Determination of serum urea by isotope dilution mass spectrometry as a candidate definitive method

Isotachophoretic Determination of Urea-Ammonium in Plasma: A Candidate Reference Method

“…Depending on accuracy, precision and specificity, the classical analytical methods were often proposed as definitive methods (e. g. isotope dilution mass spectrometry) and reference methods (e.g. GC and HPLC) in clinical chemistry (12,13,14,15). The definition and the analytical procedure of a reference method and the reference materials in clinical chemistry were comprehensively documented by Stamm (16,17) and Tietz (18).…”

IFCC Sections/IFCC-Sektionen

“…The reqüirement of the internal calibration material is that its recovery during the Isolation procedure should be identical to that of the analyte and that it should not be differentiated from the analyte until the final de* tection stage. Each analogue will have to be tested in this respect (46,50,51). In favourable instances, precision may also improve but shorMerm variations in mass spectrometry sensitivity may introduce random or systematic error (31).…”

“…Examples of this approach have been reported in the literature(10,46,48,49,50,51). Examples of this approach have been reported in the literature(10,46,48,49,50,51).…”

Developing a reference measurement procedure for free glycerol in human serum by two-step gas chromatography–isotope dilution mass spectrometry

“…Isotope dilution mass spectrometry (IDMS) is recognized to be a primary method [16][17][18], which has been widely used to establish reference measurement procedures for organic biomarkers such as creatinine [19][20][21], glucose [22][23][24], cholesterol [25][26][27], urea [28,29], uric acid [30,31] and triglycerides [32,33]. A GC-IDMS method for free glycerol measurement was reported previously [13].…”