Abstract: A gas chromatograph with multiple valves is disclosed. An embodiment of the multi-valve gas chromatograph includes multiple valves, multiple thermal conductivity detectors (TCD's), and a manifold. This allows separation and measurement of a gas sample in one compact integrated unit. The unit is particularly desirable because the solenoids associated with the valves are attached directly to the underneath of the manifold, thus eliminating the need for tubing between the solenoids and the valves. Other features may also be present. For example, a leak free multi-valve block may include a first temperature zone heating the valves and detectors and a second temperature zone heating the columns. The leak free feature may be achieved by placement of tightening screws through the center of each valve. Carrier gas insertion areas may be provided in the multi-valve block to improve performance.

Abstract: A micro-machined thermal conductivity detector for a portable gas chromatograph. The detector is highly sensitive and has fast response time to enable detection of the small size gas samples in a portable gas chromatograph which are in the order of nanoliters. The high sensitivity and fast response time are achieved through micro-machined devices composed of a nickel wire, for example, on a silicon nitride window formed in a silicon member and about a millimeter square in size. In addition to operating as a thermal conductivity detector, the silicon nitride window with a micro-machined wire therein of the device can be utilized for a fast response heater for PCR applications.

Abstract: A gas chromatograph with multiple valves is disclosed. An embodiment of the multi-valve gas chromatograph includes multiple valves, multiple thermal conductivity detectors (TCD's), and a manifold. This allows separation and measurement of a gas sample in one compact integrated unit. The unit is particularly desirable because the solenoids associated with the valves are attached directly to the underneath of the manifold, thus eliminating the need for tubing between the solenoids and the valves.

Abstract: An inspection apparatus for gas detectors is disclosed which comprises an open-feasibly air-tight testing reservoir in which gas detectors to be tested can be positioned, an air-tight dispensing reservoir for mixing the gas to be tested, a vacuum device for making the testing reservoir and the dispensing reservoir in vacuum, a gas supply device for supplying at least a standard gas and a diluting gas to the dispensing reservoir, and a controlling means for controlling the dispensation of the gases to each of the above-described components of the invention. By means of the invention, the executions of the mixing of the gases and the detection of the gas detector are substantially simultaneous and thus the time consumption as well as the amount of required gas are reduced. Moreover, an automatic control is available when the inspection apparatus of the invention is equipped with a computer.

Abstract: A method for detecting an analyte of interest present in a mixture at an ultralow concentration includes selecting a radioactive derivatizing agent comprising a multiphoton-emitting radioisotope moiety and a moiety reactive with the analyte of interest, the radioisotope moeity being bound to the derivatizing agent by a bond that is stable under the conditions employed in the other steps of the method, derivatizing the analyte of interest with the derivatizing agent, separating the analyte of interest from other components of the mixture by chromatography, and detecting the analyte of interest using multiphoton detection. The derivatizing step may be performed before or after fractionation. A radiophore for multiphoton emission enhanced chromatography has a first moeity bound to a multiphoton-emitting radioisotope, and a second moiety that is reactive with a functional group of an analyte of interest.

Abstract: A silicon-based carrier matrix having a high ratio of surface area to volume is intended for use in integrated microanalysis systems. The carrier matrix comprises at least one layer of microporous silicon on a body of monocrystalline silicon. A method for producing the carrier matrix comprises electrochemical etching of a body of monocrystalline silicon, thereby to form at least one layer of microporous silicon on this body. The use of the carrier matrix for chemical sensors in integrated microanalysis systems, as well as in various sorts of chromatography, is also disclosed.