软饮料（果汁、汽水）和酒精饮料中有机酸（乙酸、柠檬酸、甲酸、乳酸、苹果酸、草酸、琥珀酸、酒石酸）检测方案(毛细管电泳仪)

HIGH PERFORMANCECAPILLARYELECTROPHORESIS SYSTEM DETERMINATION OF ORGANIC ACIDS IN BEVERAGES LUMEX Method M 04-47 (2007) INTRODUCTION The method allows determination of organic acids， in soft drinks (juices， fizz drinks) and alcoholic drinks(wines， beer). MEASUREMENT METHOD The method is based on differential migration and separation of anions of organic acids in electric field dueto their different electrophoretic mobility. Identification and quantitative determination of the analyzed components are performed by detecting theoptical density of a solution at 254 nm wavelength. MEASUREMENT RANGE Acids Measurement range， mg/L Acetic acid 1.0-2000 Citric acid 1.0-10000 Formic acid 1.0-500 Lactic acid 1.0-5000 Malic acid 1.0-10000 Oxalic acid 1.0-500 Succinic acid 1.0-2000 Tartaric acid 1.0-6000 Inorganic anions (chloride， nitrite， sulphate， nitrate， fluoride， phosphate， carbonate)， ascorbic acid， andpreservatives (benzoic and sorbic acids) do not influence the determination of analyzed organic acids. EQUIPMENT AND REAGENTS The"CAPEL” capillary electrophoresis system with high-voltage negative polarity is used in measurements.Data acquisition， collection， processing and output are performed using a personal computer running under"WINDOWS 2000/XP”operating system with installed dedicated software package for acquisition andprocessing of chromatography data. EXAMPLES OF REAL ANALYSES Buffer：benzoic acid， with DEA， CTAB， and disodium EDTACapillary：LEFF/LTOTAL 50/60 cm， ID 75 pmInjection：150 mbar x secVoltage：-20kVDetection：254 nm， indirect Sample： test solution of o3rganic acids.5 mAU and phosphate (10 mg/L of each acid)： 1- oxalic acid 9 2 - formic acid 3- tartaric acid 4 - malic acid 10 5- citric acid 6 - succinic acid 7 - lactic acid 8- phosphate (as hydrophosphate) 9 - acetic acid 10 - propionic acid 2 3 min Sample： dark beer (dilution 1：19) Measurement results： 1 -oxalic acid (9.8 mg/L) 2 - malic acid (82.3 mg/L) 3 - citric acid (148 mg/L) 4 - succinic acid (46.2 mg/L) 5 - lactic acid (67 mg/L) 6 - phosphate (as hydrophosphate) 7 - acetic acid (107 mg/L) Sample： dry white wine (dilution 1：49) Measurement results： 1 - tartaric acid (1415 mg/L 2 - malic acid (1643 mg/L) 3 - citric acid (465 mg/L) 4 -succinic acid (500 mg/L) 5 - lactic acid (1165 mg/L) 6- phosphate (as hydrophosphate) 7 - acetic acid (405 mg/L) Sample： cherry juice (dilution 1：99) Measurement results： 1 - malic acid (2725 mg/L) 2 - citric acid (3054 mg/L) 3 -lactic acid (112 mg/L) 4-phosphate (as hydrophosphate) ADVANTAGES OF CAPILLARY ELECTROPHORESIS Compared with determination of organic acids in beverages samples by HPLC method， capillaryelectrophoresis has several advantages： high separation efficiency； low analysis cost； absence of an expensive chromatographic column； short analysis time. The contents on this paper are subject to change without notice. WWW.LUMEX.BIZ LUMEX成功的将毛细管电泳发展成为实验室的常规分析手段，并一直占据该领域的市场领导地位。成熟的仪器、优化的配置、大量的应用方法包集于一体，被用户称为目前性价比最优的分析仪器。该方法允许适用于测定软饮料（果汁，汽水饮料）和酒精饮料（葡萄酒，啤酒）中的有机酸（乙酸、柠檬酸、甲酸、乳酸、苹果酸、草酸、琥珀酸、酒石酸）。毛细管电泳法的分析优势特点有：1.高效分离效率(百万级理论塔板数)；2.样品试剂和样品量消耗低；3.极低的分析成本，毛细管柱一般无需更换；4.操作简单便捷，实现快速分析 (5-10分钟)。