Paul A Jacobs

US Patent:

62696807, Aug 7, 2001

Filed:

Jun 21, 1999

Appl. No.:

9/337727

Inventors:

John F. Prieve - Seattle WA
Paul Taylor Jacobs - Trabuco Canyon CA
Szu-Min Lin - Laguna Hills CA
Richard B. Timmons - Arlington TX

Assignee:

Ethicon, Inc. - New Brunswick NJ

International Classification:

G01N 2135

US Classification:

73 2321

Abstract:

An improved apparatus and method for measuring the concentration of hydrogen peroxide vapor or gas in a sterilization chamber. The hydrogen peroxide is measured spectrophotometrically in the ultraviolet region between 200 and 400 nm. Because water vapor does not absorb in the ultraviolet region, it does not interfere with the determination of the concentration of the hydrogen peroxide vapor. Although organic compounds have absorbances in the ultraviolet region, the organic compounds are removed by evacuating the sterilization chamber to low levels before doing the hydrogen peroxide determination. The ultraviolet light source is either a low pressure mercury vapor lamp with an emission at 254 nm or a deuterium lamp with an optical filter selective of 206 nm light. A movable gas cell can be used to measure the hydrogen peroxide concentration at various areas in the sterilization chamber. The measurement system can be combined with a feedback loop to control the concentration of hydrogen peroxide in the sterilization chamber.