Premium
A method for the detection and estimation of trace levels of theobromine in mixed horse feed
Author(s) -
Taylor Philip W.
Publication year - 1982
Publication title -
journal of the science of food and agriculture
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.782
H-Index - 142
eISSN - 1097-0010
pISSN - 0022-5142
DOI - 10.1002/jsfa.2740330615
Subject(s) - theobromine , chromatography , chemistry , elution , distilled water , acetone , chloroform , reagent , residue (chemistry) , detection limit , theophylline , biochemistry , biology , endocrinology
A method for the detection and estimation of theobromine in compounded horse feed by high‐performance liquid chromatography (h.p.l.c.) is presented. The sample is extracted by refluxing with distilled water and clarified by the addition of Carrez reagents. The level of co‐extractives is reduced by precipitation by the addition of 4 vols of acetone, and a measured volume of the filtrate transferred on to a silica column for clean‐up. The theobromine is eluted with chloroform (85%)‐propan‐2‐ol (15%) and the eluate evaporated to dryness. The residue is dissolved in water and analysed by h.p.l.c. (using a reverse‐phase column and ultraviolet detection at 272 nm). The method has been tested on mixed horse feeds and their ingredients. Theobromine recoveries were in the range 78–86% and concentrations down to 2 mg kg −1 could be measured. Three ways to confirm positive results are presented.