Determination of nitrate in hop cones - comparison of two hplc and one spectrophotometric method
1996
Kac, M. (Ljubljana Univ. (Slovenia). Biotechnical Fac., Food Science and Technology Dept.) | Seliga-Rebercnik, A. (Hop Research and Brewing Inst., Zalec (Slovenia))
Nitrate content in hop cones was determined by two HPLC methods (reverse phase HPLC on APS Hypersil column with UV-VIS detection and ion chromatography on IonPac AS12A column with conductivity detection). The somewhat lower values obtained by ion chromatography (4 - 8%) can be attributed to not completely separated peak for phosphate ion. Results of these two methods have been compared with reference to spectrophotometric determinations performed by another laboratory (included in ring tests for similar samples). Preparation and purification of the extracts have been given special attention. Accuracy and reproducibility of the methods are good enough to establish a sound basis for evaluation of differences between analytical results for nitrate content in hops (and hop products) and thus for monitoring nitrate content in such and similar samples.
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