GC
DNA analysis
Technical Report No. 9109 describes pro tocols using GC with nitrogen-phospho rus detection to screen the serum of race horses for drugs such as procaine, amanta dine, and rimantadine. The performance of the pGold 902 NPD is described and il lustrated, and sample chromatograms are presented for spiked horse serum sam ples. Finnigan/Tremetrics • 411
Brochure describes a modular multiple in situ hybridization system for DNA analy sis. Incubation and thermal cycling, strin gency washing, and signal detection are discussed. Specifications, accessories, and ordering information are included in the brochure, which is illustrated with photos of the instrument components and with photomicrographs of DNA and RNA detected by in situ hybridization. Shandon Lipshaw • 413
ISE "Guide to Ion-Selective Measurement" de scribes the principles of operation and analytical methods for ion-selective elec trodes. Topics include selectivity, interfer ences, and types of electrodes; analytical methods and applications; maintenance; and standard solutions for ISE measure ments in addition to a glossary of terms. Mettler-Toledo B412
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Miniature cryogenic STM system MiniCryoSTM is a miniaturized scan ning tunneling microscope designed for operation at very low tempera tures. Applications include surface characterization of low-temperature superconducting materials. The min iature microscope is 25 mm in di ameter and is fitted to a rod inside a tube that can be lowered into a cryo stat for operation at temperatures from 1.5 Κ to 300 K. The micro areas 1-8 pm on a side to be scanned scope's small diameter and nonferrowith resolution down to 0.02 Â at 4.2 K. magnetic construction allow it to be Advance, retract, speed, and direcinserted in the bore of a high-fieldtion parameters are manually constrength magnet for investigation of trolled. The microscope has two bias the Meissner effect and other proper contacts and a six-contact option for ties of superconductors. The STM the device carrier. Approach control is tip can also be used as the electron automated with TTL input from STM source for ballistic electron emission electronics, and the microscope intespectroscopy of interfaces. grates with an STM parallel-processThe microscope consists of a ceram ing controller for imaging. The unit can be retrofitted to a flow or bath cryoic-tube scanner with an inertial-drive stat or supplied as a fully integrated inmotor for automatic approach at cryo genic temperatures. The sample is strument with its own cryostat. It is compatible with most existing STM placed on the scanner and lowered electronics and can be supplied with into a cryostat for operation. Three pi ezoelectric tip options permit sample an STM controller. Topac 1 4 1 4
Optical trapping LaserTweezers 2000 is an instrument for optical trapping of individual cells; organelles, chromosomes, and other subcellular components; and microscopic particles. Optical trapping allows these small particles to be manipulated using the physical force of laser light and eliminates the problem of sample contamination through contact with forceps or other mechanical tools. The system, which incorporates a laser module, focusing optics, and a controller, mounts on the side of an Axiovert inverted microscope and can be used in conjunction with fluorescence imaging and laser-based microdissection. The instrument focuses an IR laser beam with < 1pm resolution and 2-pm repeatability on an object of interest. A trackball controller is used to select and move the object to its target position through click-and-drag commands. The object can be held in place or moved at up to 270 pm/s for 25 mm along the χ and y axes. In the ζ direc tion, travel spans the full range of the microscope focus drive. The LaserTweezers 2000 incorpo rates an 830-nm laser operating at 200 mW or a 980-nm laser operating at 750 or 1000 mW. An entry-level version, the LaserTweezers 100, replaces the fluorescence cube of an inverted micro scope and features a 100-mW laser module and a motorized x-y stage with a joystick controller. Applications in clude modeling neuronal pathways and observing chemical interactions be tween cells. Carl Zeiss 1 4 1 5
Analytical Chemistry, September 1, 1995 565 A
