ORCID Profile
0000-0003-2027-2241
Current Organisations
University of Western Australia
,
Murdoch University
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Publisher: Elsevier BV
Date: 2012
DOI: 10.1016/J.ACA.2011.10.018
Abstract: Raman spectra of a representative range of β-ketophenethylamine (β-KP), the rapidly growing family of cathinone-related "legal high" recreational drugs, have been recorded. These spectra showed characteristic changes that were associated with the pattern of substitution on the aromatic rings, for ex le, the compounds carrying substituents at the 4- position could be distinguished from 3,4-methylenedioxy "ecstasy" derivatives. They also showed small but detectable changes with differences in substitution on the ethylamine substituent. These features allowed the β-KPs present in seized casework s les to be identified. The seized s les typically contained only small amounts of bulking agents, which meant that the band intensities of these components within averaged data were very small. In contrast, grid s ling normally gave at least some spectra which had a higher than average proportion of the bulking agent(s), which allowed them to also be identified. This study therefore demonstrates that Raman spectroscopy can be used both to provide a rapid, non-destructive technique for identification of this class of drugs in seized s les and to detect minor constituents, giving a composition profile which can be used for drugs intelligence work.
Publisher: Elsevier BV
Date: 07-2018
DOI: 10.1016/J.FORSCIINT.2018.03.049
Abstract: The Phadebas
Publisher: Wiley
Date: 28-08-2007
DOI: 10.1111/J.1556-4029.2007.00515.X
Abstract: 2,5,-Dimethoxy-4-bromo hetamine (DOB) is of particular interest among the various "ecstasy" variants because there is an unusually long delay between consumption and effect, which dramatically increases the danger of accidental overdose in users. Screening for DOB in tablets is problematic because it is pharmacologically active at 0.2-3 mg, which is c. 50 times less than 3,4-methylenedioxy-N-methyl hetamine (MDMA) and makes it more difficult to detect in seized tablets using conventional spot tests. The normal Raman spectra of seized DOB tablets are dominated by the bands of the excipient with no evidence of the drug component. Here we report the first use of on-tablet surface-enhanced Raman spectroscopy (SERS) to enhance the signal from a low concentration drug. Raman studies (785-nm excitation) were carried on series of model DOB/lactose tablets (total mass c. 400 mg) containing between 1 mg and 15 microg of DOB and on seized DOB tablets. To generate surface-enhanced spectra, 5 microL of centrifuged silver colloid was dispensed onto the upper surface of the tablets, followed by 5 microL of 1.0 mol/dm(3) NaCl. The probe laser was directed onto the treated area and spectra accumulated for c. 20 sec (10 sec x 2). It was found that the enhancement of the DOB component in the model tablets containing 1 mg DOB/tablet and in the seized tablets tested was so large that their spectra were completely dominated by the vibrational bands of DOB with little or no contribution from the unenhanced lactose excipient. Indeed, the most intense DOB band was visible even in tablets containing just 15 microg of the drug. On-tablet surface-enhanced Raman spectroscopy is a simple method to distinguish between low dose DOB tablets and those with no active constituent. The fact that unique spectra are obtained allows identification of the drug while the lack of s le preparation and short signal accumulation times mean that the entire test can be carried out in <1 min.
Publisher: Informa UK Limited
Date: 20-05-2019
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C5CC06745F
Abstract: A set of seized “legal high” s les and pure novel psychoactive substances have been examined by surface-enhanced Raman spectroscopy using polymer-stabilized Ag nanoparticle (Poly-SERS) films.
Publisher: Elsevier BV
Date: 07-1995
Publisher: Elsevier BV
Date: 03-2012
DOI: 10.1016/J.FORSCIINT.2011.08.002
Abstract: It has been shown that a handheld Raman spectrometer can be used to determine hydrogen peroxide concentration in aqueous solutions in seconds. To allow quantitative analysis, the aqueous peroxide s les were mixed 50/50 (v/v) with a 4mol/dm(3) sodium perchlorate solution which acted as the internal standard. Standard calibration using relative peak heights of the strongest perchlorate (932cm(-1)) and peroxide bands (876cm(-1)) gave an average error of 1.43% for s les in the range 5-30% peroxide. PLS regression of the same data set gave an average error of 0.98%. In addition, the concentrations of the s les were estimated by searching spectra against a library of standard spectra prepared using the same range of peroxide concentrations at 5% increments and with the same perchlorate internal standard. It was found that the library searching method classified all the test s les correctly, matching either the spectra of the same concentration, if they were present, or matching to the closest concentration if an exact match was not possible. This method thus provides a very rapid technique to allow determination of hydrogen peroxide concentrations in the field, for ex le at suspected improvised explosives manufacturing sites, without complex calibration procedures.
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C5AN02326B
Abstract: The potential of IR absorption and Raman spectroscopy for rapid identification of novel psychoactive substances (NPS) has been tested using a set of 221 unsorted seized s les suspected of containing NPS.
Publisher: Elsevier BV
Date: 10-2019
DOI: 10.1016/J.FORSCIINT.2019.109957
Abstract: We report the peptide content of decomposition fluid produced under field-based conditions and in the absence of a soil matrix. Sixteen domestic pig (Sus scrofa domesticus) cadavers were used to model human decomposition in trials conducted in the summer and winter months in Western Australia. Physical characteristics were recorded and the peptide components of decomposition fluid were analysed using high performance liquid chromatography-time of flight mass spectrometry. A range of peptides was consistently detected in both summer and winter. Thirty seven peptides were common to both trials 22 originating from haemoglobin subunit beta, 1 from haemoglobin subunit alpha, 4 from beta-enolase, and 2 from creatine kinase. In agreement with our previous findings, 13 peptides occurred consistently, regardless of trial conditions. Degradation patterns for haemoglobin subunits alpha and beta in summer and winter were similar when expressed in ADD and when adjusted for differences in temperature. The consistent identification of several protein-specific peptides generated during decomposition trials conducted under different temperature and rainfall regimes suggests that quantitative peptide analysis may be useful in estimating time since death.
Publisher: Wiley
Date: 15-03-2013
DOI: 10.1002/JRS.4202
Publisher: Wiley
Date: 13-07-2011
DOI: 10.1002/JRS.2982
Publisher: SAGE Publications
Date: 11-2005
DOI: 10.1366/000370205774783296
Abstract: The ability of Raman spectroscopy and Fourier transform infrared (FT-IR) microscopy to discriminate between resins used for the manufacture of architectural finishes was examined in a study of 39 s les taken from a commercial resin library. Both Raman and FT-IR were able to discriminate between different types of resin and both split the s les into several groups (six for FT-IR, six for Raman), each of which gave similar, but not identical, spectra. In addition, three resins gave unique Raman spectra (four in FT-IR). However, approximately half the library comprised s les that were sufficiently similar that they fell into a single large group, whether classified using FT-IR or Raman, although the remaining s les fell into much smaller groups. Further sub- ision of the FT-IR groups was not possible because the experimental uncertainty was of similar magnitude to the within-group variation. In contrast, Raman spectroscopy was able to further discriminate between resins that fell within the same groups because the differences in the relative band intensities of the resins, although small, were larger than the experimental uncertainty.
Publisher: Wiley
Date: 05-2004
DOI: 10.1002/JRS.1160
Publisher: SAGE Publications
Date: 11-2005
DOI: 10.1366/000370205774783232
Abstract: White household paints are commonly encountered as evidence in the forensic laboratory but they often cannot be readily distinguished by color alone so Fourier transform infrared (FT-IR) microscopy is used since it can sometimes discriminate between paints prepared with different organic resins. Here we report the first comparative study of FT-IR and Raman spectroscopy for forensic analysis of white paint. Both techniques allowed the 51 white paint s les in the study to be classified by inspection as either belonging to distinct groups or as unique s les. FT-IR gave five groups and four unique s les Raman gave seven groups and six unique s les. The basis for this discrimination was the type of resin and/or inorganic pigments/extenders present. Although this allowed approximately half of the white paints to be distinguished by inspection, the other half were all based on a similar resin and did not contain the distinctive modifiers igments and extenders that allowed the other s les to be identified. The experimental uncertainty in the relative band intensities measured using FT-IR was similar to the variation within this large group, so no further discrimination was possible. However, the variation in the Raman spectra was larger than the uncertainty, which allowed the large group to be ided into three subgroups and four distinct spectra, based on relative band intensities. The combination of increased discrimination and higher s le throughput means that the Raman method is superior to FT-IR for s les of this type.
Publisher: Royal Society of Chemistry (RSC)
Date: 2000
DOI: 10.1039/A908091K
Abstract: Raman spectroscopy with far-red excitation has been used to study seized, tableted s les of MDMA (N-methyl-3,4-methylenedioxy hetamine) and related compounds (MDA, MDEA, MBDB, 2C-B and hetamine sulfate), as well as pure standards of these drugs. We have found that by using far-red (785 nm) excitation the level of fluorescence background even in untreated seized s les is sufficiently low that there is little difficulty in obtaining good quality data with moderate 2 min data accumulation times. The spectra can be used to distinguish between even chemically-similar substances, such as the geometrical isomers MDEA and MBDB, and between different polymorphic/hydrated forms of the same drug. Moreover, these differences can be found even in directly recorded spectra of seized s les which have been bulked with other materials, giving a rapid and non-destructive method for drug identification. The spectra can be processed to give unambiguous identification of both drug and excipients (even when more than one compound has been used as the bulking agent) and the relative intensities of drug and excipient bands can be used for quantitative or at least semi-quantitative analysis. Finally, the simple nature of the measurements lends itself to automatic s le handling so that s le throughputs of 20 s les per hour can be achieved with no real difficulty.
Publisher: Informa UK Limited
Date: 18-03-2020
Publisher: Wiley
Date: 10-01-2012
Publisher: Wiley
Date: 27-01-2020
DOI: 10.1002/WIDM.1354
Abstract: A review was undertaken of the developments made with integrating forensic evidence into the analytical process to support police investigations. Evidence such as DNA, fingerprints, fibers, accelerants, tyre marks, and so forth, can support to differing degrees the various working theories or hypotheses about the nature of the alleged crime, the persons of interest and the modus operandi. Investigators however, either forensic or detective, bring various biases to evidence capture and analysis, biases which are better understood in the intelligence community. Structured analytical techniques have a long history in intelligence analysis, for ex le analysis of competing hypotheses, which serves several purposes: information sharing, clarity of communication, and to highlight the common forms of bias brought to bear in an investigation. We illustrate the representation of links based on traces and intelligence, and how these can be stored in databases permitting better “reasoning” with evidence. We also present some recommendations for integration of forensic intelligence into the investigative analytic process and review information systems in this area. This article is categorized under: Fundamental Concepts of Data and Knowledge Human Centricity and User Interaction Application Areas Society and Culture Fundamental Concepts of Data and Knowledge Knowledge Representation
Publisher: Elsevier BV
Date: 02-2020
DOI: 10.1016/J.FORSCIINT.2019.110117
Abstract: The ability to conduct accurate retrospective homicide comparative research is reliant on the publishing of robust studies that assess the specifics of homicides in a standardised manner. To address these matters at the Institute of Forensic Medicine (IFM) in Pristina, Kosovo, the IFM homicide data of the years 2006-2015 was retrospectively studied. In general, there was a year on year downward trend in the number of homicide deaths in Kosovo per 100,000 people, however it was noted that a standardisation method to record homicides in Kosovo has not been developed and as such, the data may not be complete. In addition, the analysis of the IFM data demonstrated that firearms were consistently used in 73.76 % of all homicides committed between 2006-2015 but the examination of, and the specific documentation of the types of firearms used was not recorded. This is important to provide evidence to enforce legislation to reduce the availability of these weapons and ultimately the number of homicides. Consequently, this study aimed to compare global homicide trends relative to the retrospective homicide data from Kosovo, to inform and address the need for prevention programmes and to establish standardised recording of homicides in Kosovo.
Publisher: Royal Society of Chemistry (RSC)
Date: 2003
DOI: 10.1039/B308312H
Abstract: Here we report the results of the largest study yet carried out on composition profiling of seized "ecstasy" tablets by Raman spectroscopy. Approximately 1500 tablets from different seizures in N. Ireland were analysed and even though practically all the tablets contained MDMA as active constituent, there were very significant differences in their Raman spectra, which were due to variations in both the nature and concentration of the excipients used and/or the degree of hydration of the MDMA. The ratios of the peak heights of the prominent drug bands at 810 cm(-1) and 716 cm(-1) (which vary with hydration state of the drug), and the drug band at 810 cm(-1) against the largest clearly discernible excipient band in the spectrum were measured for all the s les. It was found that there was sufficient variation in composition in the general s le population to make any matches between batches of tablets taken from different seizures significant, rather than the result of random chance. Despite the large number of different batches of tablets examined in this study, only two ex les of indistinguishable sets of tablets were found and in only one of these had the two batches of tablets been seized at different times. Finally, the fact that there are many ex les of batches of tablets (particularly in different batches taken from single seizures) in which the differences between each set are sufficiently small that they appear to arise only from random variations within a standard manufacturing method implies that, with more extensive data, it may be possible to recognize the "signature" of tablets prepared by major manufacturers.
Publisher: Elsevier BV
Date: 08-2018
DOI: 10.1016/J.FORSCIINT.2018.05.021
Abstract: In sexual assault cases and more specifically those involving childhood sexual abuse (CSA), victims may have had their potentially semen-stained clothing washed multiple times before a criminal investigation commences. Although it has been previously demonstrated that spermatozoa persist on cotton clothing following a single wash cycle, items of clothing washed multiple times are not routinely examined in these cases because of the assumption that the laundering process would have removed all seminal fluid and spermatozoa. The aim of this study was to examine the persistence of seminal fluid and spermatozoa on a range of fabric types including cotton, nylon, terry towel (100% cotton), polyester fleece, satin and lace which were laundered up to six times. Three techniques were used for the detection of seminal fluid and spermatozoa: an alternative light source, acid phosphatase test and microscopy. The study demonstrated that spermatozoa persisted on cotton and terry towel following six wash cycles. This data emphasises the need to recover and examine items of clothing and bedding of victims for semen, even if the item has been washed multiple times.
Publisher: SAGE Publications
Date: 2005
Abstract: The potential of Raman spectroscopy to discriminate between architectural finishes (household paint) has been investigated using a test set of 51 “lilac” paints and three different excitation wavelengths. The spectra obtained with visible excitation typically displayed a series of intense Raman bands on a featureless fluorescence background but the spectra of all the paints studied had essentially identical bands. With 785 nm excitation, although the same bands that dominated the 514 nm spectra were still observed, other bands with comparable intensity also appeared. The two strongest scattering constituents were identified as a dioxazine dye, Violet 23 and β-Cu(phthalocyanine). A scatter plot of the intensities of marker bands for these constituents (normalized to the strong rutile bands that were always present) showed that, despite the fact that the s le set spanned a wide range of rutile: dioxazine dye: phthalocyanine ratios, many of the s les had very similar ratios and could not be discriminated. However, all the s les (even those with similar relative proportions of the main constituents) could be discriminated on the basis of their minor constituents, either by manually measuring band intensities or through the creation and searching of spectral libraries.
Publisher: Elsevier BV
Date: 1996
Publisher: Elsevier BV
Date: 07-1994
Publisher: Royal Society of Chemistry (RSC)
Date: 2000
DOI: 10.1039/B005662F
Abstract: Raman spectroscopy with far-red excitation has been investigated as a simple and rapid technique for composition profiling of seized ecstasy (MDMA, N-methyl-3,4-methylenedioxy hetamine) tablets. The spectra obtained are rich in vibrational bands and allow the active drug and excipient used to bulk the tablets to be identified. Relative band heights can be used to determine drug/excipient ratios and the degree of hydration of the drug while the fact that 50 tablets per hour can be analysed allows large numbers of spectra to be recorded. The ability of Raman spectroscopy to distinguish between ecstasy tablets on the basis of their chemical composition is illustrated here by a s le set of 400 tablets taken from a large seizure of > 50,000 tablets that were found in eight large bags. The tablets are all similar in appearance and carry the same logo. Conventional analysis by GC-MS showed they contained MDMA. Initial Raman studies of s les from each of the eight bags showed that despite some tablet-to-tablet variation within each bag the contents could be classified on the basis of the excipients used. The tablets in five of the bags were sorbitol-based, two were cellulose-based and one bag contained tablets with a glucose excipient. More extensive analysis of 50 tablets from each of a representative series of s le bags have distribution profiles that showed the contents of each bag were approximately normally distributed about a mean value, rather than being mixtures of several discrete types. Two of the sorbitol-containing s le sets were indistinguishable while a third was similar but not identical to these, in that it contained the same excipient and MDMA with the same degree of hydration but had a slightly different MDMA/sorbitol ratio. The cellulose-based s les were badly manufactured and showed considerable tablet-to-tablet variation in their drug/excipient ratio while the glucose-based tablets had a tight distribution in their drug/excipient ratios. The degree of hydration in the MDMA feedstocks used to manufacture the cellulose-, glucose- and sorbitol-based tablets were all different from each other. This study, because it centres on a single seizure of physically similar tablets with the same active drug, highlights the fact that simple physical descriptions coupled with active drug content do not in themselves fully characterize the nature of the seized materials. There is considerable variation in the composition of the tablets within this single seizure and the fact that this variation can be detected from Raman spectra demonstrates that the potential benefits of obtaining highly detailed spectra can indeed translate into information that is not readily available from other methods but would be useful for tracing of drug distribution networks.
Publisher: Elsevier BV
Date: 07-1994
Publisher: Elsevier BV
Date: 06-2020
Publisher: Elsevier BV
Date: 07-1994
Publisher: Elsevier BV
Date: 05-2019
DOI: 10.1016/J.FORSCIINT.2019.02.048
Abstract: We report the preliminary observations of the peptide content of decomposition fluid produced under controlled laboratory conditions and in the absence of a soil matrix. Four domestic pig (Sus scrofa domesticus) cadavers were used to model human decomposition over a four-week trial period physical characteristics were recorded and the peptide components of decomposition fluid was analysed using high performance liquid chromatography-time of flight mass spectrometry. Preliminary data analysis indicated that a range of peptides were consistently detected across the course of the trial period and 27 of these were common to all four cadavers 22 originating from haemoglobin. The peptides associated with haemoglobin subunit alpha and beta displayed a breakdown pattern that remained consistent for all cadavers for the duration of the trial. Though identification of peptides during decomposition has potential for estimating the time since death, quantification of selected peptides is likely to be essential to identify time-dependent trends.
No related grants have been discovered for Samuel Speers.