Response surface methodology for optimization of cyanamide analysis byin situderivatization and dispersive liquid-liquid microextraction (original) (raw)

Journal of Chemometrics, 2014

Abstract

ABSTRACT Cyanamide is widely used for agricultural purposes; therefore, its residues can be found in water. A new method was developed for its quantification using in situ derivatization with 2,6-dimethyl-4-quinolinecarboxylic acid N-hydroxysuccinimide ester followed by dispersive liquid–liquid microextraction (DLLME) and high-performance liquid chromatography/fluorescence analysis. Multivariate chemometric techniques were successfully used to obtain the optimum conditions for direct derivatization and DLLME extraction. Derivatization parameters and DLLME extraction conditions were optimized by a two-step design, 2k factorial design for screening, and central composite design for optimization. Best derivatization conditions were addition of 600 μL of derivatizing reagent, a temperature of 4 ºC, and pH 8.5, whereas for optimum extraction 800 μL of solvent, 30% NaCl conc. w/v, and pH 3.8 were chosen. The analytical performance of the method for routine analysis was evaluated. Excellent linearity was achieved from 10 to 200 μgL�1 with a correlation factor of 0.9996. Precision ranged from 3.5% to 5.5% for intraday assays and 8.5% to 8.6% for interday assays. The mean recoveries performed on water from different origins (ground, river, sea, tap, and mineral) at three levels of concentration (20, 75, and 200 μgL1) ranged from 90.2% to 110.2%.

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