Spectrophotometric Determination of Anionic Surfactants in Water with On-line Solvent Extraction

2 Spectrophotometric Determination of Anionic Surfactants in Water with On-line Solvent Extraction 

Spectrophotometric batch procedures based on the solvent extraction of an ion associate formed between an anionic surfactant and a cationic dye are often used for the determination of anionic surfactants. Such procedures are usually tedious to operate. The method described here, based on an optimized on-line solvent extraction procedure for the determination of anionic surfactants reported by Motomizu et al.[27], could demonstrate the efficiency and sensitivity which can be achieved by a FIA procedure. 

Spectrophotometer equipped with a flow-cell of 10 mm light path, 18 p volume. Wavelength 658 nm. Chart recorder or integrator readout. 

6-port sample injector as shown in Fig. 2.4. Sample loop volume, 100 or 3(X) /xl. Two double-plunger pumps or a single 4-channel peristaltic pump equipped with a displacement bottle for organic solvent delivery. 

T-tube phase segmentor and sandwich-type membrane phase separator. 300 cm long, 0.5 mm i.d. PTFE tubing extraction coil. 

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