用Cadion-CPB光度法测定水中痕量阴离子表面活性剂

Determination of Anionic Surfactants in Water by Spectrometry with 1_(4_Nitrophenyl)_3 _(4 _phenylazophenyl)triazene and Cetylpyridinium Bromide

研究了用于直接测定水相中痕量阴离子表面活性剂的新体系。在ＮａＯＨ介质中，１－（４－硝基苯基）－３－［４－（苯基偶氮）苯基］－三氮烯（Ｃａｄｉｏｎ）与溴化十六烷基吡啶（ＣＰＢ）形成离子缔合物（Ｃａｄｉｏｎ－ＣＰＢ），当加入阴离子表面活性剂（ＡＳ）时，ＡＳ能定量置换出离子缔合物中的Ｃａｄｉｏｎ，而使吸光度下降。阴离子表面活性剂十二烷基苯磺酸钠（ＤＢＯＳＯ３Ｎａ）、十二烷基磺酸钠（ＤＯＳＯ３Ｎａ）、十二烷基硫酸钠（ＤＳＯ４Ｎａ）的表观摩尔吸光系数εｍａｘ分别为２．７４×１０４、１．１１×１０４、１．５０×１０４Ｌ·ｍｏｌ－１·ｃｍ－１，服从比尔定律的范围分别为０～４．１８、０～６．５４、０～５．７７ｍｇ·Ｌ－１。方法操作简便，用于测定合成水样及环境水样中痕量阴离子表面活性剂，结果满意。

A spectrometric method has been developed for the determination of anionic surfactants(AS) based on the formation of ion _ association complexes of 1_(4 _ nitrophenyl)_ 3 _(4 _ phenylazophenyl) triazene(Cadion) and cetylpyridinium bromide in the presence of NaOH. Cadion in the ion _ association complex is replaced quantitatively by AS. The apparent molar absorptivities of sodium dodecyl benzene sulfonate(DBOSO3Na),sodium dodecyl sulfonate(DOSO3Na)and sodium dodecylsulfate(DSO4Na) are 2.74×104, 1.11×104 and 1.50×104 L·mol-1·cm-1, respectively. Beer’s law is obeyed in the range of 0 ～ 4.18 mg·L-1 for DBOSO3Na, 0 ～ 6.54 mg·L-1 for DOSO3Na and 0 ～ 5.77 mg·L-1 for DSO4Na. The method has been applied to direct determination of anionic surfactants in river water with satisfactory results.