Application of γ-Ray Irradiation to Reduction of Blank for Highly Sensitive Analysis of Low Molecular Weight Aldehydes in Water

For a highly sensitive analysis of formaldehyde and acetaldehyde in water, a degradation of formaldehyde and acetaldehyde in blank water by 60Co γ-ray irradiation was demonstrated. Formaldehyde and acetaldehyde in water were evaluated by using a large-volume injection/column switching/high pressure gradient HPLC system coupled with 2,4-dinitrophenylhydrazine derivatization. By γ-ray irradiation, formaldehyde was decomposed to formic acid, and the resulting formic acid was furthermore decomposed. Acetaldehyde also oxidized to acetic acid upon exposure to γ-rays. In the early stage of γ-ray irradiation for Milli-Q water, the formaldehyde and acetaldehyde in Milli-Q water increased, and many unknown peaks appeared in HPLC chromatograms. The formaldehyde, acetaldehyde and unknown species formed upon γ-ray irradiation may be derived from trace organic mater contained in Milli-Q water. Acetaldehyde and unknown peaks disappeared upon further γ-ray irradiation, and the formaldehyde peak was also diminished. In this report, purification of the DNPH derivatization reagent is also mentioned.