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Detection of fingermarks at a crime scene or on related items is of prime interest for forensic investigators, mainly for identification purposes. Most of the fingermarks are invisible to the naked eye, however. The application of detection techniques is required to establish visual contrast between the secretion residue and the underlying substrate. We give here a review of the field related to the concept of using stains to detect fingermarks. A distinction has been made between the physically driven classical detection techniques, the chemically driven ones, and those based on nanostructured materials, an emerging field in forensic science. [ABSTRACT FROM AUTHOR]

Smoking and/or grilling, when carried out with traditional methods involving direct contact with wood combustion fumes, is responsible for high contamination levels with carcinogenic polycyclic aromatic hydrocarbons (PAHs). The aim of this work was to investigate the PAH content of different smoked or grilled meat and fish products commonly consumed in Nigeria. A rapid method involving microwave-assisted saponification and simultaneous extraction followed by solid-phase extraction (SPE), high-performance liquid chromatography (HPLC) separation and spectrofluorometric detection was employed. Samples that were smoked or grilled using traditional systems, which use a wood fire, were heavily contaminated with benzo[a]pyrene (BaP) at levels ranging from 2.4 to 31.2 µg kg-1 wet weight. Considerably lower contamination levels were found in samples smoked or grilled in the laboratory using a charcoal fire (BaP from 0.7 to 2.8 µg kg-1 wet weight). The health risk associated with a daily consumption of 100 g of these products was also evaluated using the margin of exposure (MOE) approach. MOE values lower than 10,000 were obtained for all smoked/grilled commercial samples, indicating a potential concern for consumer health. [ABSTRACT FROM AUTHOR]

Abstract: A rapid extraction method involving microwave assisted extraction (MAE), followed by sample clean-up on a silica cartridge, reversed-phase high performance liquid chromatography (RP-HPLC) and spectrofluorimetric detection, was optimised for polycyclic aromatic hydrocarbon (PAH) determination in smoked meat. Compared to solvent extraction assisted by sonication, MAE, carried out with n-hexane on 2g of lyophilised sample at 115°C for 15min, allowed to obtain better extraction efficiencies. Limits of quantification (LOQ, s/n=10) lower than 0.2μg/kg wet weight were found for all PAHs, except for Fl (0.3μg/kg), P (0.6μg/kg) and IP (0.4μg/kg). The optimised procedure, that presented good analytical performances (with recoveries ranging from 77% to 103%, and precision within 10% for most of the PAHs), was applied to determine PAH content in different smoked meat products from the Italian market. [Copyright &y& Elsevier]

An on-line LC–GC method was used to assess the n-alkane composition of 40 olive oil samples obtained from three different cultivars from a restricted grove zone in Croatia. Olive samples were handpicked at three different ripening stages during four consecutive years. No significant differences were found in relation to the variable “period of harvesting”, while the effects “variety” and “year” as well as their interaction caused significant differences for most of the n-alkane components (p⩽0.05). Despite the influence of the production year, linear discriminant analysis based on the n-alkane components was able to correctly identify the variety of 97.5% of the samples. [Copyright &y& Elsevier]

Different classes of olive oils and other olive samples (olives, olive paste and olive pomace) collected during their production were analysed for mineral paraffins in the range of C[sub 15]-C[sub 45]. None of the 22 extra virgin olive oils contained mineral paraffins above the detection limit of 1 mg kg[sup -1]. Also, lampante virgin olive oil from the olive mill showed no detectable amounts, but olive oil from the market contained 6-30 mg kg[sup -1]. This contamination cannot be attributed to the refining step, which, on the contrary, partially removes the more volatile hydrocarbons, but could result from transport. Olive-pomace oils obtained by second centrifugation contained 16-145 mg kg[sup -1] mineral paraffins, presumably because of contamination during storage of the pomace. All olive-pomace oils from solvent extraction contained more than 100 mg kg[sup -1] mineral paraffins, also mainly from storage. Deposition of particulate matter from the air, vehicle exhaust emissions and direct contamination from the bulldozers used to move the pomace were identified as potential sources. [ABSTRACT FROM AUTHOR]

The evaluation of the content of waxes is request both by IOC Trade Standard and by Regulation (EEC) 2568/91 and its further amendments. The official method uses 15 g of silicic acid and elutes several fractions by using huge volumes of dangerous solvent (n-hexane). The developed method uses 1 g of silicic acid with a different particle size and less than 20 mL of solvent mixture, substituting n-hexane with less toxic isooctane. Briefly, after spiking with a suitable internal standard, oil sample is fractionated by SPE (Solid Phase Extraction) cartridge with 1 g of silica, waxes are eluted with 14 mL of isooctane/ethyl ether 99/1 (6 mL discarded and 8 mL collected), then, after elution sample is reconstitute in 200 μL of n-heptane and analysed by capillary GC. Data of “In home” validation, (repeatability, accuracy and recovery) and relative chromatograms are reported in this paper.

Abstract: Cheeses are among those high-protein-containing foodstuffs in which enzymatic and microbial activities cause the formation of biogenic amines from amino acids decarboxylation. Most of the methods for amine determination in this products involve acid extraction followed by a liquid–liquid purification step to selectively separate amines and amino acids. In this work a simple direct derivatization of the acidic extract with dansyl chloride (DCl) was applied. After an extraction step with diethyl ether, the amines were separated on a Kromasil C18 column using a water–acetonitrile elution gradient. Taking into consideration the recovery and repeatability data we can conclude that, when free amino acid determination is not of concern, the direct DCl derivatization procedure can be applied also for cheese samples with high free amino acid contents. [Copyright &y& Elsevier]