离子色谱-紫外检测法测定饲料中的胍基乙酸

通过对色谱柱、流动相洗脱、样品前处理等条件进行优化,建立了一种检测饲料中胍基乙酸含量的离子色谱法。在甲磺酸线性梯度洗脱条件下,样品经Dionex IonPacTMCS16阳离子交换柱分离,用紫外检测器于200 nm波长处进行检测。在0.5~200 mg/L范围内,中胍基乙酸色谱峰面积与质量浓度呈良好的线性关系(相关系数r2=0.999 9)。配合饲料和浓缩饲料中胍基乙酸的检出限为4.5 mg/kg、定量限为15 mg/kg,复合预混合饲料中胍基乙酸的检出限为9.0 mg/kg、定量限为30 mg/kg。该方法对添加量在15 mg/kg~60 g/kg范围内的禽用配合饲料、猪用配合饲料、浓缩饲料、复合预混合饲料中胍基乙酸的回收率均大于94%。该方法性能指标可满足饲料中胍基乙酸含量的检测需求。

Determination of guanidinoacetic acid in feed by ion chromatography coupled with ultraviolet detection

A novel ion chromatography method for the determination of guanidinoacetic acid (GAA) in animal feed samples was developed. The optimal detection mode, chromatography column, gradient condition of mobile phases and sample pretreatment conditions were investigated. Using a linear gradient of methane sulfonic acid and ultraviolet detector at 200 nm, the interfering substances in feed samples and GAA could be separated successfully on a Dionex IonPac^TM CS16 cation exchange analysis column. The calibration curves showed a range of linearity between 0.5 and 200 mg/L, and a high linear regression coefficient of 0.9999 was obtained for GAA. The limits of detection and limits of quantification of GAA in formula feed and concentrate feed were 4.5 and 15 mg/kg, respectively. The limit of detection and limit of quantification of GAA in compound-premix were 9.0 and 30 mg/kg, respectively. The recoveries of this method for GAA were investigated, and the recoveries were all more than 94% in formula feed, concentrate feed and compound-premix feed for pig and poultry. This method can meet the requirements of the determination of GAA in feed samples for the feed production enterprise and evaluation center.