Optimization of solvent bar microextraction combined with gas chromatography for the analysis of aliphatic amines in water samples

Abstract

Solvent bar microextraction (SBME) combined with gas chromatography-flame ionization detector (GC-FID), was used for preconcentration and determination of some aliphatic amines in waste water samples. The effect of different variables on the extraction efficiency was studied simultaneously using an experimental design. The variables of interest in the SBME were ionic strength, organic additive effect, sodium hydroxide concentration, stirring rate and extraction time and temperature. A Plackett-Burman design was performed for screening in order to determine the significant variables affecting the extraction efficiency. Then, the significant factors were optimized by a Box-Behnken design (BBD) and the response surface equations were derived. The optimum experimental conditions were sodium chloride concentration, 20% (w/v); sodium hydroxide concentration, 1 mol L(-1); stirring rate, 700 rpm; extraction temperature, 45 degrees C; extraction time, 30 min, and without addition of acetone. Under the optimum conditions, the preconcentration factors were between 260 and 1130. The limit of detections (LODs) ranged from 0.01 microg L(-1) (for dibutylamine) to 0.06 microg L(-1) (for N-ethyldiisopropylamine). The linear dynamic ranges (LDRs) of 0.05-800 and 0.1-600 microg L(-1) were obtained for most of the analytes. The performance of the method was evaluated for extraction and determination of aliphatic amines in waste water samples in the range of microgram per liter and satisfactory results were obtained (RSDs<13.6%).