2-4-dinitrophenylhydrazine and cyclohexanone

A simple and rapid method has been reported for the determination of carbonyl compounds involving reaction with 2,4-dinitrophenylhydrazine and extraction of hydrazones with water-miscible organic solvent acetonitrile when the phase separation occurs by addition of ammonium sulphate, a process called salt-assisted liquid-liquid microextraction. The extract was analyzed by high-performance liquid chromatography with UV detection at 360 nm. The procedure has been optimized with respect to solvent suitable for extraction, salt for phase separation between water and organic solvent, reaction temperature and reaction time. The method has been validated when a linear dynamic range was obtained between the amount of analyte and peak area of hydrazones in the range 7 microg-15 mg L(-1), the correlation coefficient over 0.9964-0.9991, and the limit of detection in the range 0.58-3.2 microg L(-1). Spiked water samples have been analyzed with adequate accuracy, and application of the method has been demonstrated in the analysis of benzaldehyde formed as oxidation product in pharmaceutical preparation where benzyl alcohol is used as preservative, and for a keto drug dexketoprofen.

Topics: Aldehydes; Benzaldehydes; Chemical Fractionation; Chromatography, High Pressure Liquid; Cyclohexanones; Fresh Water; Ketones; Ketoprofen; Molecular Structure; Organic Chemicals; Pharmaceutical Preparations; Phenylhydrazines; Reproducibility of Results; Solvents; Tromethamine; Water; Water Pollutants, Chemical

A new method for the determination of 2-[(dimethylamino)methyl]cyclohexanone (DAMC) in Tramadol (as active substance or active ingredient in pharmaceutical formulations) is described. The method is based on the derivatisation of 2-[(dimethylamino)methyl]cyclohexanone with 2,4-dinitrophenylhydrazine (2,4-DNPH) in acidic conditions followed by a reversed-phase liquid chromatographic separation with UV detection. The method is simple, selective, quantitative and allows the determination of 2-[(dimethylamino)methyl]cyclohexanone at the low ppm level. The proposed method was validated with respect to selectivity, precision, linearity, accuracy and robustness.

Topics: Chromatography, High Pressure Liquid; Cyclohexanones; Dimethylamines; Drug Contamination; Phenylhydrazines; Tramadol

The 2,4-dinitrophenylhydrazine (2,4-DNPH) derivatization method mainly used for the determination of airborne formaldehyde was extended for acetaldehyde, acetone, 2-butanone, and cyclohexanone, the next four carbonyl compounds of industrial importance. Sampling devices and sampling conditions were adjusted for the respective limit value regulations. Analytical reliability criteria were established and compared to those of other recommended methods. With a minimum analytical range from one tenth to the 3-fold limit value in all cases and with relative standard deviations below 5%, the adjusted method meets all requirements for the reliable quantification of the four compounds in workplace air as well as in ambient air.

Topics: Acetaldehyde; Air Pollutants; Butanones; Calibration; Chromatography, High Pressure Liquid; Cyclohexanones; Phenylhydrazines; Reproducibility of Results; Sensitivity and Specificity