Abstract: The invention provides an improved apparatus for the detection of polar vapors in a gas which avoids the need for liquid reagents and requires little maintenance. In its simplest form the apparatus comprises a body member defining a passage through which a gas stream may be caused to pass; an ionizing source for ionizing the gas stream; and a collector electrode positioned in the passage downstream of the ionizing source for collecting ions carried by the gas stream. Improved performance can be obtained by the provision of means for selectively removing uncombined gas ions from the gas stream between the ionizing source and the collector electrode while permitting ion clusters formed on polar molecules to remain therein.

Abstract: A method and device for detecting bacteria by forming an immunoassay ladder sing a biological substance (Ag) adsorbed onto a surface, to which has been added an immunological biochemical ladder (Ab) and beta-galactosidase enzyme (gal) to form a Ag-Ab-gal system. The system is added to an aqueous solution of an enzyme selected from ortho-nitrophenylgalactopyranoside and ortho-nitrophenylgalactosidase enzyme. The enzyme reacts with the gal to produce ortho-nitrophenol (ONP) such that the amount of ortho-nitrophenol (ONP) produced may be detected by measuring the vapor pressure generated by the ONP using an ion mobility spectrometer monitor. The pressure of the ONP is in proportion to the amount of biological substance present in the system. In a preferred embodiment, the ion mobility spectrometer monitor includes display means for indicating the quantity of bacteria measured.