Ergot alkaloid contaminated barley. Claviceps purpurea fungi form sclerotia, which contain the ergot alkaloids in higher concentrations.
Source: BAM, division Organic Trace and Food Analysis
Mycotoxins (toxins formed by fungi) in food and have caused problems for mankind since the beginning of time. The group of ergot alkaloids plays a special role in human history. Several tens of thousands of deaths during the middle ages due to ergotism (the disease caused by continuous intake of ergot alkaloid contaminated food) underscore the importance of reliable analytical methods to ensure food safety.
More than 50 compounds belong to the group of ergot alkaloids. The 12 most found structures – the major ergot alkaloids – are typically measured, when it comes to ergot alkaloid quantification. High performance liquid chromatography (HPLC) with a fluorescence detector (FLD) is typically used to quantify the ergot alkaloid content. The main disadvantage of this method are the high costs for calibration standards (12 different calibration substances are required). But also the time and effort required for the analysis of 12 peaks and overlapping signals that occur in complex food samples such as bread.
As all ergot alkaloids share the ergoline structure and just differ in the substituents attached to this backbone, measurement of all ergot alkaloids in one sum parameter presents a time and cost saving alternative. The most important step for the development of such a sum parameter method is the reaction used to transfer all ergot alkaloids to one uniform structure. In this paper two promising reactions, the acidic esterification to lysergic acid methyl ester and hydrazinolysis to lysergic acid hydrazide, are examined for possible use in a routine analysis method. In addition to yield and reaction rate, factor such as the handling of the reaction and the possibility of parallelization play a role. While the acidic esterification proved to be unsuitable due to the susceptibility to oxidation and long reaction times, the hydrazinolysis showed convincing results including simple handling, the possibility to measure multiple samples in parallel, and a reasonable reaction time.
Cleaving Ergot Alkaloids by Hydrazinolysis - A Promising Approach for a Sum Parameter Screening Method
Maximilian Kuner, S. Kühn, H. Haase, Klas Meyer, Matthias Koch
published in Toxins, Vol. 13, S. 342 ff.
BAM, division Process Analytical Technology and division Organic Trace and Food Analysis