Quantification of acetylcholine, choline, betaine, and dimethylglycine in human plasma and urine using stable-isotope dilution ultra performance liquid chromatography–tandem mass spectrometrySusanne H. Kirsch, Rima Obeid, Wolfgang Herrmann et al.|Journal of Chromatography B|2010Cited by 102
Concentrations of unmetabolized folic acid and primary folate forms in pregnant women at delivery and in umbilical cord bloodRima Obeid, Wolfgang Herrmann, Mariz Kasoha et al.|American Journal of Clinical Nutrition|2010Cited by 89
Quantification of key folate forms in serum using stable-isotope dilution ultra performance liquid chromatography–tandem mass spectrometrySusanne H. Kirsch, Rima Obeid, Jean-Pierre Knapp et al.|Journal of Chromatography B|2009Cited by 65
Simultaneous quantification of S-adenosyl methionine and S-adenosyl homocysteine in human plasma by stable-isotope dilution ultra performance liquid chromatography tandem mass spectrometrySusanne H. Kirsch, Rima Obeid, Jean-Pierre Knapp et al.|Journal of Chromatography B|2009Cited by 61
Concentrations of unmetabolized folic acid and primary folate forms in plasma after folic acid treatment in older adultsRima Obeid, Wolfgang Herrmann, Susanne H. Kirsch et al.|Metabolism|2010Cited by 46