A simple screening method for isolation and determination of the total content of some sulfonamides in
milk using solid-phase extraction and a color reaction is described. This procedure is based on SPE of
sulfonamides on hypercrosslinked polystyrene, elution with acetonitrile and off-line derivatization with
p-dimethylaminocinnamaldehyde in acetonitrile followed by spectrophotometric determination. The
reaction produces intense violet–red color and can be easily used both for quantitation of sulfonamides
using spectrophotometry and for naked-eye semi-quantitative estimation. Maximum absorption of the
reaction product was determined at 540 nm. The Lambert–Beer’s law was obeyed in the range of 0.07–
3.0 lg mL1 in eluate, with the squared correlation coefficient (R2
) of 0.9875–0.9995, and the relative
standard deviation (RSD) of 3–4%. The limits of SAs detection using preconcentration were of 0.02–
0.03 lg mL1
. The proposed method can be recommended as a routine screening method for quantitation
of sulfonamides in milk.