Equol determination in cattle manure by HPTLC-DART-TOF-MS

Abstract

We present a planar chromatographic separation method for the phytoestrogenic active compound equol, separated on silica gel High Performance Thin Layer-plates (HPTLC-plates, Merck, 1.00934). It could be shown that an ethanolic cattle manure extract contains this phytoestrogenic active compound to a larger amount. As solvents for the mobile phase have been used methyl t-butyl ether and cyclohexane (1 + 1, v/v). After separation the plate was scanned with a very specific working TOF-DART-MS system (Time Of Flight – Direct Analysis in Real Time – Mass Spectrometry) using the (M + 1)⁺-signal of equol. The detection in combination with an HPTLC-separation allows very specific detecting of equol in cattle manure, although that is a very challenging matrix. Preliminary results show that the content of equol in liquid manure is about 70 µg/g.

GRAPHICAL ABSTRACT

KEYWORDS:

• DART-TOF-MS
• equol in cattle manure
• HPTLC
• phytoestrogen equol
• TLC

Acknowledgement

The authors express their appreciation to Merck-Company (Darmstadt, Germany), and BioStep (Burkhardtsdorf, Germany) for their kind support, as well as JEOL GmbH, (Freising, Germany) for supporting HPTLC-DART/TOF spectra recording.