固相萃取-液相色谱法测定婴幼儿配方乳粉中的游离核苷酸

该文建立了婴幼儿配方乳粉中5种游离核苷酸的检测方法。婴幼儿配方乳粉经乙二胺四乙酸二钠和氯化钠溶液提取，强阴离子（SAX）固相萃取柱净化，通过反相Atlantis T₃色谱柱分离，二极管阵列检测器检测，外标法定量。结果表明：方法抗干扰能力强、准确度高，尤其对羊奶粉净化效果好、分离度高。5种游离核苷酸在0.5~10 mg/L范围内线性关系良好（r≥0.999）；添加水平在0.05~0.50 g/kg时，回收率为91.1%~112%，相对标准偏差为2.3%~4.7%；检出限为0.0010~0.0015 g/kg，定量限为0.0030~0.0045 g/kg。对乳粉质控样品进行检测，结果与中位值比较的偏差在10%以内。该方法可为监管部门提供技术支持，为乳品行业健康发展提供保障。

Determination of free nucleotides in infant formula by solid phase extraction-liquid chromatography

A method for the determination of five free nucleotides in infant formula was established. The analytes were extracted by ethylene diamine tetraacetic acid and sodium chloride solution, and purified by strong anion exchange (SAX) solid-phase extraction. An Atlantis T₃ reverse-phase column was applied to separate the five free nucleotides. A high performance liquid chromatography (HPLC) system equipped with a diode array detector was applied to detect the target compound, and a series of external standards were used for quantification. Good linearities (r≥0.999) were observed, with the range of 0.5-10 mg/L for the five free nucleotides. When the addition levels were 0.05-0.50 g/kg, the recoveries were between 91.1% and 112%, and the precisions were between 2.3%-4.7%. The limits of detection (LODs) and the limits of quantification (LOQs) for the five free nucleotides ranged from 0.0010 to 0.0015 g/kg and from 0.0030 to 0.0045 g/kg. In conclusion, the proposed method has several merits. First, the high accuracy and precision indicated that the quality control sample had a relative deviation of less than 10% to the median. Second, perfect anti-disturbance was observed for the complex goat milk powder. Thus, this method can provide technical support for supervision departments and guarantees healthy development of the dairy industry.