Extraction of acetaldehyde from mineral water using 2,4- dinitrophenylhydrazine as derivatizing agent

Resumo

Acetaldehyde generated, when PET bottles of water are deposited at high temperature for long period of time. The acetaldehyde produced, transferred into the mineral water and alter the organoleptic properties of water. Acetaldehyde is also a possible carcinogen and mutagen. In the present research work, acetaldehyde in mineral water was derivatized with 2, 4-dinitrophenyl hydrazine (DNPH), extracted by solid phase extraction (SPE) using octadecyl silane oxide (C18) and finally investigated by gas chromatography (GC). Acetaldehyde-2, 4-dinitropheyl hydrazone (A-DNPH) formed after derivatization which were adsorbed on the surface of C18. Solvent acetonitrile was used for the elution of A-DNPH from the solid phase extraction (SPE) column. Effect of storage time and light on the migration of acetaldehyde was investigated and found the mineral water stored for longer period of time in sun light change their organoleptic properties due to migration of acetaldehyde into water.  Detection limit of this method was 9.8µg/L while the efficiency of the method was 87.6%, which was higher than solid phase micro-extraction. The concentration of acetaldehyde determined by this method was in the range of 9.8 to 61 µg/L. The results indicate that C18 packed in column had good efficiency to hold the acetaldehyde-DNPH, hence it is good adsorbent for acetaldehyde extraction from bottled mineral water. Thus, it has been concluded that bottled water should not be stored at elevated temperature for longer period of time. High temperature and long storage duration increase the acetaldehyde concentration in bottled water which changes the organoleptic properties of water.  Water with acetaldehyde concentration greater than 20 g/L have changed organoleptic properties but is acceptable for consumption.

Key words: Acetaldehyde, Octadecyl silane oxide, Acetonitrile, Poly (ethylene terephthalate), Gas chromatography