油井采出水中十二烷基苯磺酸盐高效液相色谱检测 方法的改进*

为降低高效液相色谱法中高浓度无机盐的不利影响,以低浓度的醋酸铵(NH₄Ac)水溶液/甲醇混合液代替高浓度的NaH₂PO₄水溶液/甲醇混合液,对油井采出水中十二烷基苯磺酸盐的高效液相色谱检测方法进行改进,对测试条件进行了优选,并与质谱联用。结果表明,最佳测试条件为:10 cm×4.6 mm阴离子交换色谱柱,流动相为20 mmol/L NH₄Ac水溶液/甲醇混合液(体积比2∶3),流速1.0 mL/min,等度洗脱,紫外检测波长225 nm,20μL进样。该方法抗干扰能力较好,在5~500 mg/L范围内的线性关系良好,线性相关系数R=0.9997,检出限2 mg/L,在12 min内完成一次分析,具有准确、快速、灵敏的特点,可以用于油井采出水中十二烷基苯磺酸盐的定量检测。此外,该方法可以与质谱直接联用,分析十二烷基苯磺酸盐的结构信息。

Method Improvement of Dodecylbenzene Sulfonate Detection in Oilfield Produced Water via High Performance Liquid Chromatography

In order to avoid the disadvantage of inorganic salt with high concentration,the detection method of dodecylbenzene sulfonate in oilfield produced water was improved by using ammonium acetate(NH₄Ac)aqueous solution at a low concentration mixed with methanol instead of the original NaH₂PO₄ aqueous solution at a high concentration mixed with methanol.The detection parameters were optimized,and the method was combined with mass spectra.The results showed that the optimal condition was obtained as follows:a 10 cm×4.6 mm anion exchange chromatographic column,20 mmol/L NH₄Ac aqueous solution and methanol in volume ratio 2∶3 as mobile phase,1.0 mL/min flow velocity with isocratic elution,225 nm ultraviolet detection wavelength,and 20μL injection volume.This method showed good anti-interference ability and well linearity in the range of 5—500 mg/L.The coefficient R was 0.9997 and the detection limit was 2 mg/L.Furthermore,one analysis was finished in 12 min.In general,this method showed the characteristics of accuracy,high speed and sensitivity,and could satisfy the quantitative detection of dodecylbenzene sulfonate in oilfield produced water.Moreover,the method could be directly coupled with mass spectra to analyze the structure of surfactant.