Development of an analytical method for phenol and methylphenols in water, using SPE-columns and by on-column derivatisation
Ontwikkeling van een analysemethode voor fenol en cresolen in water middels SPE en on-column derivatisering
27 May 2012, PDF |
49 pages |
van der Velde EG, Broekman MH, van de Beek AIM, Groenemeijer GS, Zomer G
RIVM Report 771402026
This report describes the development of an analytical method for the determination of phenol and methylphenols (cresols) in water, especially in leachates. This experimental research was necessary because a standardized method was not available for these compounds in water. A special concept was developed whereby the free phenols were extracted from the water using SPE-columns, followed by on-column derivatisation of the free phenols with acetylchoride in hexane (5% v/v) using sodiumhydroxide powder and tetrabutylammonium hydrogen stofsulfaat as fase-transfer-catalist, and desorption of the phenylacetates with hexane. Analysis of the phenylacetates was preformed with GC-FID of GC-MS. Advantages are the fast and easy to automate method with an unique combination of on-column extraction and derivatisation, which avoids the need of a solvent phase switch. The method validation showed the following characteristics: no concentration dependence was found over a concentration range of 25 ug/l to 25 mg/l with a limited breakthroug, only 12% for phenol at a level of 25 mg/l. The longterm reproducibility for phenol, cresols and dimethylphenols was around 80% with a standard deviation of 2 to 6% for all matrices. The limit of determination was around 1 ug/l using GC-FID analysis. Analysis of dimethylphenols can be performed with this method as well, or they can be used as internal standards. The stability of the components is 7 days at 4 degrees C and can be increased by conservation at pH 2 of pH 12. Application of GC-MS improves the limit of determination to 0.1 ug/l for phenol and o-and m-cresol, for p-cresol this is 0.3 ug/l.