Spectrometer with validation cell

Abstract

A valid state of an analytical system that includes a light source and a detector can be verified by determining that deviation of first light intensity data quantifying a first intensity of light received at the detector from the light source after the light has passed at least once through each of a reference gas in a validation cell and a zero gas from a stored data set does not exceed a pre-defined threshold deviation. The stored data set can represent at least one previous measurement collected during a previous instrument validation process performed on the analytical system. The reference gas can include a known amount of an analyte. A concentration of the analyte in a sample gas in a measurement cell can be determined by correcting second light intensity data quantifying a second intensity of the light received at the detector after the light passes at least once through each of the reference gas in the validation cell and a sample gas containing an unknown concentration of the analyte compound. Related systems, methods, and articles of manufacture are also described.

Description

[0001] Cross References to Related Applications [0002] This application claims priority to US Provisional Application Serial No. 61 / 405,589, filed October 21, 2010, and US Invention Application Nos. 13 / 026,921 and 13 / 027,000, filed February 14, 2011. technical field [0003] The subject of the present application relates to the quantification of gas-phase concentrations of chemical analytes, for example using a spectroscopic analysis system comprising a verification cell with one or more reference gases or with a full or partial vacuum. Background technique [0004] Trace gas analyzers may require periodic verification of the long-term fidelity accuracy of the concentration measurements they produce relative to, for example, the performance of the analyzer, which is either factory calibrated or derived from national or international standards Bureau (including but not limited to, National Institute of Standards and Technology, National Institute of Standards and Technology...

AI Technical Summary

Problems solved by technology

Typically, bottled gas mixtures do not provide accurate, bureau-derived verification for such low-concentration measurements

Permeation tube verification techniques are also not suitable for providing reliable verification results for ethylene and propylene contamination measurements

In addition to the extreme demands on temperature stability and flow control, permeation tube devices are often not capable of reliably delivering trace gas concentrations below 10 ppm

Typical optical and TDL trace gas analyzers measuring below 50ppb cannot simultaneously support accurate measurement of trace gas levels above about 10ppm

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