Abstract Ethephon is approved in the European Union as a plant growth regulator and used in plant protection products. The available methods for the assay of ethephon in pesticide formulations demand decomposition of ethephon to ethene under alkaline conditions, and subsequently either titration by acidimetry or gas chromatography with flame ionization detection. The present work proposes two novel anion exchange high-performance liquid chromatographic methods with indirect spectrophotometric detection for the assay of ethephon in plant protection formulations, with a quick and simple sample preparation, involving only weighing and diluting the sample with water before injection. The study involved optimization of the pH, the concentration of a chromophore compound as the mobile phase modifier and the optimization of the mobile phase flow rate. The first method used a strong anion exchange column (250 mm × 4 mm, 10 µm, 300 Å) with isocratic elution with an aqueous mobile phase consisted of 1 mM potassium hydrogen phthalate at pH 7 by the addition of 0.6 M aqueous KOH using a 1.4 mL/min flow rate. The second approach also used a strong anion exchange column (250 mm × 4.6 mm, 5 µm, 80 Å) with isocratic elution with an aqueous mobile phase composed of 1.2 mM phthalic acid, 6 mM monopotassium phosphate and 4% (v/v) methanol at pH 2 by the addition of H3PO4 and 2 mL/min flow rate. The two methods were validated, applied in commercial samples and were shown to be equivalent after statistical comparison. They are considered applicable for the quality control of ethephon content in soluble concentrate formulations and surpass the existing laborious and time-consuming methods which demand decomposition of ethephon to ethene.

中文翻译：

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使用间接分光光度检测的离子交换色谱法测定农药制剂中的乙烯利

摘要 乙烯利在欧盟被批准用作植物生长调节剂并用于植物保护产品。测定农药制剂中乙烯利的现有方法需要在碱性条件下将乙烯利分解为乙烯，然后通过酸度法或气相色谱法进行滴定和火焰离子化检测。目前的工作提出了两种新型阴离子交换高效液相色谱方法，采用间接分光光度法检测植物保护制剂中乙烯利的测定，样品制备快速简单，只需在注射前称重和用水稀释样品。该研究涉及 pH 值的优化、作为流动相改性剂的发色团化合物的浓度以及流动相流速的优化。第一种方法使用强阴离子交换柱 (250 mm × 4 mm, 10 µm, 300 Å) 等度洗脱，流动相由 1 mM 邻苯二甲酸氢钾组成，pH 7，通过添加 0.6 M KOH 水溶液，使用1.4 毫升/分钟的流速。第二种方法还使用强阴离子交换柱（250 mm × 4.6 mm、5 µm、80 Å），等度洗脱，流动相由 1.2 mM 邻苯二甲酸、6 mM 磷酸二氢钾和 4% (v/v) 组成通过添加 H3PO4 和 2 mL/min 的流速在 pH 2 的甲醇。这两种方法经过验证，应用于商业样品，经统计比较后显示等效。