Mass spectrometry and clinical chemistry

Mass Spectrometry in the Clinical Laboratory

“…Referenced publications will primarily span 15 yr. Some older, historically important or frequently cited papers will also be included, especially for applications using GC/MS. The clinical applications of MS will be arranged in three basic groups: small metabolites such as organic acids, amino acids, fatty acids, steroids and their conjugates; peptides, proteins, and glycoproteins; , and oligonucleotides derived from biopolymers (DNA, RNA).…”

Quantitative Determination of Free and Protein‐Associated 3‐Nitrotyrosine and S ‐Nitrosothiols in the Circulation by Mass Spectrometry and Other Methodologies: A Critical Review and Discussion from the Analytical and Review Point of View

“…Thus, for the quantification of endogenous S-nitrosothiols and 3-nitrotyrosine, the respective stable-isotope-labeled analogue, such as S- (Tsikas et al, 1999b) Schwedhelm et al, 1998), is added to the respective biological matrix, such as plasma, at a relevant final concentration. Endogenous compound and internal standard undergo all chemical and physical changes during the whole analytical process, namely derivatization, extraction, and chromatographic separation (Hill and Whelan, 1984;Schoeller, 1986;Duncan, 2003). However, ions derived from derivatives of endogenous substances and their respective stable-isotope-labeled analogues are separated in the mass spectrometer due to their distinctly different mass-to-charge ratios (m/z) (Hill and Whelan, 1984; see also Section 11.2.3).…”

“…Endogenous compound and internal standard undergo all chemical and physical changes during the whole analytical process, namely derivatization, extraction, and chromatographic separation (Hill and Whelan, 1984;Schoeller, 1986;Duncan, 2003). However, ions derived from derivatives of endogenous substances and their respective stable-isotope-labeled analogues are separated in the mass spectrometer due to their distinctly different mass-to-charge ratios (m/z) (Hill and Whelan, 1984; see also Section 11.2.3). MS analysis reveals GC peaks of which the ratio of the areas or heights corresponds to the ratio of the concentrations in the biological sample.…”

“…MS analysis reveals GC peaks of which the ratio of the areas or heights corresponds to the ratio of the concentrations in the biological sample. Thus the concentration of an endogenous substance in the biological matrix is simply determined by multiplying the peak area ratio or peak height ratio measured by the known concentration of the internal standard externally added (Hill and Whelan, 1984;Schoeller, 1986). Generally, use of stable-isotope-labeled analogues as internal standards in MS-based methods generates linear standard curves within a large concentration range of several orders of magnitude (Schoeller, 1986).…”

Applications to Analytic Chemistry: An Evaluation of Stable Isotopes in Mass Spectral Drug Assays

“…and Vx is the molar volume of X. Plots of EAB(VX) 1 versus various values of O at a constant 0x value of 9.5 (approximate 0x value of methylene chloride) and 15A values of either 23.4 (the 0 value of H20) or 21.1 (a 0 value 10% less than the value for H20) are given in Figure 2. The curves are inverted parabolas.…”