FEATURE
New Analytical Instruments at Pittcon '95 Manufacturers display faster, smarter, and tougher instruments for environmental analysis. ALAN
NEWMAN
F
aster, smarter, tougher. One or more of those attributes characterizes much of the commercial analytical instrumentation and many accessories for the environmental market unveiled in New Orleans this March at Pittcon, the major exhibition of analytical equipment. Those features are designed to serve environmental laboratories that compete to run more samples in less time, employ analysts with less and less formal training, and still comply with regulations. In addition, the growing sophistication of both software and instruments increases the opportunities for developing new analytical methods and automated systems. This overview presents a few of the significant offerings at Pittcon, particularly in mass spectrometry and gas chromatography; many more are listed in the Analytical Products section (p. 227A).
Mass spectrometry Mass spectrometry (MS) has long been a definitive method for identifying analytes, especially when used as a detector for gas chromatography (GC). In recent years, ion trap MS (ITMS) has grown in popularity because the design of these compact systems offers highly sensitive analysis of trace-level pollutants in a benchtop instrument. In addition, ITMS supports a number of "smart" techniques, such as MS/MS and chemical ionization, as routine methods in instruments with relatively affordable prices. However, because the ion source and mass analyzer are combined in ITMS, high concentrations of neutral molecules in the trap can sometimes react with trapped ions to generate new, unwanted ions or skew ion ratios in the mass spectrum. To avoid this problem, Finnigan MAT (San Jose, CA) redesigned the basic ion trap by pulling the ion source away from the trap. In effect, says the manufacturer, their new GCQ system for GC/MS combines an ion trap with a classic quadrupole MS ion source and detector. According to Finnigan MAT, spectra 2 1 2 A • VOL. 29, NO. 5, 1995 / ENVIRONMENTAL SCIENCE & TECHNOLOGY
Varian's SPME II, which extracts analytes without solvents.
from the GCQ and GCQ Tandem (for MS/MS) closely match the spectra of quadrupole MS instruments, which should simplify library matching. The only trade-off is that operators can't switch from electron to chemical ionization in the same run. GCQ systems are designed as benchtop GC/MS detectors with a mass range of 1000 amu; PCcontrolled operation uses a Windows NT environment for multitasking, selective ion monitoring, and automated running. GCQ comes with Finnigan's gas chromatograph, but it will connect with Varian or Hewlett-Packard (H-P) systems. Remove the gas chromatograph and the GCQ will work with direct ex0013-936X/95/0929-212A$09.00/0 © 1995 American Chemical Society
posure probes or as a membrane introduction MS (see p. 215A). Varian (San Fernando, CA) inaugurated new options for its Saturn GC/ITMS system, introduced last year: MS" for difficult-to-identify compounds, multiple reaction monitoring to allow MS/MS analysis of coeluting compounds to include isotopically labeled internal standards, ion storage in the ion trap as narrow as a single mass unit, and automated methods development for MS/MS. For those interested in speed, Meridan Analytical Systems (Okemos, MI) was offering the fast chromatographic detector (FCD) time-of-flight (TOF) MS system for GC/MS. TOFMS traditionally has been a technique used by biochemists for high-mass analyses. However, in application studies, the manufacturer reported analyzing 53 volatile organic compounds in < 2 min. The FCD can produce up to 10,000 full mass spectral range spectra per second, sum the information, and generate 1-1000 spectra per second. Because of this speed, the FCD system works well as a detector for the narrow peaks eluting from capillary GC. Meridan offers mass ranges of 650 or 1000 amu, depending on the unit. However, TOFMS precludes MS/MS techniques. Sector MS instruments offer high resolution and sensitivity, but are generally too costly and complex for the environmental community. Jeol (Peabody, MA) has succeeded in producing the modestly priced, sector-based benchtop GCMate mass spectrometer for GC/MS. The instrument relies on a compact, double-focusing ion optics system and supports selective ion monitoring and positive or negative ionization. Mass range is 1000 amu, says the manufacturer, and the sector optics reduce background interferences and improve sensitivity. MS/MS and chemical ionization are available as options. GCMate comes with an H-P 6890 gas chromatograph, but can be connected to a liquid chromatograph using either electron spray or atmospheric chemical ionization interfaces.
tractor (SFE, Model 7680T), purge-and-trap concentrator (Model 7695), and headspace sampler (Model 7694). Perkin-Elmer's (Norwalk, CT) new AutoSystem XL gas chromatograph also supports regulatory compliance and includes a variety of smart features. Built into the instrument are a liquid autosampler, temperature-programmable inlets, and programmable pneumatic control. The AutoSystem features a mode to isolate the column and detector from high levels of solvent, allowing chromatographers to inject large amounts of solvent without degrading performance; another mode prevents volatile components from entering the GC column. Several injectors are available, including split-splitless and programmable on-column capillary injectors. A number of gas chromatograph add-ons accelerate and improve analyses. Scientific Instrument Services, Inc. (Ringoes, NJ) introduced TD-2, a shortpath thermal desorption unit for volatiles and semivolatiles, which sits on top of the injector port of a gas chromatograph. The short path eliminates transfer lines and, says the manufacturer, optimizes the delivery of analytes. TD-2 thermally desorbs analytes from glass-lined stainless steel tubes loaded with absorbent materials, such as Tenax or activated charcoal, or any other solid. The tube can be "ballistically" heated up to 350 °C by a microprocessor, which also remotely starts the gas chromatograph, mass spectrometer, and recorders. Varian unveiled the SPME II, an upgraded version of its solid-phase microextraction (SPME) autosampler system for its gas chromatograph (for more on SPME, see ES&T, 1994, (28)13, 569A). The SPME relies on a thin, coated fiber used to extract analytes quickly from solutions and into the gas chromatograph. In the Varian system, the SPME fiber is inserted into 2- or 10-mL vials on an autosampler, and the collected analytes are desorbed directly into the gas chromatograph. Varian claims that with the SPME II mounted on its fast GC system, the Star 3000 series, analysis time for BTEX (benzene, toluene, ethylben-
Gas chromatography and accessories Capillary and other fast GC techniques will be moving out of the research laboratories and into routine use in the next few years. These techniques should significantly decrease sample run times and increase productivity. However, gas chromatographs will require new inlets and electronics to handle these sophisticated techniques (see ES&T, 1994, 25(8), 369A and 23(9), 428A). New GC instruments and accessories are being introduced to accommodate these methods. Hewlett-Packard's (Palo Alto, CA) new 6890 gas chromatograph features electronic pneumatics control to improve reproducibility, sensors to compensate for temperature or barometric variations, a variety of gas valve operations, six independently controlled heating zones in addition to the oven, and several inlet options including the split-splitless capillary inlet. The 6890 is designed to meet Good Laboratory Practices and other regulatory compliances as well as ISO r e q u i r e m e n t s . A host of automated accessories are available for the system including a liquid sampler, supercritical fluid ex-
Perkin-Elmer's new automated GC system. VOL. 29, NO. 5, 1995 / ENVIRONMENTAL SCIENCE & TECHNOLOGY • 2 1 3 A
tions running with the same or different methods simultaneously. Dionex (Sunnyvale, CA) introduced a new twist on conventional solvent extractions. The company's new ASE 200 uses "small" amounts of solvents at high pressures and temperatures to extract analytes quickly from samples. For example, says Dionex, a 10-g sample typically would require 15 mL of solvent and about 12 min to complete the extraction. The ASE 200 accommodates 11-, 22-, and33-mL extraction cells; dual sample carousels hold up to 24 samples. The system meets the requirements of EPA's proposed Method 3545 for pesticides and herbicides. EPA insiders say they are impressed with this technology.
Water and air analysis
Dionex's ASE 200 uses less solvent to run traditional extractions.
There are a number of systems using flow injection analysis for analyzing mercury in water, but the IMAX 2000 mercury analysis system from Columbia Analytical Instruments (Columbia, SC) is built from a unique perspective. The company is really Columbia Analytical Laboratories, an environmental testing laboratory, and, it claims, the IMAX 2000 was developed as a smarter way to deal with EPA's Method 245.2 for mercury in water. The unit features on-line sample digestion, computer control, and a dedicated detector. New instruments or methods tough enough for field measurements seem to be a regular feature at Pittcon. This year Columbia Scientific (Austin, TX) demonstrated its new transportable (38-kg) FT-IR system capable of multicomponent gas analysis down to 10-ppb levels. The Quantum 7000 comes equipped with a heated, variable pathlength gas cell, a 486 PC, and dedicated analysis software. The analyzer can make up to 12 measurements per second and can simultaneously analyze up to 20 gas components. Power is either 120 or 230 V.
Flat market HP has teamed up with PACE environmental labs to determine and demonstrate the results gained from redesigning an entire environmental laboratory.
zene, and xylenes) drops from almost 1 h for purgeand-trap to < 6 min. SPME II also is available as a stand-alone unit. As part of its effort to encourage wide use of SPME technology, Varian has made the SPME II attachable to HP's 5890 gas chromatograph.
Sample preparation EPA has begun promulgating methods based on SPE, which eliminates the large amounts of organic solvents required for liquid-liquid extractions. For this growing market, Horizon Technology (Atkinson, NH) displayed its new automated SPE-DEX 4750 system, which uses 3M's Empore 47-mm SPE disks. The 4750 is a stand-alone system designed to meet EPA's proposed Method 1664 for oil and grease and total petroleum hydrocarbons in wastewater as well as the 500 series drinking-water methods. All the steps following sample loading are automated, including rinsing the sample vial and keeping the disk from drying out. A single controller handles up to eight SPE extractor sta2 1 4 A • VOL. 29, NO. 5, 1995 / ENVIRONMENTAL SCIENCE & TECHNOLOGY
As they did last year, instrument manufacturers point to the Pacific Rim countries, Mexico, and South American countries as the biggest growth markets for environmental instruments. Most companies see "single-digit" growth rates in European Union countries and the United States. Traditionally, growth in the U.S. environmental market has been fueled by EPA promulgating rules and Congress passing new regulatory legislation. Thus, the Republicans' legislative agenda of regulatory roll-backs portends a continuing weak market. In addition, consolidation of environmental testing laboratories suggests there could be fewer customers in the future. However, innovation can create growing markets for instruments and methods. For example, H-P teamed up with Minneapolis-based PACE environmental laboratories to test H-P's instrumentation in a new facility just opened in Petaluma, CA. Varian says that it is making a major commitment to SPME. The issues of faster, smarter, and tougher instruments are likely to be long-term themes for manufacturers. Alan Newman is an associate editor on the Washington staff of ES&T.
