离子色谱法同时测定植物生长调节剂中氯化胆碱、甲哌鎓及N-甲基哌啶

建立了一种离子色谱-抑制电导同时测定植物生长调节剂中主要活性成分氯化胆碱、甲哌鎓以及杂质N-甲基哌啶的快速检测方法。 样品经稀释过膜后直接进样分析， 采用阳离子交换色谱柱thermo scientific ionpac CG17 （50 mm×4 mm） + CS17 （250 mm×4 mm），以10 mmol·L^-1甲烷磺酸溶液等度淋洗，可在10 min内完成以上目标分析物的检测，且常规阳离子（Li⁺、 Na⁺、 NH₄⁺、 K⁺、 Mg²⁺和Ca²⁺）不会干扰对3种化合物的测定。 在优化后的最佳色谱条件下，氯化胆碱的线性范围为0.1~500 mg·L^-1，甲哌鎓的线性范围为0.5~500 mg·L^-1，N-甲基哌啶的线性范围为0.4~200 mg·L^-1，3种化合物线性相关系数（r）均大于0.999 4，线性关系良好。 3种目标分析物的检出限（信噪比S/N = 3）为28.0~112.5 μg·L^-1，定量限（信噪比S/N = 10）为93.5~375.0 μg·L^-1，峰面积的相对标准偏差（RSD， n = 6）均小于0.47%，表明方法具有较好的重现性。 该检测方法简单方便，已成功应用于商品化植物生长调节剂中3种成分质量浓度的测定，实际样品加标回收率为96.0%~103.6%。 可应用于相关植物生长调节剂原料及成品的质量控制。

Ion chromatographic method for simultaneous measurement of choline chloride,mepiquat chloride and N-methylpiperidine in plant growth regulators

This paper presents a rapid and simple method for simultaneous measure of the main active components choline chloride, mepiquat chloride, and the impurity N-methylpiperidine in plant growth regulators using ion chromatography with suppressed conductivity detection. According to this method,the samples are diluted in deionized water and then undergo a process of membrane filtration. The filtrate is directly injected into an ion chromatograph equipped with a commercially available cation-exchange column Thermo Scientific Ionpac CS17 (250 mm × 4 mm). The determination of target analytes can be finished in less than 10 min with an isocratic eluent consisting of 10 mmol·L^-1 methane sulfonic acid (MSA), and no interferences exist between common cations (Li⁺, Na⁺, NH₄⁺, K⁺, Mg²⁺ and Ca²⁺) and target analytes. Under the optimal conditions, the proposed method shows good linearity in the range from 0.1 to 500 mg·L^-1 for choline chloride, from 0.5 to 500 mg·L^-1 for mepiquat chloride and from 0.4 to 200 mg·L^-1 for N-methylpiperidine, with correlation coefficients (r) ≥ 0.999 4. Limits of detection (LODs, S/N = 3) are in the range from 28.0 to 112.5 μg·L^-1 and Limits of quantitation (LOQs, S/N = 10) are in the range from 93.5 to 375.0 μg·L^-1.It also has a good repeatability (RSDs ≤ 0.47%, n = 6). This method has been successfully applied to rapid and simultaneous analysis of the three compounds in commercial plant growth regulators. The overall average recoveries range from 96.0% to 103.6%. The proposed method can be applied to the quality control of raw materials and commercial products of plant growth regulator.