An Ultra-Sensitive Mass Spectrometer System for Quantitative Biological Studies

A dedicated minicomputerized high pressure ionization mass spectrometer with pulse-counting electronics was developed for quantitative biological studies using the molecular isotope dilution method. The two-chamber differentially pumped vacuum system maintained by two 800 l/s turbomolecular pumps contains a /sup 3///sub 8/-in. quadrupole analyzer, ion detector, and low pressure ion collection optics. Ions that are produced in the ion-molecule reaction chamber and initiated by the /sup 63/Ni source are carried through a 40 ..mu..m aperture by the N/sub 2/ gas jet. The low pressure optics focus the ions into the quadrupole mass spectrometer while the bulk of the gas is pumped away. The signal from the pulse-counting detector is transmitted directly to a PDP 8/c minicomputer via an optically isolated, specially designed interface unit. Sensitivity in the single-ion monitoring mode for 2, 3, 7, 8-tetrachlorodibenzo-p-dioxin (5fg) has been determined.

[1]  H. Abe,et al.  A new technique for the detection of metabolites labelled by the isotope 13C using mass fragmentography. , 1976, Biomedical mass spectrometry.

[2]  R. Delongchamp,et al.  Mass spectrometry in toxicology: I—calculation of theoretical isotopic abundances and optimum ion dwell time for a 2,3,7,8‐tetrachlorodibenzo‐p‐dioxin pharmacokinetic study , 1975 .

[3]  R. Wyatt,et al.  Mass‐fragmentography of nanogram quantities of biogenic amine metabolites in human cerebrospinal fluid and whole rat brain , 1975 .

[4]  B. Millard,et al.  A comparison of unlabelled and labelled internal standards for quantification by single and multiple ion monitoring , 1975 .

[5]  D. Bier,et al.  Multiple ion detection by accelerating voltage alternation in conjunction with voltage sweeping. , 1974, Biomedical mass spectrometry.

[6]  P. Vestergaard,et al.  Mass fragmentography of morphine and 6-monoacetylmorphine in blood with a stable isotope internal standard. , 1974, Biomedical mass spectrometry.

[7]  A. Boulton,et al.  Detection and quantitative analysis of amphetamine. , 1974, Biomedical mass spectrometry.

[8]  D. I. Carroll,et al.  Subpicogram detection system for gas phase analysis based upon atmospheric pressure ionization (API) mass spectrometry , 1974 .

[9]  N. Matwiyoff,et al.  Stable isotope tracers in the life sciences and medicine. , 1973, Science.

[10]  R. N. Stillwell,et al.  New picogram detection system based on a mass spectrometer with an external ionization source at atmospheric pressure , 1973 .

[11]  L. Bertilsson,et al.  Quantitative determination of 5-hydroxyindole-3-acetic acid in cerebrospinal fluid by gas chromatography-mass spectrometry. , 1972, Analytical chemistry.

[12]  M. H. Aprison.  Advances in biochemical psychopharmacology: Volume 1, edited by E. Costa and P. Greengard, Raven press (1969) , 1970 .

[13]  A. Frigerio,et al.  Mass spectrometry in biochemistry and medicine , 1974 .

[14]  Donald Joseph David,et al.  Gas chromatographic detectors , 1974 .