title: The association effect of quaternary ammonium salt on carboxymethyl cellulose and its analytical applications.
abstract: Sodium carboxymethyl cellulose (CMC) has been extensively used in petroleum, geology, common household chemicals, food, medicine and other industries, owing to its excellent water-soluble, emulsifying, water retention and film forming properties. It is known as 'industrial monosodium glutamate'. However, the research of the test method on CMC is far behind the research of its actual application value. This study showed that, weak acid or weak basic medium, the carboxyl groups dissociated from CMC, existing as a big negative ion, which can form ion-association complexes with some quaternary ammonium cations through electrostatic and hydrophobic interactions. The absorption spectrum changes and Triton-X100 can increase the sensitivity of the system. The maximum absorption wavelengths are, respectively, about 256 nm for dodecyl trimethyl ammonium bromide (LTAB), 244 nm for tetradecyltrimethyl ammonium bromide (TTAB) and 240 nm for cetyltrimethyl ammonium bromide (CTAB) with CMC. The reactions show very high sensitivities and the maximum molar absorption coefficients are 1.10 × 10(4) L/(mol·cm) for LTAB system, 1.24 × 10(6) L/(mol·cm) for TTAB system and 1.78 × 10(6) L/(mol·cm) for CTAB system. This method is simple and rapid, and can be applied for the spectrophotometric determination of trace CMC in the supernatant of centrifuged drilling mud.
authors.affiliation: Key Laboratory of Environmental Protection & Pollution and Remediation of Water and Soil of Shaanxi Province, School of Environmental Science and Engineering, Chang'an University, Yanta Road 126, Yanta District, Xi'an City 710054, Shaanxi Province, China E-mail: ysk110@126.com.
authors.forename: Yanhua
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Key Laboratory of Environmental Protection & Pollution and Remediation of Water and Soil of Shaanxi Province, School of Environmental Science and Engineering, Chang'an University, Yanta Road 126, Yanta District, Xi'an City 710054, Shaanxi Province, China E-mail: ysk110@126.com.
authors.forename: Chanjuan
authors.initials: C
authors.lastname: Gao
authors.affiliation: Key Laboratory of Environmental Protection & Pollution and Remediation of Water and Soil of Shaanxi Province, School of Environmental Science and Engineering, Chang'an University, Yanta Road 126, Yanta District, Xi'an City 710054, Shaanxi Province, China E-mail: ysk110@126.com.
authors.forename: Shengke
authors.initials: S
authors.lastname: Yang
mesh_terms: D064751:Ammonium Compounds / Q000737:chemistry*; D002266:Carboxymethylcellulose Sodium / Q000737:chemistry*; D057927:Hydrophobic and Hydrophilic Interactions; D013053:Spectrophotometry / Q000379:methods; D055672:Static Electricity; D014867:Water / Q000737:chemistry*
chemical_list: D064751:Ammonium Compounds; D014867:Water; D002266:Carboxymethylcellulose Sodium