Patent Document ID: 20090216462
Application ID: 11885212
Patent Flag: 0

Claim One:
1. A chemical analysis method for determining the concentration of a gaseous component of interest in a sample gas comprising a gaseous matrix, comprising the steps of: (a) directing light from a tunable diode laser through an inert gas contained in a sample cell over a selected range of n wavelengths to a light detector to produce a range of baseline signals I 0 n from the light detector, the inert gas being essentially transparent over the selected range of n wavelengths; (b) digitizing the range of baseline signals I 0 n from the light detector; (c) storing the digitized baseline signals I 0 n in a digital computer; (d) directing light from the tunable diode laser through the sample gas contained in the sample cell over the selected range of n wavelengths to the light detector to produce a range of sample signals I S n from the light detector; (e) digitizing the range of sample signals I S n from the light detector; (f) storing the digitized sample signals I S n in a digital computer; (g) calculating a spectrum in the digital computer according to the equation I(n)=(I 0 n−I S n)/I 0 n; (h) producing a signal from the computer indicative of the concentration of the gaseous component of interest by using spectra of a known concentration of the component of interest in the inert gas stored digitally in the computer, the spectrum of step (g) and a multivariate regression algorithm programmed in the computer.