Boussenadji R, Porthault M, Berthod A
Laboratoire des Sciences Analytiques, UA CNRS 435, Université de Lyon 1, Villeurbanne, France.
J Pharm Biomed Anal. 1993 Jan;11(1):71-8. doi: 10.1016/0731-7085(93)80150-y.
Antioxidants are added to foods and drugs to inhibit their oxidation. As these additives are somewhat toxic, it is necessary to control the amount added to any food or drug. Liquid chromatography (LC) is a powerful tool for this purpose. Many antioxidants are electroactive molecules which enables the advantages of electrochemical detection or selectivity and sensitivity to be realized. The interest of analysts in microbore LC arises from the low mobile phase volumetric flow rates involved, the reduced on-column samples together with reduced chromatographic dilution and high efficiency. Coupling of microbore LC with electrochemical detection adds another advantage: the decrease of electrode ageing. The problem of extra-column band broadening with microbore column is discussed in the present communication. A micro LC-electrochemical detection system is constructed and tested using catecholamines. The limit of detection (LOD) for noradrenaline using a 0.7 mm bore column is found to be 0.1 pg injected in 0.2 microliter (0.6 femtomoles). Three phenolic antioxidants are studied: tert-butyl-p-hydroxyanisole (BHA), di-tert-butyl-hydroxytoluene (BHT) and n-propyl gallate (3,4,5-trimethoxybenzoic acid propyl ester). The dynamic range is four orders of magnitude with LODs down to 0.1 femtomoles (20 fg injected) with a 0.3 mm bore column. No electrode response change is observed after 60 injections of 3 ng BHA over 6 days. Antioxidants are determined in different pharmaceutical preparations and foodstuffs (chewing gums, dried potato flakes). The agreement between the manufacturer stated concentrations and observed results is found to be satisfactory.
抗氧化剂被添加到食品和药物中以抑制其氧化。由于这些添加剂具有一定毒性，因此有必要控制添加到任何食品或药物中的量。液相色谱法（LC）是实现这一目的的有力工具。许多抗氧化剂是电活性分子，这使得电化学检测的优势以及选择性和灵敏度得以实现。分析人员对微径液相色谱感兴趣，是因为其涉及的流动相体积流速较低、柱上进样量减少、色谱稀释降低以及效率较高。将微径液相色谱与电化学检测相结合还具有另一个优势：电极老化的减少。本文讨论了微径柱的柱外谱带展宽问题。构建了一个微径液相色谱 - 电化学检测系统，并使用儿茶酚胺进行了测试。使用内径为0.7毫米的色谱柱时，去甲肾上腺素的检测限（LOD）为在0.2微升（0.6飞摩尔）中注入0.1皮克。研究了三种酚类抗氧化剂：叔丁基对羟基茴香醚（BHA）、二叔丁基对甲酚（BHT）和没食子酸丙酯（3,4,5 - 三甲氧基苯甲酸丙酯）。使用内径为0.3毫米的色谱柱时，动态范围为四个数量级，检测限低至0.1飞摩尔（注入20皮克）。在6天内对3纳克BHA进行60次进样后，未观察到电极响应变化。在不同的药物制剂和食品（口香糖、干土豆片）中测定了抗氧化剂。发现制造商声明的浓度与观察结果之间的一致性令人满意。
