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Bucharest, Romania

Popa C.-V.,University of Bucharest | Danet A.F.,University of Bucharest | Jipa S.,INCDE ICPE CA | Zaharescu T.,INCDE ICPE CA
Revista de Chimie | Year: 2010

Total antioxidant capacity (TAC) of several samples of red and white wines was investigated by means of a new analysis method of flow injection with chemiluminescence detection ((FIA-CL). The applied method is based on a chemiluminescence reaction between luminol and hydroxyl radicals generated by the hydrogen peroxide in the presence of Co(II) ions complexed with ethylene diamine tetraacetic acid (EDTA) disodium salt according to a Fenton-type reaction. The FIA-CL assembly is made of three channels through which corresponding liquids are pumped: a carrier flux of 0.05M, pH 9 sodium borate solution where the analyzed sample is injected, a H2O2 flux and a flux containing CL reagent, that is a Co(II)/EDTA/luminol solution. This method allows for TAC determination within 2.5-300 μmoles L -1domains of gallic and caffeic acid, and with a relative standard deviation (RSD) = 2.41% (n = 10) when gallic acid concentration is 35 μM. The TAC values determined for the analyzed wine samples ranged between 0.19 and 0.55 g of gallic acid equivalents/L wine and between 0.44 and 1.78 g caffeic acid equivalents/L wine. Source


Popa C.-V.,University of Bucharest | Danet A.F.,University of Bucharest | Jipa S.,INCDE ICPE CA | Zaharescu T.,INCDE ICPE CA
Revista de Chimie | Year: 2012

Total antioxidant capacity (TAC) of juices obtained from apples, pear, banana, kiwi fruit, lemon, orange, cranberry and sea buckhorn and seven commercial noncarbonated soft drinks was investigated by using a flow injection analysis with chemiluminescence detection (FIA-CL) method. This method allows TAC determination within 0.8-300 micromoles L -1 domains of L-ascorbic and uric acids. A relative standard deviation (RSD) was up to 3% (n = 10,c = 8 μM uric acid and 20 μM L-ascorbic acid). TAC determined for the analyzed juices samples was between 3.96 and 37.5 milligrams of L-ascorbic acid equivalents/100 g fresh fruits. Berries juices were also analyzed after being kept for 24 h since preparation at room temperature in properly sealed vessels and found that TAC values decrease by approximately 40%. The TAC values determined for the analyzed noncarbonated soft drinks vary between 5.46-66.9 mg L-ascorbic acid equivalents/100 mL samples and between 3.20 and 104 mg uric acid equivalents/100 mL samples. Source


Popa C.-V.,University of Bucharest | Farcasanu I.-C.,University of Bucharest | Jipa S.,INCDE ICPE CA | Zaharescu T.,INCDE ICPE CA | Danet A.F.,University of Bucharest
Revista de Chimie | Year: 2012

Total antioxidant capacity (TAC) of some Rosmarinus officinalis L (rosemary) extracts was investigated by an "in batch" analytical method based on chemiluminescence (CL). This method is based on a CL reaction between luminol and hydroxyl radicals generated by the hydrogen peroxide in the presence of Co(II) ions complexed with ethylene diamine tetraacetic acid (EDTA) disodium salt, according to a Fenton-type reaction. The method allows for TAC determination in 1 × 10 -5 - 2.5 10 -3 moles L -1 domain of gallic acid concentration and with a relative standard deviation (RSD) =2.53%(n = 10) for 8 × 10 -4 M gallic acid concentration. The TAC values determined for the analyzed rosemary extracts ranged between 1.6 and 4.58 grams of gallic acid equivalents/100 g dw plant. The employed analytical method was verified by applying the standard addition method and a good precision was established. Source

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