The amperometric biosensor for detection of sodium dodecyl sulfate

A Pseudomonas rathonis T-based amperometric biosensor was constructed for detection of anionic surfactants. Microorganisms contained the plasmid for surfactant degradation. The sensor was highly sensitive to sodium dodecyl sulfate (SDS) and volgonat. The lower limit of SDS detection was within a range of 0.25–0.75 mg 1−1. The measurement time did not exceed 5 min. 25 substances (hydrocarbons, polyols, alcohols, aromatic xenobiotics) were used to determine the substrate specificity. The sensor had the highest sensitivity to SDS; the responses to other detergents — volgonat, decylbenzene sulfonate, metaupon, toluene sulfonate and alkylbenzene sulfonate — were 82, 36, 20, 10 and 10% of response to SDS, respectively. The sensor also reacted to ethanol (56% of response to SDS), glucose (6% of response to SDS) and acetate (28% of response to SDS). The optimal laboratory conditions for SDS detection are 30 mM phosphate buffer, pH 7.5, temperature 20 °C.