Glyoxal and methylglyoxal determination in urine by surfactant-assisted dispersive liquid-liquid microextraction and LC

Aim: Two important markers of oxidative stress, glyoxal and methylglyoxal, are preconcentrated from human urine by surfactant-assisted dispersive liquid-liquid microextraction and separated by LC-fluorescence. Methods/results: Derivatization was carried out overnight with 0.8 mM 2,3-diaminonaphthalene at 4 degrees C. For surfactant-assisted dispersive liquid-liquid microextraction, 500 mu l buffer solution (pH 10.5) and 25 mu l 0.03 M Triton X-114 were added to 2.5 ml of the sample and the mixture was made up to 10 ml before the rapid injection of 75 mu l 1-undecanol (extractant solvent) and 0.5 ml ethanol (dispersant solvent). Conclusion: The method can be applied to analyze glyoxal and methylglyoxal in urine with LOD of 13 and 16 ng/l, respectively, and recoveries in the 88-103% range.