An implant for detecting at least one analyte in a body fluid, in particular an eye fluid, is proposed. In some embodiments, a reaction chamber is configured to receive a fuel gas and maintain the gas at a temperature within the reaction chamber that is above an autoignition temperature of the gas. The seal can be conformable with the concave interior side and can define a seal aperture substantially aligned with the flashing aperture. The invention is useful in providing three-way catalytic exhaust converters for internal combustion engines. The membrane is especially useful for filtering liquids, such as wine and juice, so as to remove bacteria, gel, and solid particles from the liquids.