Devices and methods for the detection of basic gases

A method for detection of a basic gas analyte which comprises the steps of:

• (a) contacting a fiber optic sensor with an environment that may contain a basic gas where the sensor comprises an optical fiber having a cladding, a fiber optic core and a layer comprising a triphenylmethane dye or combination of triphenylmethane dyes which undergo a color change on interaction with said basic gas wherein the dye has the formula:
• where M and M′ groups are selected from the group consisting of H and N(R)2 groups where the R group, which can be the same or different groups at different sites are selected from the group consisting of H, an alkyl group, an aryl group and an alkyl aryl group and X− is an anion;
• (b) measuring the optical response of the sensor on interaction with said environment;
• and
• (c) correlating the optical response to the presence of basic gas in the environment.

A method for detection of a basic gas analyte which comprises the step of

• (a) contacting a fiber optic sensor with an environment that may contain a basic gas where the sensor comprises an optical fiber having a cladding, a fiber optic core and a layer comprising a xanthene dye or combination of xanthene dyes which undergo a color change on interaction with said basic gas wherein the dye has the formula:
• where M and each R1-R4, independently of one another, are selected from the group consisting of H, an alkyl group, an alkylaryl group and an aryl group and wherein X− is an anion;
• and
• (b) measuring the optical response of the sensor on interaction with said environment.