New
Products
Immunoanalyzer KinExA is an automated fluorescence detection instrument designed to per form kinetic exclusion assays for ligand-binding experiments as well as competitive ligand binding, competi tive immunoassays, and sandwichformat immunoassays. Kinetic exclu sion permits the direct determination of free ligand or antibody in a sample without derivatization and can be used for antibody or biomolecule deter minations in serum, milk, and other complex biological matrices. Polymer beads are used as the solid phase for the kinetic exclusion and other assays. The beads are coated with an antigen or ligand for the anti body or other biomolecule being deter mined, suspended in buffer, and then flowed into a capillary flow cell, where they are trapped on a screen. Sample is flowed through the cell at a high enough rate that any biomoleculeligand or antibody-antigen complexes already formed in the sample will not dissociate. Under these conditions, only free biomolecule or antibody binds to the coated particles. Once the sample has passed over the particles, a fluorescence-labeled second antibody or other fluorescent reagent is in
ual and automatic injection modes are available, and the Model 510 selection valves offer four different buffers per pump. Beckman 1 4 1 0
GC
jected to allow the determination of free analyte in the original sample. The flow cell is embedded in a lens and backed with a reflector to increase the efficiency of bothfluorescenceex citation and the collection of fluores cence emission. When used with a conventional epi-illumination filter fluorometer, slightly more than 50% of the fluorescence emitted in the active region of the flow cell reaches the de tector. The fluorescence signal is moni tored continuously in real time. The system includes an in-line degasser, and all pumps and valves are electrically actuated and controlled through Windows-based software that allows the user to specifyflowse quence, times, and rates. Multiple de terminations per sample can be per formed automatically. Sapidyne • 408
FIDamat 5E is a flame ionization detector for GC designed to measure total hydro carbon content in air as well as determine corrosive and condensing gases. Appli cations include monitoring the airborne hydrocarbons produced by smokestacks, waste incinerators, power stations, coating equipment, and automobile exhaust sys tems. The detector has a dynamic range from < 1 ppm to 99.999 ppm. Siemens • 411
Spectrophotometry PELA-1016 0745° reflectance spectros copy accessory is designed for use with the Perkin Elmer Lambda 900 spectropho tometer. It measures reflectance and color parameters in both 0° incident and 45° collection geometries and features a 50-mm Spectralon collection sphere, transfer optics, and both PbS and PMT de tectors. The accessory mounts in the sample chassis of the spectrophotometer and is compatible with all system hard ware and software. Labsphere • 412
LITERATURE INSTRUMENTATION
band light sources, multiwavelength la sers, and tunable lasers. Operating from 480 to 780 nm without the need for refocusing, these lenses combine diffractive and refractive elements to reduce chro matic aberration by a factor of 10 and im prove off-axis performance over that of standard achromatic doublet lenses. Melles Griot • 409
Radio-HPLC β-RAM Micro is an in-line radioisotope de tector for microbore HPLC. The detector, which is available with a range of count ing cells for β-, positron-, and low-energy yemitters, accommodates eluent flows of 50-300 uL/min. Dead volume for a solidscintillator system is 0.7 \xL and < 4 pL for a liquid scintillation system. The detector Protein p u r i f i c a t i o n can be connected in line with a mass spec BioSys 500 Series workstations are dedi trometer. IN/US Systems • 407 cated chromatography systems for pro tein purification that operate in isocratic Laser s p e c t r o s c o p y or gradient mode. The systems deliver Dapromat hybrid apochromatic lenses are buffer gradients at up to 30 mL/min and designed for applications involving broad accommodate pressures to 2500 psi. Man622 A Analytical Chemistry, October 1, 1995
ICPMS Literature describes the UV MicroProbe laser for laser ablation ICPMS. The bro chure provides a system overview and application notes on direct analysis of transparent minerals and independence of mineral orientation. Features of the optics, sampling stages, and control soft ware are described. Fisons • 413
For more information, please circle the appropriate numbers on one of our Reader Service Cards.
Food analysis "Food and Beverage Analysis Guide" con tains information on 260 food reference standards, immunoassay kits, and GC and HPLC applications. Techniques for sam ple preparation such as SPME, SPE, and SFE are also described. The guide sug gests appropriate products for use with a list of AOAC methods. Supelco • 414
TGA for gas mixture interactions IGA-003 automated gravimetric ana lyzer is designed to measure the mag nitude and kinetic parameters of sorp tion reactions between the sample and variable-composition mixed gases. Up to four gases can be mixed to specified compositions before introduction to the analyzer. Methods for this analyzer include measurement of multicomponent isotherms, temperature-pro grammed oxidation and reduction as says, and catalyst characterization. An internal gas feed introduces the gas mixture into the sample reactor just below the sample, and a diffuser ring at the inlet homogenizes the gas. Flow rates range from 100 to 1000 mL/min, and automated thermal ramping can be performed at rates of 0.1-20 °C/min at temperatures to 1000 °C. A separate purge stream can be used to protect the microbalance from corrosive gases, and gas streams can be humidified to study water sorption in vacuum-labile materials. High flow rates can be used to re duce the depleted zone at the sample surface so that the sample is exposed to a constant gas or vapor composition. For measurement of multicomponent isotherms (e.g, for gas separation pro cesses) , the pressure in the system is changed at constant flow rate and then regulated during mass relaxation to the new equilibrium conditions. The analyzer controller can also be programmed to switch between single-
Petroleum analysis Brochure describes the Reformulyzer GC system, which is designed for the analy sis of reformulated gasolines. The system determines paraffins, isoparaffins, ole fins, naphthenes, and aromatic com pounds in FCC gasoline, finished gaso line, naphthas, and other intermediates. It can also be used to determine oxygenates. AC Analytical Controls • 415
or multicomponent gas streams either at predefined times or on completion of a particular reaction. This feature permits the study of catalytic reac tions or cyclic behavior to characterize sample regenerability. The IGA-003 can also be interfaced with a mass spec trometer to perform TGA/MS of spe cies generated by gas desorption or de composition. The controlling software operates in three interface modes. The interac tive chart mode logs parameters such as weight, pressure, temperatures, flow rate, and gas composition and dis plays them as a function of time. The isothermal mapper determines multicomponent isotherms at specified gas compositions and flow rates and pro vides real-time analysis of the mass relaxation to derive adsorption rates of gas components. The automatic event sequencer is designed for protocol setup and recall. Hiden Analytical • 416
Confocal fluorescence correlation spectroscopy ConfoCor fluorescence spectrometer uses confocal laser optics to observe molecular diffusion, concentration, and reaction or binding kinetics of analytes in very small volumes by fluores cence correlation spectroscopy. The sensitivity of the method permits rapid determination of these properties for molecules in a single cell or viral particle and increases with decreased analyte concentration. Complexation reactions such as antibody or ligand binding or nucleic acid hybridization can be observed in solution. The spectrometer's confocal optics focus a laser into a volume of ~ 1 fL (about the volume of an E. coli cell). The laser excites fluorescence in the molecules present, and the fluores cence is conducted by confocal optics to a single-photon detector. If the sam ple concentration is < 1 μπιοΙ/L, only a few molecules will occupy the observa tion region at a time. The fewer molecules in the re gion, the larger the signal fluctuation whenever individual molecules move in or out. Complexation of the analyte molecules with a ligand or an tibody changes the diffusion param eters for the analyte. The system in cludes dedicated correlation software for calculating diffusion and kinetic parameters as well as analyte concen tration. Carl Zeiss 1 4 1 7
Analytical Chemistry, October 1, 1995 623 A
