A study on the durability of a graphitized carbon column and simultaneous determination of chloride, bromide and sulfate in color additives using Sep-Pak C_18 as a chemical filter by ion chromatography

摘要

A graphitized carbon column for ion chromatography has been used in the simultane- ous determination of inorganic anions in various samples. This paper describes an investigation on the durability of column using color additives for drugs and cosmetics (D&C colors) as an injection matrix. The effects of the matrix on the retention behav- ior were examined for 6 common anions (F~- 9 Cl~-, NO_2~-, Br~-, NO_3~- and SO_4~(2-) after 10 repeated injections of an aqueous solution of 1.0 mg ml~(-1) Acid Yellow l. The number of theoretical plates and peak areas for anions after 90 injection were in good agreement with those at initial injection, while avoiding any matrix effect. In addition, simultane- ous determination of chloride, bromide and sulfate in D&C colors was examined after a pretreatment for the selective removal of D&C colors. A Sep-Pak C18 cartridge as a chemical filter and 0.05 mM tetrabutylammonium (TBA) in a sample solvent were effec- tive to retain the D&C colors, while chloride, bromide and sulfate passed through unre- tained. The recoveries of Cl~- (7.5), Br~- (1.5) and SO_4~- (1.5 μg ml~(-1) ) added to six D&C colors (0.1 mg ml~(-1)) were 99.8 ～ 101.2, 98.3 ～ 99.7 and 95.1 ～ 97.5, respectively.