Application of low density miniaturized dispersive liquid-liquid extraction method for determination of formaldehyde in aqueous samples (water, fruit juice and streptococcus vaccine) by HPLC-UV

摘要

A simple method based on miniaturized dispersive liquid-liquid extraction is reported for extraction and preconcentration of formaldehyde in water samples. Eight milliliters of an aqueous sample containing 2,4-dinitrophenylhydrazine were added to a 10.0 mL volumetic flask containing 1.0 mL of methanol-butyl acetate (2: 1) mixture. After phase separation the analyte was determined by HPLC-UV. No clean-up or evaporation were required after extraction. Several factors influencing the extraction efficiency, such as the type and volume of organic solvent, type and volume of co-solvent, pH of the sample solution, ionic strength, and extraction time were evaluated and optimized. Under optimal experimental conditions, good linearity was obtained in the range of 1.5 x 10(-4)-10 A mu g/mL (r = 0.996), and the limit of detection was 5 x 10(-5) A mu g/mL. The method produced 20-fold enrichment of the formaldehyde. The average recovery of spiked formaldehyde in real samples was in the range of 90-110% with RSD in the range of 3-8%.