Field detection of sulfonamides in urine: The development of a new and sensitive test

A new, field-adapted, colorimetric method for detecting sulfonamide drugs in urine is described. The method uses the color reagent, p-dimethylaminocinnamaldehyde, and has a detection limit of about 1 mu g/ml. Analysis of, 35 samples collected in the field, comparing results obtained with the colorimetric field test with those obtained using high-performance liquid chromatography, indicated a calculated sensitivity value of 94% and a specificity value of 94% for the test to detect the presence of sulfonamides. The field test can be modified to allow quantitation of sulfonamides in urine in field situations, using a hand-held, portable photometer for measuring the absorbance of test solutions. For this test, calculated coefficients of variation for day to day reproducibility were less than or equal to 5% at sulfonamide concentrations greater than or equal to 3 mu g/ml. This new test for detecting the presence of sulfonamides in urine is more sensitive and reliable than the presently used Bratton-Marshall test.