高效液相色谱法测定羟丙甲纤维素中亚硝酸盐含量

Content Determination of Nitrite in Hypromellose by HPLC

目的 建立测定羟丙甲纤维素中亚硝酸盐含量的高效液相色谱(HPLC)法。方法 优化羟丙甲纤维素的前处理方法。色谱柱为Agela Venusil HILIC亲水色谱柱(250 mm×4.6 mm,5μm),流动相为磷酸盐缓冲液(pH 3.8)-乙腈(50∶50,V/V),流速为1.0 mL/min,检测波长为205 nm,柱温为25℃,进样量为20μL。结果 采用水和乙腈为溶剂,交替递加使羟丙甲纤维素均匀溶胀,再用过量乙腈消溶胀并析出沉淀,制成亚硝酸盐溶液,多余乙腈经甲苯萃取浓缩。亚硝酸根离子质量浓度在25~1 000 ng/mL范围内与峰面积线性关系良好(R^(2)=0.999 9);检测限为10 ng/mL,定量限为25 ng/mL;精密度、稳定性、重复性试验结果的RSD均小于1.0%;平均加样回收率为99.16%,RSD为0.41%(n=9)。结论 优化的前处理方法可较好地避免羟丙甲纤维素在水中强烈的溶胀作用,有助于样品的充分提取。建立的HPLC法专属性强,结果准确可靠,可用于羟丙甲纤维素中亚硝酸盐的含量测定。

Objective To establish a high-performance liquid chromatography(HPLC) method for the content determination of nitrite in hypromellose.Methods The pre-treatment method of hypromellose was optimized.The chromatographic column was Agela Venusil HILIC hydrophilic chromatographic column(250 mm × 4.6 mm,5 μm),the mobile phase was phosphate buffer(pH 3.8)-acetonitrile(50 ∶ 50,V/V),the flow rate was 1.0 mL/min,the detection wavelength was 205 nm,the column temperature was 25 ℃,and the injection volume was 20 μL.Results With water and acetonitrile as the solvent,hypromellose was evenly swelled by alternating addition of them,and then excessive acetonitrile was used to eliminate the swelling of hypromellose and precipitate to make nitrite solution.The excess acetonitrile was extracted and concentrated by toluene.The linear range of nitrite ion was 25-1 000 ng/mL(R^(2)= 0.999 9).The limit of detection(LOD) was 10 ng/mL,and the limit of quantitation(LOQ) was 25 ng/mL.The RSDs of precision,stability and repeatability tests were lower than 1.0%.The average recovery of nitrite ion was 99.16% with an RSD of 0.41%(n = 9).Conclusion The optimized pre-treatment method can avoid the strong swelling effect of hypromellose in water,and is conducive to the full extraction of samples.The established HPLC method is specific,accurate,and reliable,which can be used for the content determination of nitrite in hypromellose.