetamine was present. The use of this diagnostic indicator can save the forensic controlled substances laboratory time and materials when analyzing clandestine laboratory liquid submissions.     

In search of enduring information effects: Evidence from a ten-week panel experiment

The extent to which the electorate uses issue information to update their candidate evaluations over the course of political campaigns has often raised questions about citizen competence. Using a ten-week panel experiment designed to capture the low-information context of most congressional races this study contributes to our understanding of when and by what processes issue information produces enduring effects. Findings reveal that when voters need to assess an ideologically moderate candidate, they rely less on partisan cues but instead of storing issue information in long-term memory – either via a memory-based or on-line process – considerations in short-term memory remained one of the most powerful predictors of candidate evaluation, particularly when new issue information deviated from partisan norms.     

How best to open up local democracy? A randomised experiment to encourage contested elections and greater representativeness in English parish councils

Interventions aimed at increasing the supply and representativeness of elected officials range from facilitative to the formally authorised. This paper reports on a field experiment aimed at testing the effect of facilitative approaches at the local level based on a collaboration between parish councils and the research team. We randomly allocated 818 parish council clerks across five counties in Southern England, either to receive information and the opportunity for member training for recruitment, or not to receive this contact. We investigated the effect of this intervention on political recruitment. Despite evidence of an effect on use of social media, our results suggest that there are significant institutional and structural barriers to participation in local politics that cannot easily be overcome using facilitative measures.