TECHNOLOGY FOCUS - INSTRUMENTATION AND TESTING - Preferred Components: The sensor further comprises a reference electrode (24B) in contact with the solid support. At least a portion of the solid support is amorphous or crystalline. The sensor prior to being contacted by the analyte, the solid support: is characterized by the absence of a dopant; and comprises an insulator, a non-conductive polymer and a semiconductor. The solid support comprises a porous solid, where the volume of voids in the porous solid divided by the total volume of the porous solid is up to 0.7. The solid support comprises an electrolyte. The solid support comprises poly(ethylene terephthalate) (preferred), poly(ethylene oxide), polyvinylidene fluoride, polyethylene, polypropylene, polyethylene-naphthalate, polyphenylene sulfide, polycarbonate, PTFE, polypropylene oxide, acrylic resin, polystyrene, poly(styrene-acrylonitrile), poly(acrylonitrile-butadiene-styrene), PVC, chlorinated polyether and/or poly(chlorotrifluoroethylene). The solid support is characterized by the absence of salt. The solid support comprises a polymer which is hexa(polyethylene oxide)-lithium hexafluoroantimonate. The solid support has a thickness of 0.05-0.6 mm. The solid support further comprises a filler. The filler is electrically conductive or non-conductive. The filler comprises at least one inorganic filler and/or organic filler. The filler comprises at least one silicate, oxide, carbonate, sulfate, hydroxide, carbon, metal, glass, lignin, protein, synthetic fiber and/or cellulosic material. The solid support comprises glass and/or ceramic. The solid support comprises carbon and/or graphite. The working electrode and reference electrode each comprises a noble metal, which is gold, platinum, iridium, palladium (preferred), osmium, silver, rhodium, ruthenium and/or titanium. The analyte comprises: an oxidizing gas or a reducing gas, such as vaporous hydrogen peroxide (preferred), ethylene oxide and/or ozone; or a hydrogen-containing gas, such as atomic hydrogen, hydrogen sulfide, hydrogen sulfite, ammonia, methane, ethane, propane, butane, carbon monoxide, oxalic acid, formic acid, ascorbic acid and/or phosphorous acid. The sensor further comprises a reference electrode, and the working electrode and the reference electrode are formed by sputtering palladium on the solid support, where the solid support comprises poly(ethylene terephthalate) film. The thickness of the reference electrode and the working electrode is 40-150 nm. The working electrode and the reference electrode are separated from each other by 0.7-0.9 mm. The working electrode is connected to a potential control to maintain a stable voltage potential at the working electrode with respect to the reference electrode. The reference electrode is connected to a current amplifier. The current amplifier is connected to a current follower to convert gas concentration-related current to a voltage. The sterilant gas comprises vaporous hydrogen peroxide (preferred), ethylene oxide and/or ozone. The sterilant gas further comprises an alkaline gas, which is ammonia. The article: comprises an endoscope; is contaminated with a chemical and/or biological agent or is contaminated with bacterial spores, vegetative bacteria, virus, molds and/or fungus or is contaminated with a pathogenic chemical agent or is contaminated with a proteinaceous-infectious agent or is contaminated with rhinovirus, orthomyxovirus, Staphylococcus aureus, Streptococcus pneumonia, Escherichia coli, Salmonella, Clostridium difficile, Bacillus stearothermophilus and/or Clostridium sporogenes. Preferred Method: In method (M1): the pressure in the enclosed space is atmospheric pressure or below atmospheric pressure; the absolute pressure in the enclosed space is 1-2 atmospheres; and the temperature in the enclosed space is 15-90 degrees C. In method (M2): the sterilant gas flows in the vacuum chamber and contacts the amperometric gas sensor; the sterilant gas is mixed with a carrier gas to form a gaseous mixture, and the gaseous mixture flows in the vacuum chamber and contacts the amperometric sensor. The method (M2) comprises injecting pulses of the sterilant gas or a gaseous mixture comprising the sterilant gas and a carrier gas into the vacuum chamber. The pressure within the vacuum chamber is below atmospheric pressure. The temperature in the vacuum chamber is 15-90 degrees C. In method (M2), an article to be sterilized is positioned in the vacuum chamber, where the article: contains at least one aperture, hole, tube, open ended lumen, internal cavity, deadleg or flat surface; and is a medical and/or dental device.