比久农药中游离偏二甲肼的高效液相色谱快速测定

Quick determination of unsymmetrical dimethyl hydrazine in B9 by HPLC

建立了用甲醛衍生测定农药比久样品中微量的偏二甲肼的方法。采用甲醛与偏二甲肼柱前衍生,在室温、中性溶液中反应10 min,生成确定量的有较强紫外吸收的偏二甲腙,不须富集可直接用HPLC法测定偏二甲肼。研究了甲醛与偏二甲肼的反应条件及产物的光谱特征,测得衍生物的最大吸收波长λmax=237 nm和表观摩尔吸光系数ε=3.6×10^3（L.mol^-1.cm^-1）,选定ZorbaxODS色谱柱,V（磷酸盐缓冲溶液,pH 7）∶V（甲醇）=94∶6为流动相,检测波长为237 nm。结果表明：在0.56-960μg/mL范围内回归方程为：A=0.4677ρ-0.2790,R^2=0.9998,检出限为1.3μg/g,回收率为97.5%-103.4%,相对标准偏差为0.9%-1.8%。

A new derivative reagent of high performance liquid chromatography was introduced for the determination of the residual unsymmetrical dimethyl hydrazine（UDMH） in B9.The method is based on the pre-column derivatization of UDMH with formaldehyde.The derivatization reaction proceeds in neutral aqueous solution at room temperature.Stable derivative was formed within 10 min.Spectrometric properties of the derivative have also been studied.The maximum absorbance wavelength and the apparent molar absorbativity were 237 nm and 3.6×10^3（L·mol^-1·cm^-1）,respectively.The mixture of monobasic sodium phosphate（pH 7）-methanol（94∶6 V/V） was used as mobile phase.The UV detection wavelength was 237 nm.The limit of detection（LOD） was 1.3 μg/g,the recovery were 97.5%～103.4%,and RSDs were 0.9%～1.8%.Standard calibration curve for UDMH was linear（r2=0.9998） over the concentration range of 0.56～960 μg/mL.This method had been successfully proved to be simple,fast and reliable.