GeneMarker® HID: A reliable software tool for the analysis of forensic STR data

Abstract: GeneMarker^® HID was assessed as a software tool for the analysis of forensic short tandem repeat (STR) data and as a resource for analysis of custom STR multiplexes. The software is easy to learn and use, and includes design features that have the potential to reduce user fatigue. To illustrate reliability and accuracy, STR data from both single‐source and mixture profiles were analyzed and compared to profiles interpreted with another software package. A total of 1898 STR profiles representing 28,470 loci and more than 42,000 alleles were analyzed with 100% concordance. GeneMarker HID was also used to successfully analyze data generated from a custom STR multiplex, with simplified and rapid implementation. Finally, the impact of the user‐friendly design features of the software was assessed through a time scale study. The results suggest that laboratories can reduce the time required for data analysis by at least 25% when using GeneMarker HID.     

Population genetic data for 17 non-CODIS STR loci for the Saudi Arabian population using the SureID®23comp Human Identification Kit

Our previous work focused on validation the SureID 23comp Human Identification Kit (Health Gene Technologies, China), following the minimum criteria for validation recommended by the European Network of Forensic Science Institutes (ENFSI) and the Scientific Working Group on DNA Analysis Methods (SWGDAM) using 500 samples from the population of Saudi Arabia. The kit genotypes 22 STRs, 17 of which are non-CODIS, and Amelogenin. The validation tests showed that it has the potential to increase the power of testing in complex cases.In this paper, the allele frequency data, common forensic parameters for the 17 non-CODIS STR loci are presented. We found the majority of loci had an excess of homozygosity in the data set, which is most likely explained by the relatively high levels of consanguinity in the population of Saudi Arabia.     

Rapid screening for the detection and differentiation of γ-hydroxybutyrate using ion chromatography

The analysis of gamma-hydroxybutyric acid (GHB) is problematic because it is hygroscopic, it lacks a good UV chromophore, and it undergoes heat-induced cyclization. This paper presents a new method utilizing ion-exchange chromatography (IC) with conductivity detection. The simple sample preparation, rapid analysis time, and inorganic anion detection capabilities are all advantages over the current methods. The detection of inorganic salts (formed during GHB synthesis) gives insight into the synthetic route utilized and can aid in drug seizure comparison. The developed method has a detection limit for GHB anions of 0.57 mg/L and chloride of 0.22 mg/L. A comparison of this technique with a current gas chromatography-mass spectrometry technique is presented, and a t-test found that the two methods' results are not statistically different at the 99.9% confidence level demonstrating the merits of this fast, simple, and informative IC method as a routine screening tool.     

Development and validation of the AmpFℓSTR® Identifiler® Direct PCR Amplification Kit: a multiplex assay for the direct amplification of single-source samples

Abstract: The AmpF?STR^® Identifiler^® Direct PCR Amplification Kit is a new short tandem repeat multiplex assay optimized to allow the direct amplification of single‐source blood and buccal samples on FTA^® card without the need for sample purification and quantification. This multiplex assay has been validated according to the FBI/National Standards and SWGDAM guidelines. Validation results revealed that slight variations in primer concentration, master mix component concentration, and thermal cycling parameters did not affect the performance of the chemistry. The assay’s sensitivity was demonstrated by amplifying known amounts of white blood cells spotted onto FTA^® cards, and the assay’s specificity was verified by establishing minimal cross‐reactivity with nonhuman DNA. No effect on the age of the sample stored on the FTA^® substrate was observed and full concordance was established in the population study. These findings of the validation study support the use of the Identifiler^® Direct Kit for forensic standards and database samples genotyping.     

Simultaneous detection and image capture of biological evidence using a combined 360° camera system with single wavelength laser illumination

Forensic investigators frequently utilise light sources to detect and presumptively identify biological evidence. The instrumentation typically deploys single or multiple wavelength exposures at various intensities, which interact with constituents of biological material, initiating fluorescence or improving contrast between the material and substrate. Documentation using sketches and/or photographic approaches follows detection, which are essential for scene reconstruction. Recent research has demonstrated the simultaneous detection and capture of biological evidence using a 360° camera system combined with an alternate light source exhibiting broad wavelength ranges of light. Single wavelength light sources reportedly offer enhanced sensitivity, due to the increased light intensity and narrower bandwidth of light, although their combined use with a 360° camera system has not yet been explored.Samples of human blood, semen, saliva, and latent fingermarks were deposited on to a variety of substrates. A 360° camera system combined with a laser light source was used to detect and capture the samples. Ten participants were asked to detect the samples on images of the substrates without ground truth knowledge. It was possible to detect and capture biological evidence, although success varied according to substrate colour and light intensity. Advantageously, presumptive screening for biological fluids and the simultaneous location and visualisation of such evidence as part of a 360° panorama of the scene for contextual purposes was permitted. There was no fluorescent response from the fingermarks, although the oblique lighting effects appeared sufficient to aid mark detection in some circumstances. The use of single wavelength illumination clearly facilitates identification of a range of forensically important material. When coupled with a 360-degree camera, this allows for simultaneous identification and recording of such evidence in the context of the whole environment.     

Application of LC−QTOF/MS for the validation and determination of organic explosive residues on Ionscan® swabs

The identification and confirmation of trace explosive residues along with potential precursors and degradation products require a comprehensive laboratory analysis procedure. This study presents the determination of organic explosives consisting of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), 2,4,6-trinitrotoluene (TNT), 2,4,6,N-tetranitro-N-methylaniline (Tetryl), 1,3,5-trinitrobenzene (1,3,5-TNB) and pentaerythritol tetranitrate (PETN) by a high-resolution liquid chromatography quadrupole time-of-flight mass spectrometry (LC−QTOF/MS). The qualitative information including retention time, collision energy, precursor ions, and characteristic fragmentation pattern of each explosive were collected using an atmospheric pressure chemical ionization (APCI) in negative ion mode. The separation efficiency among five compounds was greatly achieved in this study. Four real explosive samples consisting of TNT, RDX, PETN and Tetryl and 12 Ionscan® quality control swabs from the Royal Thai Army were also tested to validate and verify the viability of the GC–MS method used to validate results from an Ionscan® system. The results showed that LC−QTOF/MS is a powerful technique for the identification and confirmation of thermally unstable organic explosives on Ionscan® swabs compared to a conventional GC−MS technique.     

Comparative performance of the Phadebas® Forensic Press Test at room temperature and 37 °C for the detection of saliva stains on fabric exhibits

The Phadebas® Forensic Press Test (PFPT) is an enzyme-based colorimetric test used to visualise and locate latent saliva stains on forensic exhibits. The test relies upon the presence of the enzyme α-amylase which is present in high levels in saliva. Even though the optimal in vitro temperature for α-amylase activity is 37 °C, the PFPT manufacturer’s protocol specifies that the PFPT should be carried out at room temperature (RT). In this study, we compared the performance of the PFPT at RT and 37 °C using combinations of four fabric types (cotton, polyester, acrylic and a cotton/polyester blend), three saliva dilutions (neat, 1:10 and 1:100) and stains aged for four time periods (1 day, 1 week, 1 month and 3 months). The intensity of the PFPT colour reactions at RT and 37 °C were not statistically different across all fabric types, saliva concentrations and stain ages, indicating that maximum sensitivity and performance of the PFPT can be achieved at RT.     

Cross-reactivities of various phenethylamine-type designer drugs to immunoassays for amphetamines, with special attention to the evaluation of the one-step urine drug test Instant-View™, and the Emit® assays for use in drug enforcement

Cross-reactivities of 76 kinds of phenethylamine-type designer drugs and related compounds to the urine drug tests Instant-View ? (IV) (the Methamphetamine (MA) test, the Amphetamine 300 test, and the MDMA test) have been investigated. An on-site urine test kit consisting of these three IV tests has been evaluated for the on-site screening of MA users, and the kit has been found to have satisfactory specificity for drug enforcement purposes by separately detecting both MA and its metabolite amphetamine. The cross-reactivity profiles of Emit(?) II Plus Amphetamines Assay, Emit(?) II Plus Ecstasy assay, and Emit(?) d.a.u.(?) Amphetamine Class assay have also been investigated and discussed.     

Evaluation of four oral fluid devices (DDS®, Drugtest 5000®, Drugwipe 5+® and RapidSTAT®) for on-site monitoring drugged driving in comparison with UHPLC-MS/MS analysis

New Italian legislation on driving under the influence of drugs considers oral fluid (OF) as a possible alternative drug testing matrix. On this basis, the present research was carried out to evaluate the applicability of four commercial on-site OF drug screening devices, namely DDS(?), Drugtest 5000(?), Drugwipe 5+(?) and RapidSTAT(?), in a real operative context. Preliminarily trained police officers tested randomly stopped drivers with two different kits side-by-side during roadside patrols. A central laboratory confirmed on-site kits' results by UHPLC-MS/MS analysis of the saliva specimen remaining after the screening analysis. 1025 drivers were submitted to the OF tests: 11.6% were positive for cocaine and metabolites, 11.1% for THC, 6% for amphetamines and amphetamine-type designer drugs and 2.3% for ketamine. The sensitivities of the kits were 81% (RapidSTAT(?)), 82% (DDS(?)), 90% (Drugwipe 5+(?)) and 97% (Drugtest 5000(?)) for cocaine and 38% (DDS(?)), 47% (Drugwipe 5+(?)), 72% (RapidSTAT(?)) and 92% (Drugtest 5000(?)) for THC. Drugtest 5000 was the only kit showing an acceptable sensitivity for on-site application. Only Drugtest 5000(?) and RapidSTAT(?) could be evaluated for amphetamines and methamphetamines: Drugtest 5000(?) showed a sensitivity of 100% in the case of amphetamines and 86% for methamphetamines, while RapidSTAT(?) 90% and 76% respectively. Nowadays, ketamine is not included in the target analytes of any on-site devices, but it was systematically included in the UHPLC-MS/MS confirmatory analysis. To ensure adequate reliability, MS confirmation of on-site OF screening tests is anyway always necessary, due to the presence of a significant number of false positive results even when using the commercial kit with the best performance.