Abstract: This invention relates generally to a method of operating an ion trap mass spectrometer to determine the resonant excitation frequencies of trapped ions. This can be achieved by: (1) introducing sample ions into the ion trap volume: (2) adjusting the trapping fields so that parent ions having a mass-to-charge ratio of interest which are to undergo collision induced dissociation (CID) are trapped; (3) applying an excitation voltage of predetermined frequency and amplitude across the end caps of the ion trap; (4) scanning the frequency of the excitation voltage in a first direction and monitoring for ejection of the parent ions; (5) repeating steps (1) through (3) and scanning the frequency of the excitation voltage in an opposite direction and monitoring for ejection of the parent ions; (6) averaging the frequencies at which the ions are ejected; and (7) applying that frequency in a subsequent MS/MS scan to promote CID of the parent ions to form daughter ions.

Abstract: An improved system and method for high resolution gas chromatography (GC) is disclosed. This invention involves the use of fused silica open tubular capillary columns having a conductive exterior coating and an arrangement for electrically coupling a power source to such coating, whereby it is now possible to effect direct resistive heating of the capillary column while controlling the temperature thereof. Such control is achieved by measurement of the resistance of the conductive coating, correlating such resistance with the temperature of the column and increasing or decreasing the electrical power supplied to such coating, as appropriate, to effect the desired adjustment in column temperature. Because of the low thermal mass of the column and the conductive coating, temperature changes can be effected readily thereby improving the speed of such separation and reducing the time interval between resolution of successive samples.

Abstract: This invention relates generally to a quadrupole ion trap mass spectrometer and method of operation and more particularly to an ion trap mass spectrometer in which pulses of energy of predetermined frequencies are applied across the end caps to independently and sequentially excite ions of different masses trapped in the ion trap to perform parent scanning, neutral loss scanning and selected reaction monitoring.

Abstract: A decoding signal processing mechanism preserves the use of a single high data rate encoder at a transmitter site, so that the input data may be continuously encoded and transmitted, while using multiple low data rate decoders at the receiver site in such a manner that "end effects" are avoided and the performance of high data rate decoding is attained. At the transmitter site, digital information signals are encoded at a first encoding rate and then transmitted over a communication channel to a receiver site. At the receiver site signals to be decoded are coupled to a respective one of a plurality of decoders which decode, at a second rate less than said first, encoding rate, respective overlapping blocks of received encoded digital information signals and derive respective portions of the digital information signals. The decoded outputs of the decoders are combined to recover the digital information signals.

Abstract: A tandem quadrupole-based mass spectrometer including a highly efficient intermediate fragmentation stage. The disclosed fragmentation stage employs collision-induced dissociation (CID), in an electrodynamic focus device, which may be a quadrupole operated in a broad band filter mode. The disclosed CID process occurs at low energy (e.g., less than 1 keV, but preferably 2 eV to 100 eV), and is quite different from the high energy (e.g, greater than 1 keV, and typically 3 keV to 10 keV) CID process in prior tandem instruments such as mass-analyzed ion kinetic energy spectrometry (MIKES) systems. The efficiency of the present CID fragmentation is as high as 65%.