Comparison of different techniques used in UHPLC-MS/MS to quantify a standardized Dry Grape Extract in complete feeds

The use of botanicals in animal nutrition is increasing rapidly. Their use requires the development of quantification methods to control the level of supplementation, homogeneity and stability in complete feeds. These regulatory and control requirements require methods that can be used routinely.

The use of botanicals is however a real challenge for quantification as they are mainly ingredients consisting of hundreds of molecules with incorporation thresholds in the ppm range. A representative molecule of the mixture called a phytomarker is often used for the quantification.

As the response thresholds are low, chromatography coupled to mass spectrometry associated with an adapted sample preparation is usually used for quantification. These methods are accompanied by a set of phenomena that can affect the accuracy of the quantification: loss of the analyte during extraction, mass ionisation and matrix effects.

The objective of this study was to compare several techniques used in UHPLC-MS/MS in order to quantify a standardized Dry Grape Extract in complete feed (Nor-Grape​, Nor-Feed, France) at 30 ppm by following the phytomarker malvidin-3-O-glucoside.

External calibration, mismatched calibration, standard addition and internal standard techniques were tested to determine which one would be both accurate and suitable for routine use.

The results showed that the use of a double standard addition with an internal standard provides high accuracy for the quantification and saves considerable time on sample preparation. This makes it a suitable technique for routine control but needs interlaboratory validation to be fully validated.

 

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Publication History

Article published online:
16 November 2023