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Analytical Chemistry

New And Notable At Pittcon: Analytical Instrumentation

by Stephen K. Ritter
April 4, 2011 | A version of this story appeared in Volume 89, Issue 14

Active Spectrum unveiled the Benchtop Micro-ESR, a low-cost, personal-sized electron spin resonance spectrometer for measuring the type and concentration of free radicals. The Micro-ESR was originally developed for the Navy to monitor oxidation and soot content in ship motor oil. But it’s now being targeted for general-use diagnostic testing and for academic research and teaching labs. Much smaller than conventional ESR instruments, which can take up most of a small room, the Micro-ESR has simple sample-tube insertion and operates at 3.4 or 9.5 GHz with a magnetic field sweep range of up to 400 gauss with submicromolar sensitivity. Applications include testing motor oil and lubricants in auto shops; monitoring asphaltene and vanadium compounds in crude oil production; spin-trapping experiments for shelf-life analysis of beer, wine, vegetable oils, and solid foods; and spin-trapping of NO <sub>x </sub> and RO x species in biomedical research. Active Spectrum also offers an on-line Micro-ESR for continuous, real-time process measurement of free radicals.

(4) Horiba Scientific premiered the AquaLog spectrofluorometer, the first instrument capable of simultaneously measuring both absorbance spectra and fluorescence spectra. This combination enables faster excitation-emission matrices spectroscopy (EEMS) for water-quality research to identify and quantify the components of natural and man-made chromophoric dissolved organic matter (CDOM), which includes humic acid, chlorophyll, gasoline, and agricultural chemical residues. EEMS on conventional instruments can take hours to scan the full emission spectrum at each increment of the excitation wavelength, but the AquaLog can acquire the full emission spectrum in one shot—it is about 100 times faster than other fluorescence instruments. AquaLog’s features include a 150-W xenon lamp with enhanced UV output, double-excitation monochromator for stray-light rejection, photodiode array detector for absorbance spectra, and thermoelectric-cooled charge-coupled device (CCD) array detector for collecting rapid emission spectra. The software comes with a suite of National Institute of Standards & Technology spectral calibration and correction procedures.

(5) Spectro Analytical Instruments highlighted a new generation of the Spectro Midex microsized X-ray fluorescence spectrometer, which is faster and easier to use than its predecessors. The instrument comes with an air-cooled low-power X-ray tube and a silicon drift detector capable of processing up to 250,000 pulses per second. The Spectro Midex was designed particularly for the electronics, precious metals, automotive, and aerospace industries, as well as forensic laboratories. With its mapping feature, the instrument is useful for examining printed circuit boards and searching for defects in finished automotive components. One surprising application, according to the company, stems from the recent skyrocketing price of gold, which has revitalized the scrap gold industry. Traditionally, gold brokers use a flame test, acid test, or conductivity meter to test for gold purity to determine buying price from pawn shops, Internet marketers, and jewelers. But the Spectro Midex is now capable of getting within about 0.2% accuracy of the standard gold assays. This capability is allowing pawn shop owners and jewelers to cut out brokers and pocket more money by conducting their own assays and selling straight to gold refiners.

DANI Instruments exhibited the Master TOF GC/MS system, which couples a fast gas chromatograph with one of the fastest scanning mass spectrometers on the market—up to 1,000 spectra per second over a 1,024-dalton mass range. The mass spectrometer uses orthogonal acceleration optics with a 16-cm flight tube and reflectron to generate a 32-cm ion path and mass resolving power of 1,500—all in a compact benchtop system. Other key components of the Master TOF include a fast heating and cooling GC oven that permits high sample throughput via an autosampler, and deconvolution software that allows tightly bunched peaks to be resolved and characterized. The instrument is geared toward GC and GC/GC analysis of chemically complex samples such as wines, perfumes, biodiesel, and pesticide residues in foods.

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