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Papers by Alin Constantin

Research paper thumbnail of Organochlorine contaminants in hair of adolescents from Iassy, Romania

Chemosphere, 2008

Human hair samples (n=42) from Iassy county (Eastern Romania) collected in 2002-2003 from adolesc... more Human hair samples (n=42) from Iassy county (Eastern Romania) collected in 2002-2003 from adolescents were analyzed for hexachlorocyclohexane (HCH) isomers, p,p'-DDT and its metabolites, hexachlorobenzene (HCB), chlordane and metabolites and 5 polychlorinated biphenyl (PCB) congeners. Very low levels were found for HCB and oxychlordane (0.8 and 2.5 ng g(-1)) indicating a low usage of these pesticide formulations in the studied area. In case of HCHs, gamma-HCH isomer was measured at higher median concentrations (79 ng g(-1) hair) compared to the beta-HCH isomer (55 ng g(-1)), which generally is the most prevalent from HCHs. The DDTs profile consisted in p,p'-DDE and p,p'-DDT which levels correspond to 81% of sum DDTs. Very high median concentrations measured for p,p'-DDT (192 ng g(-1)) combined with lower values for p,p'-DDE/p,p'-DDT of 0.4 (from 0.20 to 2.0) in all hair samples suggest recent exposure to "fresh" DDT. When gender was considered, significantly higher concentrations for most of the investigated contaminants were found in girls hair compared to boys. Very high levels were found in the present study for HCHs and DDTs compared to samples from Greece, Western Europe and China. In case of PCBs, the levels found in Romanian samples were found to be in the same range compared to other previously published data.

Research paper thumbnail of Cyanide Reaction with Ninhydrin: Elucidation of Reaction and Interference Mechanisms

Analytical Sciences, 2004

A new sensitive spectrophotometric method has recently been developed for the trace determination... more A new sensitive spectrophotometric method has recently been developed for the trace determination of cyanide with ninhydrin. Cyanide ion was supposed to act as a specific base catalyst. Nevertheless, this paper demonstrates that the reported assay is based on a novel reaction of cyanide with 2,2-dihydroxy-1,3-indanedione, which affords purple or blue colored salts of 2-cyano-1,2,3-trihydroxy-2H indene. Hydrindantin is merely an intermediary of the reaction. The formation of a stable and isolable ninhydrin-cyanide compound has been confirmed by its preparation in crystalline form. Also, it is thoroughly characterized by elemental as well as MS, IR, UV/VIS and 1 H NMR analyses. The Ruhemann's sequence of reactions of cyanide with ninhydrin has been reconsidered and an adequate mechanism of the reaction is proposed. As a consequence, the interference of oxidizers as well as copper, silver and mercury ions with the cyanide determination has been elucidated.

Research paper thumbnail of Apropiati va si va bucurati

Deci, ne-am îngropat cu El, în moarte, prin botez, pentru că, precum Hristos a înviat din morţi, ... more Deci, ne-am îngropat cu El, în moarte, prin botez, pentru că, precum Hristos a înviat din morţi, prin slava Tatălui, aşa să umblăm şi noi întru înnoirea vieţii; căci dacă am fost altoiţi pe El prin asemănarea morţii Lui, atunci vom fi părtaşi şi ai învierii Lui, cunoscând aceasta, că omul nostru cel vechi a fost răstignit împreună cu El, ca să se nimicească trupul păcatului, pentru a nu mai fi robi ai păcatului." (Romani 6;(3)(4)(5)(6).

Research paper thumbnail of Organochlorine contaminants in hair of adolescents from Iassy, Romania

Chemosphere, 2008

Human hair samples (n=42) from Iassy county (Eastern Romania) collected in 2002-2003 from adolesc... more Human hair samples (n=42) from Iassy county (Eastern Romania) collected in 2002-2003 from adolescents were analyzed for hexachlorocyclohexane (HCH) isomers, p,p'-DDT and its metabolites, hexachlorobenzene (HCB), chlordane and metabolites and 5 polychlorinated biphenyl (PCB) congeners. Very low levels were found for HCB and oxychlordane (0.8 and 2.5 ng g(-1)) indicating a low usage of these pesticide formulations in the studied area. In case of HCHs, gamma-HCH isomer was measured at higher median concentrations (79 ng g(-1) hair) compared to the beta-HCH isomer (55 ng g(-1)), which generally is the most prevalent from HCHs. The DDTs profile consisted in p,p'-DDE and p,p'-DDT which levels correspond to 81% of sum DDTs. Very high median concentrations measured for p,p'-DDT (192 ng g(-1)) combined with lower values for p,p'-DDE/p,p'-DDT of 0.4 (from 0.20 to 2.0) in all hair samples suggest recent exposure to "fresh" DDT. When gender was considered, significantly higher concentrations for most of the investigated contaminants were found in girls hair compared to boys. Very high levels were found in the present study for HCHs and DDTs compared to samples from Greece, Western Europe and China. In case of PCBs, the levels found in Romanian samples were found to be in the same range compared to other previously published data.

Research paper thumbnail of Cyanide Reaction with Ninhydrin: Elucidation of Reaction and Interference Mechanisms

Analytical Sciences, 2004

A new sensitive spectrophotometric method has recently been developed for the trace determination... more A new sensitive spectrophotometric method has recently been developed for the trace determination of cyanide with ninhydrin. Cyanide ion was supposed to act as a specific base catalyst. Nevertheless, this paper demonstrates that the reported assay is based on a novel reaction of cyanide with 2,2-dihydroxy-1,3-indanedione, which affords purple or blue colored salts of 2-cyano-1,2,3-trihydroxy-2H indene. Hydrindantin is merely an intermediary of the reaction. The formation of a stable and isolable ninhydrin-cyanide compound has been confirmed by its preparation in crystalline form. Also, it is thoroughly characterized by elemental as well as MS, IR, UV/VIS and 1 H NMR analyses. The Ruhemann's sequence of reactions of cyanide with ninhydrin has been reconsidered and an adequate mechanism of the reaction is proposed. As a consequence, the interference of oxidizers as well as copper, silver and mercury ions with the cyanide determination has been elucidated.

Research paper thumbnail of Apropiati va si va bucurati

Deci, ne-am îngropat cu El, în moarte, prin botez, pentru că, precum Hristos a înviat din morţi, ... more Deci, ne-am îngropat cu El, în moarte, prin botez, pentru că, precum Hristos a înviat din morţi, prin slava Tatălui, aşa să umblăm şi noi întru înnoirea vieţii; căci dacă am fost altoiţi pe El prin asemănarea morţii Lui, atunci vom fi părtaşi şi ai învierii Lui, cunoscând aceasta, că omul nostru cel vechi a fost răstignit împreună cu El, ca să se nimicească trupul păcatului, pentru a nu mai fi robi ai păcatului." (Romani 6;(3)(4)(5)(6).