Mass spectrometry is an important part of multicomponent analytical systems designed for diagnosis of metabolic disorders. About 50 different

Transcription

1 Dr Mosaddegh

2

3 Mass spectrometry is an important part of multicomponent analytical systems designed for diagnosis of metabolic disorders. About 50 different diseases with increased excretion of organic acids are recognized today.

4 Carnitine, acylcarnitines and amino acids. Since carnitine is a vehicle by which the acyl groups can leave the mitochondria and there is an equilibrium between acylcarnitines and their respective CoA thioesters, the analysis of carnitine and acylcarnitines in blood is approximately equivalent to the analysis of acyl-coas in the mitochondria. The concept of acylcarnitine profile rather than urine organic acid profile was therefore indicated as a potentially more valuable diagnostic tool for the disorders of branched-chain amino acid and FA catabolism. It is a valuable tool for the diagnosis of some long-chain FA oxidation defects which are Difficult to diagnose by classical chromatographic method. The method has the potential to screen effectively for at least a dozen other disorders.

5 Mass spectrometer to determine the 16 O/ 18 O and 12 C/ 13 C isotope ratio on biogenous carbonate Main article: Isotope ratio mass spectrometry Mass spectrometry is also used to determine the isotopic composition of elements within a sample. Differences in mass among isotopes of an element are very small, and the less abundant isotopes of an element are typically very rare, so a very sensitive instrument is required. Some isotope ratios are used to determine the age of materials for example as in carbon dating.

6 Pharmacokinetics is often studied using mass spectrometry because of the complex nature of the matrix (often blood or urine) and the need for high sensitivity to observe low dose. The most common instrumentation used in this application is LC-MS with a triple quadrupole mass spectrometer. Tandem mass spectrometry is usually employed for added specificity.

7 Mass spectrometry is an important emerging method for the characterization and sequencing of proteins. One of primary methods for ionization of whole proteins are electrospray ionization (ESI).

8 Mass spectrometers were used in hospitals for respiratory gas analysis beginning around 1975 through the end of the century. Some are probably still in use but none are currently being manufactured. Found mostly in the operating room, they were a part of a complex system, in which respired gas samples from patients undergoing anesthesia were drawn into the instrument through a valve mechanism designed to sequentially connect up to 32 rooms to the mass spectrometer. A computer directed all operations of the system. The data collected from the mass spectrometer was delivered to the individual rooms for the anesthesiologist to use. The uniqueness of this magnetic sector mass spectrometer may have been the fact that a plane of detectors, each purposely positioned to collect all of the ion species expected to be in the samples, allowed the instrument to simultaneously report all of the gases respired by the patient. Although the mass range was limited to slightly over 120 u, fragmentation of some of the heavier molecules negated the need for a higher detection limit. [45]

9 Application of tandem mass spectrometry to the analysis of chlorinated compounds Lucija Zupančič-Kralj, Jože Marsel, Bogdan Kralj and Dušan Žigon The application of high-resolution gas chromatography mass spectrometry and tandem mass spectrometry (MS MS) in environmental analysis is demonstrated with three typical compound types, i.e., polychlorinated biphenyls (PCBs), polychlorinated alkanes (PCAs) and polychlorinated naphthalenes (PCNs), found in/or during the preparation of some environmental samples from a contaminated area.

10 Szulejko, J.E. McCulloch, M. Jackson, J. McKee, D.L. Walker, J.C. Solouki, T. Dept. of Chem., Univ. of Maine, Orono, ME, USA This paper appears in: Sensors Journal, IEEE Issue Date: Jan Volume: 10 Issue: 1 On page(s): ISSN: X Cited by: 4 INSPEC Accession Number: Digital Object Identifier: /JSEN Date of Current Version: 22 December 2009 ABSTRACT A Review: Cancer cell growth releases molecular biomarkers into blood that can be useful in diagnostic tests, e.g., serum biomarkers. The use of serum biomarkers involves an invasive sample collection procedure. Human exhaled breath is potentially a noninvasive source of cancer biomarker compounds. A few breath analysis studies have reported sensitivities > 90% and specificities > 80% using a suite of exhaled breath biomarkers to differentiate cancer subjects from controls. A significant challenge for establishing breath analysis as a feasible cancer diagnostic procedure is the lack of validated diagnostic procedure. We found over 2000 breath-related studies published since circa 1900 reporting on a wide variety of breath chemical analysis methods and diagnostic findings; only a small fraction of these studies were directly related to cancer molecular biomarkers in breath. Compared to other detectors and separation techniques, mass spectrometry and gas chromatography are most suitable techniques for breath analysis. Compounds detectable in exhaled breath, with potential diagnostic utility in cancer detection, include small gaseous molecules, volatile organic compounds, proteins, and DNA. The types of cancers previously investigated using chemical analysis of exhaled breath was breast, colon, liver, lung, ovarian, and stomach cancers. Lack of multiple studies using the same breath analysis method(s) precluded meta-analysis. Our review covers the reported methods on breath analysis and assumed exhaled biomarkers. This review makes available to other researchers a catalog of published data on breath analysis for cancer detection. We make recommendations to standardize methods for more accurate breath tests in cancer detection.

11 Characterisation of outer membrane protein profile of clinical isotope from human gastric H.Pylori Breath analysis Detection of insecticides in foods Drug metabolites Fate and level of steroid sterogenes and androgenes

12 Determination of polyacrylic aromatic hydrocarbons 20 organochlorine pesticides Phtalates in ham and sausages Detection of BTEX at trace levels at air atmosphere Urea breath test

13

14