柱前衍生高效液相色谱法测定二乙醇胺脱氢产物亚氨基二乙酸和甘氨酸

以对甲苯磺酰氯(PTSC)为衍生剂,建立了柱前衍生高效液相色谱(HPLC)测定二乙醇胺脱氢产物中亚氨基二乙酸(IDA)和甘氨酸(Gly)含量的分析方法。IDA和Gly与衍生剂在碱性(pH 11)条件下于45℃反应15 min,进行柱前衍生,并利用高效液相色谱-质谱对衍生产物进行定性分析。衍生化产物采用VP-ODS色谱柱(200 mm×4.6 mm,5μm)分离,以0.03 mol/L醋酸铵溶液(pH 5.5)为流动相A、乙腈为流动相B(体积比为87∶13),进行等度洗脱,流速为1 mL/min,并采用配有紫外检测器的高效液相色谱仪测定,检测波长为235 nm。该法在IDA质量浓度为900~2 100 mg/L、Gly质量浓度为20~100 mg/L的范围内线性关系良好,相关系数(R2)均大于0.999。IDA和Gly的检出限(LOD)分别为0.089 7 mg/L和0.026 2 mg/L,加标回收率分别为98.7%~99.3%和98.0%~99.5%,相对标准偏差(RSD)分别为0.89%~1.23%和0.95%~1.11%(n=3)。该法具有反应条件温和、准确性高的特点,可用于工艺生产中IDA和Gly含量的测定。

Determination of iminodiacetic acid and glycine in dehydrogenation products of diethanolamine by pre-column derivatization and high performance liquid chromatography

An analytical method was developed for the determination of iminodiacetic acid (IDA) and glycine (Gly), the dehydrogenation products of diethanolamine, by high performance liquid chromatography (HPLC) coupled with pre-column derivatization using p-toluenesulfonyl chloride (PTSC) as the derivatization reagent. IDA and Gly reacted with PTSC in the alkaline environment (pH 11) under 45℃ for 15 min. Then the derivatization products were analyzed by HPLC-MS. The separation was carried out on a high performance liquid chromatograph equipped with an ultraviolet detector. A VP-ODS column (200 mm×4.6 mm, 5 μm) was employed using 0.03 mol/L ammonium acetate (pH 5.5)-acetonitrile (87:13, v/v) as mobile phases for isocratic elution at a flow rate of 1 mL/min and detection wavelength of 235 nm. The results showed good linearities for iminodiacetic acid of 900-2100 mg/L, and for glycine of 20-100 mg/L, respectively. The linear correlation coefficients (R²) were both greater than 0.999. The limits of detection (LODs) of IDA and Gly were 0.0897 mg/L and 0.0262 mg/L and the recoveries were in the range of 98.7%-99.3% and 98.0%-99.5%, respectively. The relative standard deviations (RSDs) of IDA and Gly were in the range of 0.89%-1.23% and 0.95%-1.11% (n=3). The method has the characteristics of mild reaction conditions and high accuracy, and is well suitable for the determination of IDA and Gly in industrial production.