High-performance liquid chromatography of methanol released from pectins after its oxidation to formaldehyde and condensation with 2,4-dinitrophenylhydrazine.
A procedure was developed to measure the content of methanol in pectins after the base-catalysed hydrolysis of galacturonic acid methyl esters and oxidation of released methanol with potassium permanganate followed by condensation of the resulting formaldehyde (HCHO) with 2,4-dinitrophenylhydrazine (DNPH) dissolved in acetonitrile. The constant yields of resultant formaldehyde 2,4-dinitrophenylhydrazone (HCHO-DNPH derivative) were obtained at molar ratios of DNPH/HCHO higher than 5. The separation of the HCHO-DNPH derivative from DNPH reagent was achieved by isocratic reversed-phase HPLC equipped with the spectrophotometric detector set at a wavelength of 351 nm. The calibration curve was linear in the methanol concentration range between 0.04 and 15 micromol/ml (R=0.9995). The total recovery from pectin solutions spiked with methanol was equal to 100.6+/-5.1%.
Zegota
H
H
Institute of Applied Radiation Chemistry, Technical University, Lodz, Poland. ahzegota@mitr.p.lodz.pl
D000097:Acetonitriles; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D005557:Formaldehyde / Q000737:chemistry*; D007202:Indicators and Reagents; D000432:Methanol / Q000032:analysis* / Q000737:chemistry*; D010084:Oxidation-Reduction; D010368:Pectins / Q000737:chemistry*; D010659:Phenylhydrazines / Q000737:chemistry*; D015203:Reproducibility of Results
D000097:Acetonitriles; D007202:Indicators and Reagents; D010659:Phenylhydrazines; D005557:Formaldehyde; C004787:2,4-dinitrophenylhydrazine; D010368:Pectins; D000432:Methanol; C032159:acetonitrile