Field Analytical Chemistry & Technology最新文献

A new data analysis software system (Ion Fingerprint Detection^TM) has been developed to provide fast mass spectral data analysis. Methods have been developed that can provide screening to quantitative gas chromatography/mass spectrometry (GC/MS) data in 30 s to minutes. Compound selectivity is provided through a unique set of algorithms rather than GC separation. The data quality produced for volatile and semivolatile organic contaminants under fast GC/MS conditions during dynamic site investigations carried out at Hanscom Air Force Base (Bedford, MA) and Joliet Army Ammunition Plant (Joliet, IL) are discussed. More than 800 samples were analyzed in each project, with state and federal regulators accepting the data to complete remedial investigation/feasibility (RI/FS) studies. ©1999 John Wiley & Sons, Inc. Field Analyt Chem Technol 3:55–66, 1999

The nerve agents Sarin (GB) and Soman (GD) were detected at the picogram level with the use of a field-portable gas chromatograph with a surface-acoustic-wave detector (SAW). The instrument, although primarily a vapor detector, can be modified with a simple front-end thermostat attachment, which allows for small-volume liquid injections for the detection of analytes in the vapor-pressure range of 0.1–5.0 torr. A field analytical method was developed with the use of the analyte surrogates dimethyl methyl phosphonate (DMMP) and triethyl phosphate (TEP). These compounds were used as internal standards by which agents GB and GD can be detected, with the use of this liquid injection method coupled to the vapor detector. Actual tests on GB and GD were performed under the same conditions, but in a more closely monitored but less field-representative laboratory environment. GB was quantitated from a calibration plot that relates signal to mass via a conversion factor in less than 10 s. The turnaround time for the instrument between data sets was 2 min, depending on the exact parameters of the method. ©1999 John Wiley & Sons, Inc. Field Analyt Chem Technol 3:45–53, 1999

A biosensor is described for the detection of phenolic compounds in water. The biosensor was fabricated by immobilizing tyrosinase in a thin layer of Eastman AQ polymer on the surface of a screen-printed electrode. The sensitivity of the biosensor is stable for 2 months at room temperature. The biosensor exhibited good sensitivity to seven of the nine phenolic compounds tested. The limit of detection (LOD) of the biosensor to phenol, catechol, 4-ethylphenol, and p-cresol was 1.5 μg/l, 0.7 μg/l, 1.4 μg/l, and 3.52 μg/l, respectively. The average precision for these four phenols was found to be approximately 7% relative standard deviation (RSD). The correlation coefficient between the biosensor and U. S. EPA Method 420.1 was found to be 0.96 when samples of water from seven areas of the United States were spiked with phenol concentrations ranging from 0.25 to 2 mg/l and analyzed with both methods. The biosensor has the potential to reduce the sampling time and cost of analyzing phenolic compounds in the field. © 1998 John Wiley & Sons, Inc. Field Analyt Chem Technol 2: 351–361, 1998

Biochemical oxygen demand (BOD) is an important index for monitoring organic pollutants in water. The conventional standard method (5-day BOD test, BOD₅), however, is a complicated and time-consuming procedure, including a 5-day incubation, and also requires considerable experience and skill to get reproducible results. To overcome these problems, microbial biosensors allowing the rapid estimation of BOD have been developed. One such BOD sensor system has already been commercialized and another highly sensitive BOD sensor, suitable for use in environmental monitoring in situations where BOD levels are low, is now being investigated. Some examples of these novel BOD sensors are described below. © 1998 John Wiley & Sons, Inc. Field Analyt Chem Technol 2: 333–340, 1998

The development of a novel, impedance-based, fieldable biosensor system is described. The portable biosensor system uses a variety of disposable analyte-specific sensor modules, each of which can be used to quantitatively measure the presence of specific analytes. The response for each sensor is rapid, and stable readings can be obtained in less than 1 min. Initial efforts have extended the use of the biosensor system to the detection of the foodborne pathogens E. coli O157:H7 and Salmonella spp. Potential applications are expected to be broad, including possible class detection of environmental endocrine disrupters, detection of the foodborne pathogen Listeria monocytogenies, and quantitative assessment of biological warfare agents. © 1998 John Wiley & Sons, Inc. Field Analyt Chem Technol 2: 371–377, 1998

The development of cost-effective on-site methods for environmental monitoring is instrumental to managing risks posed by environmental contamination. Biosensors show the potential to complement both laboratory-based and field analytical methods for environmental monitoring. Although a wide variety of biosensors have been reported for potential environmental applications, relatively few of these have progressed into commercial markets. Advances in screening methods for areas such as toxicity, bioavailability, and multiple analytes, as well as incorporation of these devices as detectors in chromatographic systems, could possibly widen the market and allow these techniques to be more competitive. © 1998 John Wiley & Sons, Inc. Field Analyt Chem Technol 2: 317–331, 1998

A portable biosensor known as the FAST 2000, developed by the Naval Research Laboratory (NRL) and engineered by Research International, Inc., has been field tested for effectiveness in performing on-site analyses for two selected explosives, TNT and RDX. The biosensor uses antibody recognition of analyte molecules and subsequent fluorescence detection downstream to measure contaminant levels in groundwater and soil. In field trials at military bases identified by the U. S. EPA as priority Superfund cleanup sites, samples containing unknown concentrations of explosives were collected from groundwater monitoring wells at various locations and analyzed in the NRL sensor with no sample pretreatment or concentration. Test sites included the Volunteer Army Ammunition Plant, Chattanooga, TN and Umatilla Army Depot Activity, Umatilla, OR. Field samples were analyzed on-site by the portable FAST 2000, and splits were analyzed by an independent U. S. EPA-certified laboratory with the use of HPLC SW846 Method 8330. Results demonstrated that the FAST 2000 can detect explosives in environmental samples with accuracy and precision. Statistical analyses based on regression curves comparing the FAST 2000 and HPLC methods showed a high degree of correlation, with r² values between 0.86 and 0.97. The assay system required small sample volumes (150 μl/test) and samples were analyzed in less than 3 min. The sensor was quantitative, with a method detection limit (MDL) of 10 μg/l. Beyond contaminated field samples, appropriate controls, blanks, and interferents were tested in the lab for certification and validation data requirements. Results were evaluated based on accuracy, precision, cost, time, and waste generation. © 1998 John Wiley & Sons, Inc. Field Analyt Chem Technol 2: 341–350, 1998

A potentiometric enzyme biosensor for the direct measurement of organophosphate pesticides was developed. The basic element of this enzyme biosensor was a pH electrode modified with an immobilized organophosphorus hydrolase layer formed by cross-linking OPH with bovine serum albumin and glutaraldehyde. Organophosphorus hydrolase catalyzes the hydrolysis of organophosporus pesticides to release protons, the concentration of which is proportional to the amount of hydrolyzed substrate. The organophosphate enzyme biosensor had a response time of less than 3 min, a useful operating range of 0.002–0.4 mM for paraoxon and parathion, and a long-term stability of over a month when stored in pH 8.5, 1 mM HEPES + 100 mM NaCl buffer at 4 °C. The effects of various parameters, buffer concentration, pH, temperature and enzyme loading are described. © 1998 John Wiley & Sons, Inc. Field Analyt Chem Technol 2: 363–369, 1998

The rapid assessment of environmental contaminants at hazardous waste sites is of great importance when evaluating the risk to human health or the environment. Traditional site investigations take years or even decades. Rather than dictate the details of the sampling and analysis program, the dynamic work plan focuses on the decision-making structure for sampling and analysis. The framework for conducting an adaptive sampling and analysis program at Hanscom Air Force Base (Bedford, MA) is described. Dynamic site investigation results are presented in the context of the field analytical tools employed, site decisions made, and cost. The data were used to support a soil-to-groundwater risk assessment and to optimize the groundwater/treatment facility operations. © 1998 John Wiley & Sons, Inc. Field Analyt Chem Technol 2:253–265, 1998