正相高效液相色谱法分析壬基环己醇聚氧乙烯醚中残留壬基环己醇

壬基环己醇聚氧乙烯醚(NCEO_n)是非环境友好型壬基酚聚氧乙烯醚(NPEO_n)潜在的升级换代产品。 本文采用正相高效液相色谱法(NP HPLC)测定产品中残存壬基环己醇(NC),用Weilbull法测定其中聚乙二醇(PEG)含量,用电喷雾电离质谱法评价聚氧乙烯(PEO)多分散指数(PDI),以此鉴定NCEO_n的品质。 为了建立快速分析NCEO_n产品中NC含量的方法,以满足跟踪检测的需求,本文筛选了反相HPLC和NP HPLC两类5种方法,并进行比较和初步条件优化,确定了用Inertsil NH₂色谱柱和示差折光检测器以及乙酸乙酯为洗脱液的NP HPLC法定量分析NC,方法的回收率为91.77%～107.6%,相对标准偏差为4.46%,最低检测限为9.8 μg/mL。 经测定,NCEO₇和NCEO₉产品中NC的残留量分别为0.158%和0.139%,PEG质量分数为7.1%和7.3%,PDI为85.0%和88.6%,证实NCEO_n产品具有NC残留量少、PEG含量低和产品PEO窄分布特征,具有在化妆品或个人洗护用品等民用产品中替代NPEO_n的潜能。

Quantitative Analysis of Residual Nonylcyclohexanol in Nonylcyclohexanol Polyoxyethylene Ethers by Normal Phase High Performance Liquid Chromatography

Nonylcyclohexanol polyoxyethylene ethers (NCEO_n) are novel potential upgraded products for replacing the non-eco-friendly nonylphenol polyoxyethylene ethers (NPEO_n). The product qualities of NCEO_n were determined revolving the residual nonylcyclohexanol (NC) by normal phase high performance liquid chromatography (NP HPLC), the polyethylene glycol (PEG) content by Weilbull procedure and the polydispersity index (PDI) by electrospray ionization mass spectrometry (ESI MS) technique. An NP HPLC program was finally proposed for rapidly determining the residual NC in NCEO_n by combining an Inertsil NH₂ column, a refractive index detector with the eluent of ethyl acetate on the basis of five preliminary experiments of NP HPLC and reversed phase HPLC. This setup achieves a recovery of 91.77%~107.6%, a relative standard deviation (RSD) of 1.59%~4.46% and a limit of detection (LOD) 9.8 μg/mL. NCEO₇ and NCEO₉ contain 0.158% and 0.139% of NC, and 7.1% and 7.3% of PEG, respectively, which indicates that the NCEO_n products have good qualities with a low NC residue, a low PEG content and a narrow distribution characteristic. Therefore, NCEO_n is a potential substitute of NPEO_n used in daily chemicals such as cosmetics, personal care products and toiletries.