Trace isotope analysis of Ricinus communis seed core for provenance determination by laser ablation-ICP-MS.

The castor bean plant, Ricinus communis, grows wild throughout many regions of Australia. The seeds of the plant contain the schedule 1 chemical agent ricin, a type II ribosomal inhibiting protein. Currently there are limited analytical techniques that can be applied in analysis of the seeds to establish attribution. In this study, laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) was used for the analysis of seeds collected from 68 plants across 38 locations around Australia. Of the 92 elemental isotopes measured, fifteen (24Mg, 27Al, 44Ca, 53Cr, 55Mn, 57Fe, 60Ni, 65Cu, 66Zn, 75As, 85Rb, 88Sr, 98Mo, 138Ba and 202Hg) yielded data that were relevant to all collection sites. Data were further analysed using multivariate statistical analysis which facilitated the potential for the identification of unique provenance isotopes. Furthermore, this analysis indicated that 59Co was present at significant levels in Victorian and Sydney specimens only.

Multi-element analysis using inductively coupled plasma mass spectrometry and inductively coupled plasma atomic emission spectroscopy for provenancing of animals at the continental scale.

Chemical signatures within the environment vary between regions as a result of climatological, geochemical and anthropogenic influences. These variations are incorporated into the region's geology, soils, water and vegetation; ultimately making their way through the food chain to higher level organisms. Because the variation in chemical signatures between areas is significant, a specific knowledge of differences in elemental distribution patterns between, and within populations, could prove beneficial for provenancing animals or animal related products when applied to indigenous and feral faunal populations. The domestic pig (Sus scrofa domestica) was used as an investigative model to determine the feasibility of using a chemical traceability method for the provenance determination of animal tissue. Samples of pig muscle, tongue, stomach, heart, liver and kidney were collected from known farming areas around Australia. Samples were digested in 1:3 H2O2:HNO3 and their elemental composition determined using solution based Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES) and Inductively Coupled Plasma Mass Spectrometry (ICP-MS). Pigs from different growing regions in Australia could be distinguished based on the chemical signature of each individual tissue type. Discrimination was possible at a region, state and population level. This investigation demonstrates the potential for multi-element analysis of low genetic variation native and feral species of forensic relevance.

Provenance establishment of coffee using solution ICP-MS and ICP-AES.

Statistical interpretation of the concentrations of 59 elements, determined using solution based inductively coupled plasma mass spectrometry (ICP-MS) and inductively coupled plasma emission spectroscopy (ICP-AES), was used to establish the provenance of coffee samples from 15 countries across five continents. Data confirmed that the harvest year, degree of ripeness and whether the coffees were green or roasted had little effect on the elemental composition of the coffees. The application of linear discriminant analysis and principal component analysis of the elemental concentrations permitted up to 96.9% correct classification of the coffee samples according to their continent of origin. When samples from each continent were considered separately, up to 100% correct classification of coffee samples into their countries, and plantations of origin was achieved. This research demonstrates the potential of using elemental composition, in combination with statistical classification methods, for accurate provenance establishment of coffee.

The development of analytical and interpretational protocols to facilitate the provenance establishment of polycarbonate headlamp lens material.

Despite the forensic significance of polycarbonate headlamp lenses, robust analytical protocols to facilitate their discrimination are scarce. In this study, laser ablation inductively coupled plasma mass spectrometry has been applied to the analysis of polycarbonate headlamp lenses with multivariate chemometrics techniques utilized to facilitate interpretation of the data. The analytical protocol involves the analysis of 46 analytes on material comprising the exterior surface of the lens. Using this data, it was found that although minor variation exists within a single headlamp lens, discrimination between lenses produced from a single manufacturing plant was still possible using iterative forward stepwise linear discriminant analysis processes. Discrimination between all headlamp lenses, with the exception of some lenses produced on the same day in a single plant, could be achieved using the analytical protocol. Furthermore, an interpretational protocol has been developed that has successfully classified all tested headlamp lens samples, within the discrimination limits of the analytical method.

A comparison of the use of refractive index (RI) and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) for the provenance establishment of glass bottles.

The use of laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) has been compared with the traditional method of refractive index (RI) measurement for the establishment of the provenance of glass bottles. Using the RI method alone, it is not possible to discriminate between certain glass bottles produced up to 18 days apart from a single manufacturing plant. Furthermore, variations in RI within a single bottle can be large enough to invalidate co-provenance establishment using this technique alone. Determination of the trace elemental composition of bottles collected over a 1-month period confirmed that minimal variation of trace metal distribution occurred within individual bottles made during this period. Therefore, the trace element composition of any fragment of glass from a broken bottle may be considered representative of the elemental composition of the entire bottle. In addition, statistical comparison of the distribution of approximately 38 of the 56 analytes that were determined established that it was possible to discriminate between two glass bottles manufactured in the same plant two hours apart. Using this methodology it has been possible to develop an analytical protocol to significantly improve the accurate comparison and provenance establishment of forensic glass evidence.

Trace element fingerprinting of Australian ocher using laser ablation inductively coupled plasma-mass spectrometry (LA-ICP-MS) for the provenance establishment and authentication of indigenous art.

The expansion of indigenous art and the interest it has generated both at a domestic and international level means large monetary transactions are taking place between art galleries or centers and purchasers. As such, an accurate and conclusive method for provenance determination of traditional indigenous artistic materials must be established that can, if necessary, be used to assist in authentication of artworks. Laser ablation inductively coupled plasma mass spectrometry was utilized for elemental differentiation and provenance establishment of ocher samples. This research was used to develop a robust scientific protocol which facilitates definitive and accurate determination of provenance of Australian ochers and the artworks created using them. Analysis of the results obtained through this study show that the trace metal distribution patterns alone appear to be sufficient evidence to establish provenance of specific ochers, although additional differentiation between ocher samples, using major element distribution patterns, was achieved through the utilization of X-ray analytical techniques.

Provenance determination of oriental porcelain using laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS).

The sale of fraudulent oriental ceramics constitutes a large proportion of the illegal artifact and antique trade and threatens to undermine the legitimate international market. The sophistication and skill of forgers has reached a level where, using traditional appraisal by eye and hand, even the most experienced specialist is often unable to distinguish between a genuine and fraudulent piece. In addition, current provenancing techniques such as energy-dispersive X-ray fluorescence (EDXRF) spectrometry and thermoluminescence (TL) dating can result in significant damage to the artifact itself. Laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS), a relatively nondestructive analytical technique, has been used for the provenance determination of materials based on geographical origin. The technique requires the production of a laser crater, c. 100 microm in diameter, which is essentially invisible to the naked eye. Debris from this crater is analyzed using ICP-MS, with the results forming the basis of the provenance establishment protocol. Chinese, Japanese, and English porcelain shards have been analyzed using this protocol and generic isotopic distribution patterns have been produced that enable the provenance establishment of porcelain artifacts to their country of production. Minor variations between elemental fingerprints of artifacts produced in the same country also indicate that it may be possible to further provenance oriental ceramics to a specific production region or kiln site.

Detecting art forgeries using LA-ICP-MS incorporating the in situ application of laser-based collection technology.

The nature of art lends itself to forgery as a skilled and determined forger can mimic the techniques and styles of an artist to a level where even an expert can be duped. The authentication of paintings is a subjective process, but modern techniques may provide the means to provenance artist pigments based on elemental composition. This study applies laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) to the analysis of artist paints from different manufacturers to identify variation between the elemental association patterns of these materials. The technique facilitates comparison of the paints used by an artist with produced works of art to assist provenancing initiatives of questioned materials. The effects of the trace element profiles of the backing substrate and binder on analytical data were also identified. By applying the technique to paint scraped from real paintings, a limited database was created to allow comparison to be made with some of Australian artist, Kathleen O'Connor's artworks and assist in determining production chronology. Data from this study were able to facilitate comparison of blue paints from two different paintings and confirm their co-provenance consequently determining the relative production date of a separate painting of previously unknown age. Preliminary trials of a prototype collection device designed to reduce damage and allow for in situ sampling of artworks were also undertaken. The device, which allows direct laser-based sampling of a complete painting, was tested using a Francis Ryan painting. The prototype allows for the collection of debris directly generated by LA-ICP-MS of a predefined area of a painting prior to subsequent analysis using direct LA-ICP-MS. This collection method significantly minimizes the amount of damage produced by conventional sampling methods. Analyses of the debris collected, using the prototype, were found to be comparable to the scrapings of equivalent paint analysed using direct LA-ICP-MS analysis.

The potential of using laser ablation inductively coupled plasma time of flight mass spectrometry (LA-ICP-TOF-MS) in the forensic analysis of micro debris.

The majority of crimes result in the generation of some form of physical evidence, which is available for collection by crime scene investigators or police. However, this debris is often limited in amount as modern criminals become more aware of its potential value to forensic scientists. The requirement to obtain robust evidence from increasingly smaller sized samples has required refinement and modification of old analytical techniques and the development of new ones. This paper describes a new method for the analysis of oxy-acetylene debris, left behind at a crime scene, and the establishment of its co-provenance with single particles of equivalent debris found on the clothing of persons of interest (POI). The ability to rapidly determine and match the elemental distribution patterns of debris collected from crime scenes to those recovered from persons of interest is essential in ensuring successful prosecution. Traditionally, relatively large amounts of sample (up to several milligrams) have been required to obtain a reliable elemental fingerprint of this type of material [R.J. Walting , B.F. Lynch, D. Herring, J. Anal. At. Spectrom. 12 (1997) 195]. However, this quantity of material is unlikely to be recovered from a POI. This paper describes the development and application of laser ablation inductively coupled plasma time of flight mass spectrometry (LA-ICP-TOF-MS), as an analytical protocol, which can be applied more appropriately to the analysis of micro-debris than conventional quadrupole based mass spectrometry. The resulting data, for debris as small as 70mum in diameter, was unambiguously matched between a single spherule recovered from a POI and a spherule recovered from the scene of crime, in an analytical procedure taking less than 5min.

Extraction of gunshot residues from the larvae of the forensically important blowfly Calliphora dubia (Macquart) (Diptera: Calliphoridae).

Whole body concentrations of lead (Pb), barium (Ba) and antimony (Sb) were determined in larvae of the blowfly Calliphora dubia (Macquart) (Diptera: Calliphoridae) removed from a piece of beef shot and contaminated with gunshot residue and compared with the concentrations detected within larvae feeding on a control piece of beef. Whole larvae were taken into solution and analysed using inductively coupled plasma-mass spectrometry (ICP-MS). Significantly higher concentrations of Pb, Ba and Sb were detected within the larvae feeding on the shot piece of beef compared with larvae that were feeding on the control piece of beef. Initial results indicate that the concentrations of Pb and Sb within the larvae decrease as the duration of feeding increases, whereas Ba concentrations appear to increase, suggesting a bioaccumulation of Ba within the larvae. The second part of this experiment investigated the depuration of Pb, Ba and Sb from the larvae following removal of the gunshot residue source. A significant reduction in Pb, Ba and Sb concentrations within the larvae was observed following the transfer of larvae from the shot piece of beef to the control piece of beef.