Paul Kirkbride

Refining the estimation of illicit drug consumptions from wastewater analysis: Co-analysis of prescription pharmaceuticals and uncertainty assessment

Wastewater analysis is a promising monitoring tool to estimate illicit drug consumption at the community level. The advantage of this technique over traditional surveys and other surveillance methods has been emphasized in recent studies. However, there are methodological challenges that can affect reliability. The objectives of this study were to systematically reduce and assess uncertainties associated with sampling (through a stringent optimization of the sampling method) and the back calculation of per capita drug consumption (through a refined estimation of the number of people actively contributing to the wastewater in a given period). We applied continuous flow-proportional sampling to ensure the collection of representative raw wastewater samples. Residues of illicit drugs, opioids, prescription pharmaceuticals and one artificial sweetener were analyzed by liquid chromatography coupled with tandem mass spectrometry. A parameter estimating the number of people actively contributing to wastewater over a given period was calculated from the measured loads of prescription pharmaceuticals, their annual consumption and relative excretion data. For the calculation of substance loads in sewage, uncertainties were propagated considering five individual components: sampling, chemical analysis, flow measurements, excretion rates and the number of people contributing to the wastewater. The daily consumption per 1000 inhabitants was estimated to be almost 1000 mg for cannabis and several hundred mg for cocaine, methamphetamine and ecstasy. With the best sampling practice and current chemical analysis, we calculated the remaining uncertainty to be in the range of 20-30% (relative standard deviation, RSD) for the estimation of consumed drug masses in the catchment; RSDs for the per capita consumption were lower (14-24%), as one of the biggest uncertainty components (i.e. error in flow measurements) cancels out in the proposed method for the estimation of the number of people contributing to the daily wastewater volume. In this study, we provide methodological improvements that substantially enhance the reliability of the estimation method--a prerequisite for the application of this technique to meaningfully assess changes in drug consumption and the success of drug intervention strategies in future studies.

Forensic applications of desorption electrospray ionisation mass spectrometry (DESI-MS)

Desorption electrospray ionisation mass spectrometry (DESI-MS) is an emerging analytical technique that enables in situ mass spectrometric analysis of specimens under ambient conditions. It has been successfully applied to a large range of forensically relevant materials. This review assesses and highlights forensic applications of DESI-MS including the analysis and detection of illicit drugs, explosives, chemical warfare agents, inks and documents, fingermarks, gunshot residues and drugs of abuse in urine and plasma specimens. The minimal specimen preparation required for analysis and the sensitivity of detection achieved offer great advantages, especially in the field of forensic science.

Combined immunocapture and laser desorption/ionization mass spectrometry on porous silicon.

There is considerable interest in the highly parallelized mass spectrometry analysis of complex sample mixtures without any time-consuming prepurification. Porous silicon-based laser desorption/ionization mass spectrometry (pSi LDI-MS) is enabling technology for such analysis. Previous studies have focused on pSi surface functionalization to enhance sensitivity of detection and engineer surfaces for sample capture and enrichment in LDI-MS analysis. In this report, we build on this work by showing that surface functionalization of thin pSi films can be extended to the covalent immobilization of antibodies, producing a porous immunoaffinity surface. We demonstrate highly selective mass spectrometric detection of illicit drugs (benzodiazepines) on pSi films displaying antibenzodiazepine antibodies covalently immobilized via isocyanate chemistry. The effects of antibody immobilization conditions, antibody concentration, and surface blocking on LDI-MS performance and selectivity were studied. X-ray photoelectron spectroscopy (XPS) was instrumental in characterizing surface chemistry and optimizing LDI-MS performance. Overall, our approach is suitable for rapid and sensitive confirmatory analysis in forensic toxicology requiring only minimal sample volume and may be applied to other areas requiring small molecular analysis such as metabolomics and pharmacology.

Surface-assisted laser desorption ionization mass spectrometry techniques for application in forensics

Matrix-assisted laser desorption ionization (MALDI) mass spectrometry (MS) is an excellent analytical technique for the rapid and sensitive analysis of macromolecules (>700 Da), such as peptides, proteins, nucleic acids, and synthetic polymers. However, the detection of smaller organic molecules with masses below 700 Da using MALDI-MS is challenging due to the appearance of matrix adducts and matrix fragment peaks in the same spectral range. Recently, nanostructured substrates have been developed that facilitate matrix-free laser desorption ionization (LDI), contributing to an emerging analytical paradigm referred to as surface-assisted laser desorption ionization (SALDI) MS. Since SALDI enables the detection of small organic molecules, it is rapidly growing in popularity, including in the field of forensics. At the same time, SALDI also holds significant potential as a high throughput analytical tool in roadside, work place and athlete drug testing. In this review, we discuss recent advances in SALDI techniques such as desorption ionization on porous silicon (DIOS), nano-initiator mass spectrometry (NIMS) and nano assisted laser desorption ionization (NALDI™) and compare their strengths and weaknesses with particular focus on forensic applications. These include the detection of illicit drug molecules and their metabolites in biological matrices and small molecule detection from forensic samples including banknotes and fingerprints. Finally, the review highlights recent advances in mass spectrometry imaging (MSI) using SALDI techniques.

Screening of gunshot residues using desorption electrospray ionisation-mass spectrometry (DESI-MS)

Several studies have indicated that there are potential environmental sources of particles resembling inorganic primer found in gunshot residues (GSR); as a consequence examiners are reluctant to unambiguously assign the origin of inorganic particles. If organic gunshot residues (OGSR) were found in combination with inorganic particles, the possibility of environmental sources could be potentially eliminated, thereby significantly enhancing the strength of the evidence. Methods have been previously described whereby GSR specimens can be analysed for the presence of OGSR or inorganic GRS (IGSR). However, no methods have been reported that allow the analysis of both OGSR and IGSR on the same specimen. Described in this article is a direct method using desorption electrospray ionisation-mass spectrometry (DESI-MS) for the detection of methyl centralite (MC), ethyl centralite (EC) and diphenylamine (DPA) on adhesive tape GSR stubs typically used for scanning electron microscopy-energy-dispersive X-ray (SEM-EDX) analysis. The optimisation of numerous parameters was conducted using an experimental design. The results indicate that direct analysis of these organic components of GSR is possible although some limitations were also identified. This initial investigation has also indicated that subjecting stubs to DESI analysis does not interfere with subsequent SEM-EDX analysis of primer residues; therefore the technique described herein allows a comprehensive examination of GSR that would be highly probative in the event that both OGSR and IGSR are detected in the same specimen.

Forensic intelligence framework—Part I: Induction of a transversal model by comparing illicit drugs and false identity documents monitoring

Forensic intelligence is a distinct dimension of forensic science. Forensic intelligence processes have mostly been developed to address either a specific type of trace or a specific problem. Even though these empirical developments have led to successes, they are trace-specific in nature and contribute to the generation of silos which hamper the establishment of a more general and transversal model. Forensic intelligence has shown some important perspectives but more general developments are required to address persistent challenges. This will ensure the progress of the discipline as well as its widespread implementation in the future. This paper demonstrates that the description of forensic intelligence processes, their architectures, and the methods for building them can, at a certain level, be abstracted from the type of traces considered. A comparative analysis is made between two forensic intelligence approaches developed independently in Australia and in Europe regarding the monitoring of apparently very different kind of problems: illicit drugs and false identity documents. An inductive effort is pursued to identify similarities and to outline a general model. Besides breaking barriers between apparently separate fields of study in forensic science and intelligence, this transversal model would assist in defining forensic intelligence, its role and place in policing, and in identifying its contributions and limitations. The model will facilitate the paradigm shift from the current case-by-case reactive attitude towards a proactive approach by serving as a guideline for the use of forensic case data in an intelligence-led perspective. A follow-up article will specifically address issues related to comparison processes, decision points and organisational issues regarding forensic intelligence (part II).

An analysis of ethical issues in using wastewater analysis to monitor illicit drug use

AIMS To discuss ethical issues that may arise in using WWA to monitor illicit drug use in the general population and in entertainment precincts, prisons, schools and work-places. METHOD Review current applications of WWA and identify ethical and social issues that may be raised with current and projected future uses of this method. RESULTS Wastewater analysis (WWA) of drug residues is a promising method of monitoring illicit drug use that may overcome some limitations of other monitoring methods. When used for monitoring purposes in large populations, WWA does not raise major ethical concerns because individuals are not identified and the prospects of harming residents of catchment areas are remote. When WWA is used in smaller catchment areas (entertainment venues, prisons, schools or work-places) their results could, possibly, indirectly affect the occupants adversely. Researchers will need to take care in reporting their results to reduce media misreporting. Fears about possible use of WWA for mass individual surveillance by drug law enforcement officials are unlikely to be realized, but will need to be addressed because they may affect public support adversely for this type of research. CONCLUSIONS Using wastewater analysis to monitor illicit drug use in large populations does not raise major ethical concerns, but researchers need to minimize possible adverse consequences in studying smaller populations, such as workers, prisoners and students.

The use of forensic case data in intelligence-led policing: The example of drug profiling

To date, forensic science has predominantly focused on generating evidence for judicial proceedings. While many recognise its broader and important contribution to the initial stages of the forensic process, resources do not seem to be employed efficiently. It is often discovered retrospectively that necessary information was previously available in a database or within existing files. Such information could have been proactively used in order to solve a particular case, a number of linked cases or better understand the criminal activity as a whole. This article reviews this broader contribution of forensic science, with a particular emphasis on drug intelligence at the Australian Federal Police (AFP) in Australia. Using the AFP as a model organisation, an overview of the current situation and the contribution of physical and chemical profiling are first discussed. The situation in Europe, and in particular in Switzerland, is also presented. It is argued that a change of attitude towards a more intelligence-led perspective is required in forensic science in general, and in drug profiling in particular.

Time-of-flight secondary ion mass spectrometry analysis of hair from archaeological remains

Hair from four individuals excavated from burial sites in Pacatnamu, Peru from the Moche (450–800 AD) and Lambayeque (900–1100 AD) periods was sectioned longitudinally and analysed with time-of-flight secondary ion mass spectrometry (ToF-SIMS). An attempt was made to distinguish biogenic and diagenetic contributions to the elemental concentrations in the hair samples. Significant contamination was observed to have penetrated the hair samples from the burial environment. Results from the analyses indicate that the burial environment plays an important role in the postmortem variation in elemental content of hair samples. Various elements demonstrated an ability to permeate through the hair matrix over time. In addition, NaCl and what are believed to be aluminosilicates and mineral sulphates, were observed to have accumulated on the surface of the samples. Degradation of the samples was also suspected due to the presence of molecular fragments, possibly resulting from oxidation of the keratin proteins. The results should assist in the identification of reliable elemental signals in the analysis of ancient hair samples and promote caution when considering elements that are abundant in the burial environment.

Forensic analysis of condom and personal lubricants by capillary electrophoresis

Condoms may offer sexual assailants a simple and relatively effective means by which they may remove and dispose of the biological evidence of their contact with the victim. Without this valuable probative evidence, the investigator may need to turn to such alternative forms of physical evidence, such as the residue remaining from the condom lubricant, and any other additional lubricating substances, which may have been used by the assailant. In this study, 68 different condom and personal lubricant samples were analysed using micellar electrokinetic capillary chromatography (MEKC) with ultraviolet absorbance detection. The electropherograms were processed by principal component analysis (PCA) and classified with linear discriminant analysis. This classified 233 samples out of 263 into their correct sample group. An alternative method of classification in which the sample electropherograms were converted to vectors and a correlation was determined by the cosine of the angles between these vectors. This correctly classified 172 samples of the 296. Results indicate that the combination of CE with chemometric data treatment offers the potential of being a rapid and efficient means by which condom and personal lubricant samples may be differentiated. Although this analytical method at present lacks the sensitivity required for sexual assault swab analysis, it is hoped that future developments in instrumentation detection capabilities will permit its use one day as a routine casework tool.