Monitoraggio ambientale e biologico per la determinazione dell'esposizione occupazionale a diisocianati

The research project focused on the development and validation of an analytical method for the combined determination of the concentration in ambient air of 3 of the most used diisocyanates in the workplace: 1,6-hexamethylene diisocyanate (1,6-HDI) , 4,4'-diphenylmethane diisocyanate (4,4'-MDI) and 2,6-toluen diisocyanate (2,6-TDI). The analytical method was developed based on procedures indicated by the Occupational Safety and Health Administration (OSHA, ID OSHA 42 and ID OSHA 47) using high performance liquid chromatography coupled with a fluorimetric detector. The method has been validated and has been shown to have adequate sensitivity and precision for the analysis of real samples, in the context of environmental monitoring for the determination of the airborne concentrations of these substances. The method was then applied in determining the environmental concentration levels of 1.6-HDI, 4,4'-MDI and 2,6-TDI, as part of two monitoring campaigns, in two different work contexts. A further aim of the research project was the development and validation of analytical methods for the determination of urinary concentrations of 1,6-HDI, 4,4'-MDI and the two TDI isomers, 2, 4- and 2,6-TDI, or the corresponding diamines. For this purpose, gas chromatography coupled to the mass spectrometer detector was used as a separation and analytical identification technique. The method was identified starting from a comparison of the scientific literature on the subject and the indications provided by one of the most important sector agencies, the American Conference of Governmental Industrial Hygienists (ACGIH). The optimal analytical conditions were identified by conducting a series of tests, first in organic solvent and then in the urinary matrix of subjects not professionally exposed to diisocyanates or solvents. The urinary test matrix was treated by high temperature acid hydrolysis, as indicated by the majority of the work reported in the literature and in accordance with the indications in the ACGIH Documentation for the analysis of urinary samples of workers exposed to TDI and HDI. The 3 methods developed have been validated and have returned a sensitivity and precision appropriate to the determination of the concentration levels of the diamines of diisocyanates covered by the present research project. To date, it has been possible to apply these methods for the evaluation of the recorded internal dose for samples of patients exposed to bronchial provocation tests specific for the diagnosis of occupational asthma

Monitoraggio ambientale e biologico per la determinazione dell'esposizione occupazionale a diisocianati

The research project focused on the development and validation of an analytical method for the combined determination of the concentration in ambient air of 3 of the most used diisocyanates in the workplace: 1,6-hexamethylene diisocyanate (1,6-HDI) , 4,4'-diphenylmethane diisocyanate (4,4'-MDI) and 2,6-toluen diisocyanate (2,6-TDI). The analytical method was developed based on procedures indicated by the Occupational Safety and Health Administration (OSHA, ID OSHA 42 and ID OSHA 47) using high performance liquid chromatography coupled with a fluorimetric detector. The method has been validated and has been shown to have adequate sensitivity and precision for the analysis of real samples, in the context of environmental monitoring for the determination of the airborne concentrations of these substances. The method was then applied in determining the environmental concentration levels of 1.6-HDI, 4,4'-MDI and 2,6-TDI, as part of two monitoring campaigns, in two different work contexts. A further aim of the research project was the development and validation of analytical methods for the determination of urinary concentrations of 1,6-HDI, 4,4'-MDI and the two TDI isomers, 2, 4- and 2,6-TDI, or the corresponding diamines. For this purpose, gas chromatography coupled to the mass spectrometer detector was used as a separation and analytical identification technique. The method was identified starting from a comparison of the scientific literature on the subject and the indications provided by one of the most important sector agencies, the American Conference of Governmental Industrial Hygienists (ACGIH). The optimal analytical conditions were identified by conducting a series of tests, first in organic solvent and then in the urinary matrix of subjects not professionally exposed to diisocyanates or solvents. The urinary test matrix was treated by high temperature acid hydrolysis, as indicated by the majority of the work reported in the literature and in accordance with the indications in the ACGIH Documentation for the analysis of urinary samples of workers exposed to TDI and HDI. The 3 methods developed have been validated and have returned a sensitivity and precision appropriate to the determination of the concentration levels of the diamines of diisocyanates covered by the present research project. To date, it has been possible to apply these methods for the evaluation of the recorded internal dose for samples of patients exposed to bronchial provocation tests specific for the diagnosis of occupational asthma.Il progetto di ricerca si è incentrato sulla messa a punto e sulla validazione di una metodica analitica per la determinazione combinata della concentrazione in aria ambiente di 3 dei diisocianati maggiormente utilizzati in ambito lavorativo: 1,6-esametilen diisocianato (1,6-HDI), 4,4’-difenilmetano diisocianato (4,4’-MDI) e 2,6-toluen diisocianato (2,6-TDI). Il metodo analitico è stato sviluppato a partire da procedure indicate dall’Occupational Safety and Health Administration (OSHA; ID OSHA 42 e ID OSHA 47) utilizzando la cromatografia liquida ad alte prestazioni accoppiata a un rivelatore fluorimetrico. Il metodo è stato validato e ha dimostrato di avere sensibilità e precisione adeguate per l’analisi di campioni reali, nell’ambito di monitoraggi ambientali per la determinazione delle concentrazioni aerodisperse di tali sostanze. Il metodo è stato quindi applicato nella determinazione dei livelli di concentrazione ambientale di 1,6-HDI, 4,4’-MDI e 2,6-TDI, nell’ambito di due campagne di monitoraggio, in due diversi contesti lavorativi. Ulteriore scopo del progetto di ricerca è stata la messa a punto e la validazione di metodiche analitiche per la determinazione delle concentrazioni urinarie dei metaboliti dell’1,6-HDI, del 4,4’-MDI e dei due isomeri del TDI, 2,4- e 2,6-TDI, ovvero le corrispondenti diammine. A tal fine è stata utilizzata come tecnica di separazione ed identificazione analitica la gascromatografia accoppiata al rivelatore spettrometro di massa. La metodica è stata individuata a partire da una comparazione della letteratura scientifica sull’argomento e dalle indicazioni fornite da una delle agenzie di settore di maggiore rilievo, l’American Conference of Governmental Industrial Hygienists (ACGIH). Le condizioni analitiche ottimali sono state individuate conducendo una serie di prove, prima in solvente organico quindi in matrice urinaria di soggetti non esposti professionalmente a diisocianati o a solventi. La matrice urinaria delle prove è stata trattata mediante idrolisi acida ad alta temperatura, come indicato dalla maggioranza dei lavori riportati in letteratura ed in accordo con quanto indicato nella Documentation ACGIH per l’analisi dei campioni urinari dei lavoratori esposti a TDI e a HDI. I 3 metodi messi a punto sono stati validati ed hanno restituito una sensibilità ed una precisione adeguate alla determinazione dei livelli di concentrazione delle diammine dei diisocianati oggetto del presente progetto di ricerca. Ad oggi è stato possibile applicare tali metodiche per la valutazione della dose interna registrata per campioni di pazienti esposti a test di provocazione bronchiale specifici per la diagnosi di asma professionale

From Thioxo Cluster to Dithio Cluster: Exploring the Chemistry of Polynuclear Zirconium Complexes with S,O and S,S Ligands

Three different zirconium thio and oxothio clusters, characterized by different coordination modes of dithioacetate and/or monothioacetate ligands, were obtained by the reaction of monothioacetic acid with zirconium n-butoxide, Zr(O(n)Bu)(4), in different experimental conditions. In particular, we isolated the three polynuclear Zr(3)(μ(3)-SSSCCH(3))(2)(SSCCH(3))(6)·2(n)BuOH (Zr(3)), Zr(4)(μ(3)-O)(2)(μ-η(1)-SOCCH(3))(2)(SOCCH(3))(8)(O(n)Bu)(2) (Zr(4)), and Zr(6)(μ(3)-O)(5)(μ-SOCCH(3))(2)(μ-OOCCH(3))(SOCCH(3))(11)((n)BuOH) (Zr(6)) derivatives, presenting some peculiar characteristics. Zr(6) has an unusual star-shaped structure. Only sulfur-based ligands, viz., chelating dithioacetate monoanions and an unusual ethane-1,1,1-trithiolate group μ(3) coordinating the Zr ions, were observed in the case of Zr(3). 1D and 2D NMR analyses confirmed the presence of differently coordinated ligands. Raman spectroscopy was further used to characterize the new polynuclear complexes. Time-resolved extended X-ray absorption fine structure measurements, devoted to unraveling the cluster formation mechanisms, evidenced a fast coordination of sulfur ligands and subsequent relatively rapid rearrangements

Effect of Benzene Exposure on the Urinary Biomarkers of Nucleic Acid Oxidation in Two Cohorts of Gasoline Pump Attendants

(1) Background: The oxidized guanine derivatives excreted into urine, products of DNA and RNA oxidation and repair, are used as biomarkers of oxidative damage in humans. This study aims to evaluate oxidative damage in gasoline pump attendants occupationally exposed to benzene. Benzene is contained in the gasoline but it is also produced from traffic and from smoking. (2) Methods: Twenty-nine gasoline pump attendants from two major cities of Saudi Arabia and 102 from Italy were studied for urinary 8-oxo-7,8-dihydroguanine (8-oxoGua), 8-oxo-7,8-dihydro-2′-deoxyguanosine (8-oxodGuo), 8-oxo-7,8-dihydroguanosine (8-oxoGuo), and S-phenyl-mercapturic acid (SPMA) for benzene exposure and urinary cotinine for smoking status assessment by liquid chromatography-tandem mass spectrometry. Airborne benzene was also assessed in the Italian group by gas-chromatography with flame ionization detector (GC-FID). (3) Results: The results suggest that high levels of benzene exposure can cause an accumulation of SPMA and bring about the formation of the oxidation biomarkers studied to saturation. At low exposure levels, SPMA and oxidation biomarker levels were correlated among them and were associated with the smoking habit. (4) Conclusions: The study confirms the association between benzene exposure and the excretion of nucleic acid oxidation biomarkers and enhances the importance of measuring the smoking habit, as it can significantly influence oxidative damage, especially when the exposure levels are low