کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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1243197 | 1495839 | 2012 | 7 صفحه PDF | دانلود رایگان |
A new flow-injection (FI) and high performance liquid chromatography (HPLC) with chemiluminescence detection method has been proposed for the determination of α-lipoic acid (LA). The assay is based on the measurement of chemiluminescence (CL) produced during the reaction of α-lipoic acid with potassium permanganate in a sodium hexametaphosphate medium (pH 3). This reaction is accompanied by a weak CL, which is greatly increased in the presence of a formaldehyde solution. The proposed FI method allows the determination of LA over the range: 0.5–20 μg mL−1 with LOD 4 × 10−3 μg mL−1. An introduction of HPLC into the flow manifold improves selectivity of the method and allows the determination of LA in a complex sample. The chromatographic linear range is 2.5–30 μg mL−1 with LOD 1.774 μg mL−1. Chromatographic separation was achieved by isocratic elution (acetonitrile/potassium dihydrogen phosphate, pH 3, adjusted with phosphoric acid): 30/70 using a Cosmosil 5C18-MS-II (4.6 mm × 150 mm I.D.) column at a flow rate of 1.0 mL min−1. The presented methods were utilized to determine the α-lipoic acid content in “Alfa-lipoic acid” capsules and in food products.
► Developing a new flow-injection chemiluminescence method for the determination of α-lipoic acid.
► The integration of HPLC separation of the lipoic acid with CL detection flow system.
► Optimization of the composition of the chromatographic mobile phase which had to be adjusted to the CL-detector.
► Application flow manifold with CL detection coupled to HPLC system for the determination of lipoic acid in food samples.
Journal: Talanta - Volume 96, 15 July 2012, Pages 223–229