The degree of substitution for sulfobutyl ether b-cyclodextrin (SBE-b-CD) has historically been characterized by nuclear magnetic resonance spectroscopy, but this approach provides gross values for the degree of substitution. The capillary electrophoresis method described here resolves the mixture of positional and regional isomers based on the degree of sulfo butyl ether substitution. Indirect UV detection has been used, where the detection of cyclodextrin is accomplished by a decrease in background absorbance of the background electrolyte buffer benzoic acid. Ten peaks of SBE-b-CD were well resolved with an optimum pH of 8.0 using an Agilent 50 μm id, 56 cm length bare fused silica capillary. The system suitability requirements were passed as per United States Pharmacopeia (USP), and acceptence criteria for averge degree of substitution 6.2 to 6.9 were met.
【设备更新】低盐湿腌发酵金鲳鱼加工过程中蛋白质和挥发性风味物质的变化Changes in Protein and Volatile Flavor Compounds Of Low-Salt Wet-Marinated Fermented Golden Pomfret Fish During Processing广东海洋大学食品科学与技术学院挥发性盐基氮和氨基酸态氮的检测:挥发性盐基氮的测定:按照GB 5009.228-2016,称重5g的鱼样本,使用格哈特Vapodest 450自动凯氏定氮仪检测。氨基酸态氮的测定:使用凯氏定氮法,2克样品加入40 mL 10 g/100 mL 三氯乙酸TCA,振荡样品30 min,过滤,用少量10 g/100 mL 三氯乙酸TCA洗涤沉淀。收集滤液后,用10 g/100 mL 三氯乙酸TCA将样品定容至100 mL,取20 mL使用格哈特红外消化仪进行消化,使用格哈特Vapodest 450自动凯氏定氮仪进行氮的测定。