Solid-phase reagents for the determination of anionic surfactants in water

Abstract

Sorption-spectrometric methods for the determination of anionic surfactants (A Surf) in natural and waste water using silica gel (SG) loaded with ion-pair associates of high molecular weight quaternary ammonium salts (QAS) and anionic dyes were developed. For this purpose, the interaction of Methyl Orange (MO), sodium picrate (Picr) and fluorescein (Fl) with didecylaminoethyl-btridecylammonium iodide (I) and N-methyl-N,N,NA,NA,NApentadecylethyldiammonium diiodide (II) immobilized on the surface of SG was investigated. SG loaded with I-MO and I-Fl associates was used for the determination of sodium dodecyl sulfate (SDS) in natural and waste water using absorbance, diffuse reflectance spectrometric and luminescence methods. Detection limits were 0.05 and 0.01 ppm, respectively. Humic and fulvic acids at levels < 0.5 ppm did not interfere with SDS determination. Water with higher acid contents was analysed using SG modified with the II-Picr associate at pH 2. Visual test scales for SDS determination in water at one fifth of the maximum admissible concentration (MAC) level was prepared.

Sublethal effects of industrial chemicals on fish fingerlings (Tilapia guineensis)

“…The surfactant levels (LAS) in 100 ml of the fish extracts, test solutions and standards (0.25, 0.5, 1.0 and 2.0 mg/l) were determined using methylene blue method (APHA, 1995;Zaporozhets et al, 1998). The method comprised of 3 successive extractions of the solutions (extracts, test solutions and standards) to which 25 ml methylene blue reagent and 10 ml chloroform have been added.…”

“…The intensity of the blue colour in the chloroform layer is proportional to the amount of LAS present. The concentrations of surfactant in the samples were then extrapolated from the calibration graph (APHA, 1995;Zaporozhets et al, 1998).…”

“…The extracts were evaporated to dryness in the extraction vessels and the dry residues were dissolved with 100 ml of warm deionised water in a water bath (Knepper et al, 1999). The redissolved solutions containing extract of the fish organs and muscle tissues were used to determine the surfactants levels following the procedure described in APHA (1995) and Zaporozhets et al (1998).…”

Interaction between Sulfonephthalein Dyes and Chitosan in Aqueous Solution and Its Application to the Determination of Surfactants

“…These methods are unsuitable for the determination of trace amounts of surfactants because of low sensitivities. On the other hand, spectrophotometry after the preconcentration of the ion associate of ionic surfactants with dye ions on a flexible polyurethane foam, 13,14 a polyvinyl chloride sheet, 15 an organic solvent-soluble membrane filter, 16 the wall of a PTFE vessel 17,18 and a filter-paper impregnated with a mixed aluminum-zinc hydroxide, 19,20 silica gel loaded with ion-pair associates of high molecular weight quaternary ammonium salts and anionic dyes, 21 have been proposed for the determination of trace amounts of surfactants.…”

“…These methods are unsuitable for the determination of trace amounts of surfactants because of low sensitivities. On the other hand, spectrophotometry after the preconcentration of the ion associate of ionic surfactants with dye ions on a flexible polyurethane foam, 13,14 a polyvinyl chloride sheet, 15 an organic solvent-soluble membrane filter, 16 the wall of a PTFE vessel 17,18 and a filter-paper impregnated with a mixed aluminum-zinc hydroxide, 19,20 silica gel loaded with ion-pair associates of high molecular weight quaternary ammonium salts and anionic dyes, 21 have been proposed for the determination of trace amounts of surfactants.The natural polymer chitin has recently been used for preconcentration 22 and determination by the spectrophotometric, 23,24 and atomic absorption spectrometric methods 25,26 of some metal ions. Trace amounts of ruthenium 27 and indium 28 in aqueous solutions were determined by incorporating their metallic elements into a precipitate of chitosan solution in acetic acid from an alkali solution, followed by atomic absorption spectrophotometry.…”