HPLC-DAD测定饲用酸化剂苯甲酸中7种邻苯二甲酸类杂质

Determination of Seven Phthalic Acid Impurities in Feed Acidifier Benzoic Acid by HPLC-DAD

为了建立高效液相色谱法测定饲用酸化剂苯甲酸中邻苯二甲酸、2-羟基苯甲酸、3-羟基苯甲酸、4-羟基苯甲酸、2-甲基苯甲酸、3-甲基苯甲酸和4-甲基苯甲酸共7种邻苯二甲酸类杂质的方法。本试验将酸化剂样品溶于甲醇和初始流动相的混合溶液中,采用Agilent ZORBAX SB-C18色谱柱(4.6 mm×250 mm,5.0μm)分离7种邻苯二甲酸类杂质,以水-乙腈-甲基磺酸(85-15-0.1)和乙腈为流动相进行梯度洗脱,流速为1.2 mL/min,采用二极管阵列检测器(DAD),采集波长范围为210~400 nm,记录扫描光谱图和235 nm波长处的色谱图。用外标法定量邻苯二甲酸类杂质的含量。结果显示,7种邻苯二甲酸类杂质的浓度在0.10~40.00μg/mL范围内的线性良好,平均加标回收率在98.5%~102.7%范围内,相对标准偏差(RSD,n=5)介于0.3%~1.5%,检测限和定量限均为4 mg/kg。本试验建立的酸化剂苯甲酸中7种邻苯二甲酸类杂质的高效液相色谱-二极管阵列检测器(HPLC-DAD)检测方法快速且准确,可用于苯甲酸中7种邻苯二甲酸类杂质的定性和定量检测。

To develop a high-performance liquid chromatography(HPLC)method to determine the presence of seven phthalic acid impurities in feed acidifier benzoic acid.The impurities include phthalic acid,2-hydroxybenzoic acid,3-hydroxybenzoic acid,4-hydroxybenzoic acid,2-methylbenzoic acid,3-methylbenzoic acid,and 4-methylbenzoic acid.The acidifier samples were dissolved in a mixture of methanol and the initial mobile phase.An Agilent ZORBAX SB-C18 column(4.6 mm×250 mm,5.0μm)was used to separate the seven impurities,with a gradient elution of water-acetonitrile-methanesulfonic acid(85-15-0.1)and acetonitrile as the mobile phases at a flow rate of 1.2 mL/min.The diode array detection(DAD)was set to collect data in the wavelength range of 210-400 nm,recording the UV spectra and chromatograms at 235 nm.The content of phthalic acid impurities was quantified using the external standard method.The results showed good linearity for the seven impurities within the concentration range of 0.10 to 40.00μg/mL.The average recovery rates were between 98.5%and 102.7%,with relative standard deviations(RSD,n=5)ranging from 0.3%to 1.5%.The detection limit and quantification limit were both 4 mg/kg.The HPLC-DAD method developed in this study is rapid and accurate for the qualitative and quantitative determination of seven phthalic acid impurities in benzoic acid.