Congratulation on passing the PhD defence to Dr. Mengle Wang!

With her thesis on "Analysis of vitamin B12 in foods: Development and application of stable isotope dilution assays for naturally occurring cobalamins" Dr. Wang highly contributed to the complex topic of B12 analytics which is proven to be quite difficult due to low concentrations of the single vitamers in food. Also, cobalamins are prone to degradation when exposed to heat or light, so they need to be handled with special caution.

By biotechnological preparation of 15-N labelled compounds in Propionibakterium Freudenreichii standards for a sensitive and selective LC-MS method were available, enabling the detection of single vitamers in very low concentrations in food. Thus, the thesis gave new insights in the B12 composition of different food stuffs and also provides updated values of the total B12 content.

Heartfelt congratulations for this immense achievement awarded with "summa cum laude".