Aim. Lactulose/mannitol ratio is used to assess intestinal barrier function. Aim of this work was to develop a robust and rapid method for the analysis of lactulose and mannitol in urine by liquid chromatography coupled to tandem mass spectrometry. Lactulose/mannitol ratio has been measured in pediatric patients suffering from irritable bowel syndrome. Methods. Calibration curves and raffinose, used as internal standard, were prepared in water : acetonitrile 20:80. Fifty mu L of urine sample was added to 450 mu L of internal standard solution. The chromatographic separation was performed using a Luna NH2 column operating at a flow rate of 200 mu L/min and eluted with a linear gradient from 20% to 80% water in acetonitrile. Total run time is 9 minutes. The mass spectrometry operates in electrospray negative mode. Method was fully validated according to European Medicine Agency guidelines. Results and Conclusions. Linearity ranged from 10 to 1000 mg/L for mannitol and 2.5 to 1000 mg/L for lactulose. Imprecision in intra-and interassay was lower than 15% for both analytes. Accuracy was higher than 85%. Lactulose/mannitol ratio in pediatric patients is significantly higher than that measured in controls. The presented method, rapid and sensitive, is suitable in a clinical laboratory.
Lelental, N., Brandner, S., Kofanova, O., Blennow, K., Zetterberg, H., Andreasson, U., Engelborghs, S., Mroczko, B., Gabryelewicz, T., Teunissen, C., Mollenhauer, B., Parnetti, L., Chiasserini, D., Molinuevo, J. L., Perret Liaudet, A., Verbeek, M. M., Andreasen, N., Brosseron, F., Bahl, J. M. C., Herukka, S. K., Hausner, L., Frölich, L., Labonte, A., Poirier, J., Miller, A. M., Zilka, N., Kovacech, B., Urbani, A., Suardi, S., Oliveira, C., Baldeiras, I., Dubois, B., Rot, U., Lehmann, S., Skinningsrud, A., Betsou, F., Wiltfang, J., Gkatzima, O., Winblad, B., Buchfelder, M., Kornhuber, J., Lewczuk, P., Comparison of Different Matrices as Potential Quality Control Samples for Neurochemical Dementia Diagnostics, <<JOURNAL OF ALZHEIMER'S DISEASE>>, 2016; 52 (1): 51-64. [doi:10.3233/JAD-150883] [http://hdl.handle.net/10807/94470]
Comparison of Different Matrices as Potential Quality Control Samples for Neurochemical Dementia Diagnostics
Urbani, Andrea;
2016
Abstract
Aim. Lactulose/mannitol ratio is used to assess intestinal barrier function. Aim of this work was to develop a robust and rapid method for the analysis of lactulose and mannitol in urine by liquid chromatography coupled to tandem mass spectrometry. Lactulose/mannitol ratio has been measured in pediatric patients suffering from irritable bowel syndrome. Methods. Calibration curves and raffinose, used as internal standard, were prepared in water : acetonitrile 20:80. Fifty mu L of urine sample was added to 450 mu L of internal standard solution. The chromatographic separation was performed using a Luna NH2 column operating at a flow rate of 200 mu L/min and eluted with a linear gradient from 20% to 80% water in acetonitrile. Total run time is 9 minutes. The mass spectrometry operates in electrospray negative mode. Method was fully validated according to European Medicine Agency guidelines. Results and Conclusions. Linearity ranged from 10 to 1000 mg/L for mannitol and 2.5 to 1000 mg/L for lactulose. Imprecision in intra-and interassay was lower than 15% for both analytes. Accuracy was higher than 85%. Lactulose/mannitol ratio in pediatric patients is significantly higher than that measured in controls. The presented method, rapid and sensitive, is suitable in a clinical laboratory.
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