3.2. Analytical performance
The optimized μ-SPE procedure conditions were as follows:
sample pH, pH 3; SDBS concentration, 90 mg L1 ; elute solvent,
methanol; extraction time, 40 min; and desorption time, 6 min.
Under these conditions, a series of working solutions containing
sulfonamides were used to establish the calibration curves.
The repeatability experiments were carried out by six parallel experiments
at the concentration of 20 μg L1 for each of the sulfonamides.
The analytical parameters are presented in Table 1. Based on
the ratio of signal to noise equal to three (S/N ¼ 3), the limits of
detection of the proposed method were in the range of in the significant enhancement of the extraction efficiencies of the
target sulfonamides. The proposed method provided good linear
ranges of 1–200 μg L1 for the six sulfonamides with the correlation
coefficients in the range of 0.998–0.999. All the results
showed that modified TiO2 nanotube arrays were a good promising
adsorbent, and the proposed method could be potentially used
as a routine analytical tool for sulfonamides.