3 dgal

For all experiments, freshly prepared ultrapure water was taken from Sartorius arium^® pro UV water treatment system (Sartorius AG, Göttingen, Germany). All chemicals were of analytical grade, unless noted otherwise. Acetonitrile, OPD, 2,3-dimethylquinoxaline, MGO, GO, 2-KDG, 3-DG, 5-HMF, D-(+)-glucose monohydrate, methanol and ammonium acetate were purchased from Sigma (Sigma-Aldrich Chemie GmbH, Steinheim, Germany). 3-DGal was obtained from Cayman (Cayman Chemical Company, Ann Arbor, MI, USA). 3,4-DGE was purchased from Carbosynth (Carbosynth Ltd., Compton, Berkshire, UK).
The aqueous phase during LC-MS/MS measurement was a 5 mM ammonium acetate buffer solution adjusted to pH = 3.5 using 0.1% (v/v) acetic acid. It was freshly prepared in accordance to Thomas et al. [54 (link)]. The EZ-Test^® [55 ] Biological Indicator from MesaLabs was used in order to test sterility.

For all experiments, freshly prepared ultrapure water was taken from the Sartorius arium® pro UV water-treatment system (Sartorius AG, Göttingen, Germany). All chemicals were of analytical grade, unless noted otherwise. Acetonitrile, OPD, 2,3-dimethylquinoxaline, MGO, GO, 2-KDG, 3-DG, 5-HMF, D-(+)-glucose, methanol, and ammonium acetate (for mass spectrometry) were purchased from Sigma (Sigma-Aldrich Chemie GmbH, Steinheim, Germany). Acetic acid (glacial) 100%, toluene, sulfuric acid 95–98%, and ethanol 96% were obtained from Merck (Merck KGaA, Darmstadt, Germany). Furthermore, 1,4-dioxane and thymol were purchased from Roth (Carl Roth GmbH & Co. KG, Karlsruhe, Germany). The 3-DGal was obtained from Cayman (Cayman Chemical Company, Ann Arbor, Michigan, USA), and 3,4-DGE was purchased from Carbosynth (Carbosynth Ltd, Compton, Berkshire, UK).
thymol-sulfuric acid reagent was freshly prepared according to the monograph "Glucose" from the Ph. Eur., section C "Thin Layer Chromatography", subitem “Detection” [21 ]:
0.5 g of thymol were solved in a mixture of 5 mL of sulfuric acid and 95 mL of ethanol 96% (v/v). No cooling was required for this step.
The aqueous phase during LC-MS/MS measurement was a 5 mM ammonium acetate buffer solution adjusted to pH = 3.5 using 0.1% (v/v) acetic acid. It was freshly prepared according to Thomas et al (2013) [22 (link)].