Application of membrane filters for spectrophotometric determination of cationic surfactants in river water and sediment.
Cationic surfactant (CS+) in urban river water and sediment was extracted and determined spectrophotometrically with 2 membrane filters. The CS+ in the water samples, mostly in the form of an ion associate with the coexisting anionic surfactant (AS), was collected on a polytetrafluoroethylene (PTFE) membrane filter and eluted with methanol. Bromphenol blue (BPB), hydrochloric acid, and water were added to the methanol solution successively, and the mixed solution was filtered through a mixed cellulose ester membrane filter. The CS+-BPB- ion associate, formed by a counter ion exchange, was collected on the filter and dissolved into N,N-dimethylformamide (DMF) together with the mixed cellulose ester membrane filter. After addition of 2 drops of triethanolamine, the absorbance of the DMF solution was measured. The CS+ in sediment samples was extracted with methanol by ultrasonic irradiation; the methanol solution was then passed through a PTFE membrane filter and evaporated to dryness. The CS+ was redissolved in a small amount of methanol. For water samples, recoveries and relative standard deviations for 0.30 microM benzyldimethyl-tetradecylammonium ion, a standard material, were > or =93 and < or =5%, with a detection limit of 0.02 microM. Concentrations of CS+ in sediments were much higher than those in water samples, indicating that CS+ is adsorbed on the surface of the sediment.
Huij-Feng
S
S
Toyama University, Faculty of Science, Gofuku, Japan.
Takamori
M
M
Hata
N
N
Kasahara
I
I
Taguchi
S
S
D000327:Adsorption; D002412:Cations; D005618:Fresh Water / Q000032:analysis; D019015:Geologic Sediments / Q000032:analysis*; D008851:Micropore Filters; D012995:Solubility; D012997:Solvents; D013053:Spectrophotometry / Q000379:methods; D013501:Surface-Active Agents / Q000032:analysis* / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000032:analysis*
D002412:Cations; D012997:Solvents; D013501:Surface-Active Agents; D014874:Water Pollutants, Chemical