SPECTROPHOTOMETRIC DETERMINATION OF REDUCING SUGAR IN WINES EMPLOYING IN-LINE DIALYSIS AND A MULTICOMMUTED FLOW ANALYSIS APPROACH
ABSTRACT A multicommuted flow procedure for the spectrophotometric determination of reducing sugars in wine has been developed. A dialysis unit was incorporated in the system to minimize matrix interferences and eliminate the colored compounds of the wine. The oxidation-reduction reaction in an alkaline medium between reducing sugars and the Cu2+-Neocuproine complex was employed. The compound formed was monitored at 460 nm. In the proposed procedure, there was a linear response between 0.25 and 4.0 g L-1 reducing sugars (y = (0.36 ± 0.02) + (0.31 ± 0.01) * x, R = 0.9975, n = 6), a coefficient of variance of 2.6% for a reducing sugar solution of 2.0 g L-1 (n = 7), a limit of detection estimated at 0.03 g L-1, reagent consumption per determination of 0.330, 0.128 and 0.160 mg for neocuproine, CuSO4 and NaOH, respectively. A sampling throughput of 45 determinations per hour was achieved. The proposed system was applied to wine samples and comparing the results with an AOAC official method no significant difference at a 95% confidence level.
| Main Authors: | , , , |
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| Format: | Digital revista |
| Language: | English |
| Published: |
Sociedad Chilena de Química
2018
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| Online Access: | http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-97072018000203994 |
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| Summary: | ABSTRACT A multicommuted flow procedure for the spectrophotometric determination of reducing sugars in wine has been developed. A dialysis unit was incorporated in the system to minimize matrix interferences and eliminate the colored compounds of the wine. The oxidation-reduction reaction in an alkaline medium between reducing sugars and the Cu2+-Neocuproine complex was employed. The compound formed was monitored at 460 nm. In the proposed procedure, there was a linear response between 0.25 and 4.0 g L-1 reducing sugars (y = (0.36 ± 0.02) + (0.31 ± 0.01) * x, R = 0.9975, n = 6), a coefficient of variance of 2.6% for a reducing sugar solution of 2.0 g L-1 (n = 7), a limit of detection estimated at 0.03 g L-1, reagent consumption per determination of 0.330, 0.128 and 0.160 mg for neocuproine, CuSO4 and NaOH, respectively. A sampling throughput of 45 determinations per hour was achieved. The proposed system was applied to wine samples and comparing the results with an AOAC official method no significant difference at a 95% confidence level. |
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