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  • Author: Irena Karačonji x
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Comparison Between Dynamic Headspace and Headspace Solid-Phase Microextraction for Gas Chromatography of Btex in Urine

The aim of this study was to compare two extraction procedures: dynamic headspace-purge and trap (PT) and headspace solid-phase microextraction (HS-SPME) for gas chromatographic determination of benzene, toluene, ethylbenzene, and isomeric xylenes (BTEX) in urine with photoionization (PID) and mass spectrometric (MS) detection, respectively. Both methods showed linearity in the range of interest [(50-2000) ng L-1], good accuracy (80% to 100 %), and repeatability (RSD≤11 %). Detection limits were in the low ng L-1 level for both methods, although slightly greater sensitivity was found for the PT method. In comparison with PT, HS-SPME was simpler and required less time for analysis.

Although the analytical features of both examined methods are appropriate for biomonitoring of environmental exposure to BTEX, only the HS-SPME-GC-MS method is recommended for routine analysis of BTEX in urine. The method was applied for the quantitative analysis of BTEX in urine samples collected from non-smokers (n=10) and smokers (n=10).

Determination of mite Allergens in House Dust Using the Enzyme Immunoassay

The aim of this study was to determine the level of two major mite allergens Dermatophagoides pteronyssinus (Der p 1) and Dermatophagoides farinae (Der f 1) in 30 urban homes in Zagreb, Croatia, using the enzyme immunoassay with two monoclonal antibodies which has been established as the reference method for indoor allergen analysis. Dust samples were taken by vacuuming a carpeted area and collected on cellulose filters. The ranges of Der p 1 and Der f 1 were (0.1-12.5) μg g-1 (median 0.32 μg g-1) and (0.1-31.2) μg g-1 (median 0.35 μg g-1), respectively. Der p 1 and Der f 1 (>2 μg g-1) associated with increased risk of sensitization to mite allergens were found in approximately 16% homes for each allergen. The sum of allergen (Der p 1 + Der f 1) exceeded the lower threshold in 27% of homes. Analytical evaluation of the ELISA assay showed satisfactory results for precision (intra-assay CV <6.9%, inter-assay CV<13.3%), accuracy (91% to 93%), and sensitivity (2 ng mL-1).

The ELISA assay for the measurement of dust mite allergens demonstrated very good analytical characteristics for routine laboratory use, and will provide the essential basis for our future studies of various indoor allergens.

Abstract

Hair analysis is a reliable tool for detecting long-term exposure to illegal drugs, including amphetaminetype stimulants, over periods from a few weeks to a few months, depending on the length of the hair used for analysis. Between 2000 and 2012, over 600 hair samples were analysed at the Institute for Medical Research and Occupational Health, Croatia (IMROH) for the presence of amphetamine-type stimulants. IMROH has used the same procedure for testing hair samples for amphetamine-type stimulants for over twelve years. It was found to be reliable for confirming repeated abuse of amphetamine-type stimulants. Gas chromatography/mass spectrometry (GC/MS) was used to determine amphetamine, methamphetamine, 3,4-methylenedioxyamphetamine (MDA), 3,4-methylenedioxymethamphetamine (MDMA-Ecstasy), and 3,4-methylenedioxyethylamphetamine (MDEA) in hair. Hair samples were either taken at the Institute, delivered by mail or a third person brought them to the laboratory. In most cases, the hair samples were tested anonymously. A total of 23 % of the tested samples were positive for one or more amphetamine-type stimulant. MDMA was the most frequently detected substance, whereas the most frequent combination was amphetamine with MDMA. Our results could indicate a trend in amphetamine-type stimulant abuse among young people in the Republic of Croatia.

Abstract

Imidacloprid, a neonicotinoid insecticide, has been used worldwide due to its selective toxicity for insects. Its residues may enter the food chain, which is why it is important to investigate the potential adverse effects of imidacloprid exposure. This review summarises current knowledge of the reproductive toxicity and disruptive endocrine effects of imidacloprid in laboratory animals. Investigations, conducted mostly on laboratory rats, have shown adverse effects of imidacloprid on the reproductive ability in both parental and offspring generation as well as on the development of the offspring. Like many pesticides, imidacloprid may also act as endocrine disrupting chemical (EDC). It may disrupt the metabolic homeostasis, contribute to obesity, and disrupt steroidogenesis by inhibiting cytochrome P450 (CYP) enzyme activities. All these adverse effects of imidacloprid may pose a serious risk for reproduction and development with long-term consequences in adulthood.

Abstract

Polychlorinated biphenyls (PCBs) are persistent pollutants, harmful to human health, which enter the human body mainly through food and bind to body fat. For these reasons their use in most countries is prohibited. Human milk has an advantage over other types of human samples in measuring human exposure to PCBs, as it is obtained with non-invasive sampling methods. In Europe, including Croatia, PCB levels have been monitored for many years. This review summarises PCB trends in human milk across Europe. The trend is generally downward, with higher levels prevailing in urban areas near industrial plants. The highest PCB levels were reported in the Czech Republic and Slovakia.

Abstract

Terrorist attacks on critical infrastructures can cause problems to a national stability and functioning. Food and water supply chains are some of the most important infrastructures, and it is the country’s (government’s) obligation to provide sufficient quantities of food and water to its population. Intentional food contamination can, among other motives, originate from an act of terrorism (with political or ideological motives) with the aim of causing fear (terror) among people. Food defence systems can help assess vulnerabilities, determine mitigation strategies for terrorist attack, estimate risks, and prevent a terrorist attack. Risk assessment and prevention also include control over the production and distribution of potential chemical, biological, radiological or nuclear (CBRN) agents or their related materials. When a terrorist attack occurs, rapid and organised response is essential in terms of determining the type of agent used, managing the diseased, ensuring the functioning of the food and water supply, and the recovery of the infrastructure system under attack. Food defence planning as part of a food counterterrorism strategy should include considerations regarding the global food market and the fact that ingredients are supplied from all over the world (vendor certificates). Preventing terrorist attacks on sources of food and water is a far better option than crisis management once an attack had already been committed, but governments should have a response to any scenario.

Abstract

The phenolic glycoside arbutin and its metabolite with uroantiseptic activity hydroquinone occur naturally in the leaves of various medicinal plants and spices. In this study, an extraction procedure coupled with gas chromatography-mass spectrometry (GC-MS) was developed to determine arbutin and hydroquinone content in strawberry tree (Arbutus unedo L., Ericaceae) leaves. The method showed good linearity (R2>0.9987) in the tested concentration range (0.5-200 μg mL-1), as well as good precision (RSD<5 %), analytical recovery (96.2-98.0 %), and sensitivity (limit of detection=0.009 and 0.004 μg mL-1 for arbutin and hydroquinone, respectively). The results obtained by the validated GC-MS method corresponded well to those obtained by high performance liquid chromatography (HPLC) method. The proposed method was then applied for determining arbutin and hydroquinone content in methanolic leaf extracts. The amount of arbutin in the leaves collected on the island of Koločep (6.82 mg g-1 dry weight) was found to be higher (tpaired=43.57, tc=2.92) in comparison to the amount of arbutin in the leaves collected on the island of Mali Lošinj (2.75 mg g-1 dry weight). Hydroquinone was not detected in any of the samples. The analytical features of the proposed GC-MS method demonstrated that arbutin and hydroquinone could be determined alternatively by gas chromatography. Due to its wide concentration range, the method could also be suitable for arbutin and hydroquinone analysis in leaves of other plant families (Rosaceae, Lamiaceae, etc.).

Abstract

Phthalates are esters of phthalic acid and aliphatic alcohol added to plastic to improve its softness, flexibility, and extensibility. They easily migrate from plastic products into the environment because of their physical and chemical properties. This review summarises their characteristics, distribution in the environment, monitoring, use, toxic effects on human health, regulatory limits in different matrices and products, and tolerable daily intake. The studies we have reviewed suggest that phthalates have a potential to affect reproduction and development in humans. Due to the inconsistent data, further studies are needed and, in the meantime, precautionary policies must be implemented. Here we draw attention to the methods of determining phthalate levels in alcoholic beverages and reported levels in plum spirits produced in Croatia. Legally produced and moderately consumed plum spirits do not seem to increase the risk of phthalate toxicity for human health. We conclude with recommendations for the effective monitoring of phthalate exposure in humans and for the implementation of alternative materials in alcohol production.

Abstract

This study investigated the mechanisms of hydroquinone toxicity and assessed the relationships between its cytotoxic, genotoxic, and cytogenetic effects tested at 8, 140, and 280 μg mL-1 in human peripheral blood lymphocytes exposed for 24 h. The outcomes of the treatments were evaluated using the apoptosis/necrosis assay, the alkaline comet assay, and the cytokinesis-block micronucleus (CBMN) cytome assay. The tested hydroquinone concentrations produced relatively weak cytotoxicity in resting lymphocytes, which mostly died via apoptosis. Hydroquinone’s marked genotoxic effects were detected using the alkaline comet assay. Significantly decreased values of all comet parameters compared to controls indicated specific mechanisms of hydroquinone-DNA interactions. Our results suggest that the two higher hydroquinone concentrations possibly led to cross-linking and adduct formation. Increased levels of DNA breakage measured following exposure to the lowest concentration suggested mechanisms related to oxidative stress and inhibition of topoisomerase II. At 8 μg mL-1, hydroquinone did not significantly affect MN formation. At 140 and 280 μg mL-1, it completely blocked lymphocyte division. The two latter concentrations also led to erythrocyte stabilization and prevented their lysis. At least two facts contribute to this study’s relevance: (I) this is the first study that quantifies the degree of reduction in total comet area measured in lymphocyte DNA after hydroquinone treatment, (II) it is also the first one on a lymphocyte model that adopted the “cytome” protocol in an MN assay and found that lymphocytes exposure even to low hydroquinone concentration resulted in a significant increase of nuclear bud frequency. Considering the limitations of the lymphocyte model, which does not possess intrinsic metabolic activation, in order to unequivocally prove the obtained results further studies using other appropriate cell lines are advised.

Abstract

In order to evaluate the effect of irinotecan (IRI) on urinary elimination of delta-9-tetrahydrocannabinol (THC) in a rat experimental model, we developed an analytical method for the determination of the mass concentration of THC and its metabolites [11-hydroxy-delta-9-tetrahydrocannabinol (THC-OH) and 11-nor-9-carboxy-delta-9-tetrahydrocannabinol (THC-COOH)] in the urine of rats treated only with THC and treated simultaneously with THC and irinotecan. For this purpose, hydrolysis and solid phase extraction conditions of the investigated analytes were optimised and a gas chromatography-mass spectrometry (GC-MS) method was developed to determine all three analytes in rat urine. The most effective hydrolysis method for THC, THC-OH, and THC-COOH conjugates was so-called tandem hydrolysis by the β-glucuronidase enzyme from Escherichia coli at 50 °C for 2 hours and followed by alkaline hydrolysis. The proposed method was then applied for determining concentrations of analytes in 24-hour rat urine. THC was not detected in either sample, THC-OH was detected in 50 % of samples, and THC-COOH in all of the samples. Enhanced urinary THC-COOH excretion was noted in rats administered combined treatment compared to single THC treatment. The method described herein was suitable for determining the mass concentration of THC metabolites in the rat urine due to its sensitivity (detection limits: 0.8-1.0 μg/L), accuracy (>96 %), and precision (RSD <6 %).