Chromatography Forum

I am looking for information regarding sample prep using waters DNPH SPE cartridges. I am currently trying to extract wines (both red and white) to look for any aldehydes/ketones that may be present. I need sample prep as well as column/ run time information for HPLC if at all possible. I am using an HP 1050 with an ultra aqueous C18 5uM column (250x4.6mm).

Thanks!

With respect to the analysis of aldehydes, you can get a lot of information from the Waters website at www.waters.com. Type DNPH into the upper right corner. If you have a Waters catalogue, there are also a bunch of chromatograms under Sep-Pak DNPH Silica cartridges.

That said, the DNPH method was originally designed for the analysis of air. You will need to think through, how you can adopt the method for a liquid. I can see how you could extract the aldehydes and ketones with a Sep-Pak method, followed by derivatization.

I kind of figured it would be an interesting/difficult procedure. Thank you for the advice, I'll check out the waters website.

I have analyzed 6 mixed DNPH-aldehyde standard solutions using HPLC and UPLC.
I used water/acetonitrile = (60:40, v/v) for dilution, which was the same as mobile phase. I also tried water for dilution. Peak shape was sharp, but peak intensity was low compared to water/acetonitrile = (60:40, v/v). If you evaporate your sample after extraction, you should not use water for reconstitution.
Good luck!
Best Regards,

You might want to look at the following recent paper, and references therein. I suspect a Literature search will also find details of suitable sample preparation.

Bruce Hamilton

Analysis of selected carbonyl oxidation products in wine by liquid chromatography with diode array detection
Analytica Chimica Acta Volume 626, Issue 1, 19 September 2008, Pages 104-110

Ryan J. Eliasa, 1, V. Felipe Laurieb, , , Susan E. Ebelera, Jon W. Wongc, 2 and Andrew L. Waterhousea

A high performance liquid chromatography (HPLC) method for the detection and quantitation of acetaldehyde, glyceraldehyde, pyruvic acid, 2-ketoglutaric acid, and formaldehyde in wine, based on the formation of the 2,4-dinitrophenylhydrazones, is presented. These carbonyl compounds often result from the chemical oxidation of major wine components, and are known to affect flavor and color stability. Their analysis in wine is complicated due to their instability and their tendency to react reversibly with bisulfite to form α-hydroxysulfonates. Published methods that break down the sulfonates for the quantitation of total carbonyls in wine involve alkaline hydrolysis of sulfite-bound carbonyls, but we show, for the first time, that this alkaline treatment step significantly increases the concentration of carbonyls during analysis. A solution based on oxygen exclusion is described. The technique offers good specificity, reproducibility (%RSD 0.45–10.6), and limits of detection (1.29–7.53 μg L−1). The method was successfully used to monitor concentration changes of these compounds in both white and red wines.

Below are applications for DNPH aldehydes and ketones separated on Cadenza CD-C18

http://www.silvertonesciences.com/files/TI020E.pdf
http://www.silvertonesciences.com/files/TI070E.pdf