Assessment of energy dispersive X-ray fluorescence for rapid quantification of mineral elements in untreated cow urine

Mineral elements are key to many physiological processes in mammals. Current reference methods for mineral identification and quantification in biological samples are inductively coupled plasma mass spectrometry and inductively coupled plasma-optical emission spectrometry (ICP-OES). These analyses are costly, destructive and require trained personnel to operate. On the other hand, energy dispersive X-ray fluorescence (EDXRF) can represent a valid alternative for the rapid determination of mineral concentrations in biological matrices. This study aimed to evaluate the effectiveness of EDXRF for rapid quantification of major minerals (Na, Mg, P, S, Cl, K and Ca) in untreated urine samples, potentially reducing time and costs of the analysis. Reference concentrations were determined on 74 samples using ICP-OES. The performances of EDXRF for rapid quantification of urine mineral composition were assessed using a calibration set (100% of the samples), a training set (70%) and a testing set (30%). Rapid quantification performed by EDXRF displayed a strong correlation with reference quantification performed by ICP-OES for S and Cl, as well as a good correlation for Mg (with R 2 in testing of 0.95, 0.89 and 0.70, respectively). Results of the present study suggest that EDXRF is suitable for rapid monitoring of urinary S and Cl and for rapid screening of urinary Mg. Aligning with the growing need for decision-supporting tools for farmers and nutritionists at both individual and herd levels, such findings may help in diagnosing nutritional imbalances and tuning dairy cows’ diets.