Abstract:Fruit spirits contain a large array of volatile compounds among which the important role from toxicological aspect besides ethanol has methanol, aliphatic esters and fusel alcohols. This study evaluates the content of ethanol, ethyl acetate, methanol, isopropyl alcohol (2-propanol), n-propyl alcohol (propan-l-ol), isobutyl alcohol (2-methylpropan-1-ol), n-butyl alcohol (1-butanol), isoamyl alcohol (3-methyl-1-butanol) and n-amyl alcohol (pentan-1-ol) in different grapes and plum brandies industrially produced at Republic of Macedonia. Gas chromatography (GC) with flame ionization detection (FID) was applied for the characterization of all investigated volatile compounds. The obtained results revealed that the highest methanol content was present in the samples of plum brandy, which is mainly due to the higher content of pectin in the raw material. The most important higher alcohols of grape and plum brandies were found to be: n-propyl alcohol, isobutyl alcohol and isoamyl alcohol. In all the analyzed samples of grape and plum brandies, the most abundant was isoamyl alcohol which content ranged from 50.3 to 290.7 mg/100 mL a.a. Comparing the results with the data from the literature, it can be concluded that the concentrations of all investigated volatile compounds in the samples of grape and plum brandies are commonly acceptable.

Abstract:The method for simultaneous determination of 20 organophosphorus pesticide residues in corn samples has been developed and validated. For the extraction of organophosporus pesticide residues from the samples, the accelerated solvent technique with the mixture of dichloromethane: acetone (1:1, V/V) was used. Clean up was done using liquid -liquid extraction with n -hexane, followed by solid phase extraction on primary secondary amine adsorbent, and elution with the mixture of acetone: toluene (65:35). The determination of the pesticides was carried out by gas chromatography with nitrogen phosphorus detection. Separation and quantitative determination of the analytes were performed on a fused silica capillary ZB-35 column (30 m x 0.25 mm i.d. x 0.25 µm, Phenomenex). The recovery was investigated in blank corn samples fortified with mevinphos, diazinon, dimethoate, bromofos-methyl, chlorfenvinphos, fenamiphos, ethion and phosalone at 5 ng/g, 10 ng/g, 15 ng/g , 20 ng/g and 25 ng/g, respectively and with methacrifos, phorate, etrimfos, parathion-methyl, pirimiphosmethyl, fenitrothion, chlorpyrifos, malathion, parathion, bromofos-ethyl, phosmet and azinphos-methyl at 10 ng/g, 20 ng/g, 30 ng/g, 40 ng/g and 50 ng/g, respectively. The recovery ranged from 76.0% to 112.0%. Repeatability expressed as relative standard deviation (RSD) was less than 8.2%. Linearity expressed as correlation coefficient (R 2 ) ranged from 0.9935 to 0.9996. Measurement uncertainty (U x ) was lower than 14.2% for all tested pesticides. The limits of quantification (LOQ) were bellow 5 ng/g for all tested pesticides. The satisfactory Z-score results of international proficiency tests confirm good analytical performances of the developed method.

Abstract:The present study investigates the total arsenic (As) content in the samples of drinking water in the Republic of Macedonia, which is obtained from different water sources, such as: springs, surface accumulations, underground accumulations and drilled wells. From January 2013 to December 2013, a total of 780 samples obtained from the public water supply systems at 35 measurement points distributed throughout the whole territory of the Republic of Macedonia were analyzed on the total As content. A flow injection atomic absorption spectrometry (FIAS) was employed for the determination of the total As content after wet digestion of the samples with nitric acid (67%, W/V) and hydrogen peroxide (30%, V/V). The results of the study revealed that in 96.7% of the tested samples, As content was below established maximum allowable concentration (MAC) of 10 µg/L. As concentrations up to 26.4 µg/L were found in the samples of drinking water that comes from the water sources located in the vicinity of Kozhuf Mountain, which is due to the mineral composition of the mountain body rich with As containing minerals: lorandite, orpiment, realgar, arsenopyrite etc. Higher As concentrations (5.47 µg/L -26.6 µg/L) were also found in the samples of drinking water obtained from the water supply system of the towns from the Dojran Municipality which are located in the vicinity of thermal-mineral area of Mala Boshka -Toplec. It can be concluded that the presence of total As in the potable water in the Republic of Macedonia comes only from natural sources.

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