Solid phase preconcentration-Fourier transform infrared spectrometric determination of carbaryl and 1-naphthol

An analytical procedure has been developed for the simultaneous determination of carbaryl and 1-naphthol in water samples by means of in-field sampling and preconcentration on C18 solid phase cartridges which, after drying are eluted on-line with a carrier flow of chloroform; carbaryl and 1-naphthol are determined by Fourier transform infrared spectrometry. Carbaryl is determined directly from the peak area of the flow injection absorbance versus time recordings, measured at 1741 cm−1 with a baseline correction established at 1875 cm−1. For 1-naphthol the peak area values were measured from the first order derivative peak, obtained between the peak at 1280 cm−1 and the valley at 1272 cm−1 which correspond to the derivative spectrum of the absorbance band at 1276 cm−1. Measurements carried out by batch elution of the preconcentrated solutions provided detection limits of 0.36 mg l−1 for carbaryl and 1.6 mg l−1 for 1-naphthol for a sample volume of 100 ml.