The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Nov. 05, 1996
Filed:
Sep. 01, 1995
Applicant:
Inventors:
Assignee:
Fisons plc, Ipswich, GB;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H01J / ;
U.S. Cl.
CPC ...
250288 ; 250281 ;
Abstract
The invention comprises a method and apparatus for inductively-coupled plasma mass spectrometry which is particularly suitable for the determination of isotopic ratios. In order to improve the precision of such determinations, the nozzle-skimmer type interface of the mass spectrometer is arranged so that the ratio ##EQU1## is greater than 0.8 mB.sup.1/2, where d.sub.s is the diameter of the orifice in the skimming member, s is the spacing between the sampling member and the skiming member, and p.sub.1 is the pressure in the region between the sampling and skimming members. Although use of the invention slightly reduces the efficiency of the interface it results in more accurate isotopic ratio determinations.