Field Analytical Chemistry & Technology最新文献

Improvements in the quantitative evaluation of atmospheric Fourier-transform infrared (FTIR) spectra, obtained in environmental monitoring by using a bistatic spectrometer setup, are presented. Preprocessing of interferograms and spectral data was carried out to improve the photometric accuracy and wave-number scale reproducibility, necessary for reliable quantitative analysis. Univariate component analysis was optimized, and a refined strategy for multivariate analysis by least squares was set up. Special procedures were developed for the determination of benzene and of small molecules with resolved rotation–vibration fine structure. Results from field measurements, which were obtained by using the implemented subroutines for univariate and multivariate spectrum evaluation, are presented and discussed. © 1999 John Wiley & Sons, Inc. Field Analyt Chem Technol 3: 141–159, 1999

A simple and rapid assay using HPLC with a tyrosinase-containing carbon paste electrode (Tyr-CPE) detector is demonstrated for the detection of phenol, p-cresol, p-methoxyphenol, and p-chlorophenol in environmental matrices. These compounds were measured in contaminated aqueous soil leachate samples or acetone/acetonitrile extracts of soil and sludge samples. The dynamic range for this assay was 2–30 ppm for phenol and p-cresol. In addition to analysis by the Tyr-CPE detector held at a reducing potential (−0.20 V), soil leachate and extracts were analyzed with the use of a carbon paste electrode (CPE) detector at oxidizing potentials (+1.0 V or +1.2 V). Compared to the CPE, the Tyr-CPE detector was very stable, showing a signal loss of only 28% over 24 h of continuous operation. In addition, the signal from the CPE degraded rapidly by 65% over 10 sequential injections, whereas the signal of the Tyr-CPE decreased by only 5% for the same number of sequential injections. Because of the minimal sample preparation for analysis of soil leachate samples, the herein-reported chromatographic system with biosensor detector could be further developed to complement portable tyrosinase enzyme electrode biosensors that detect total phenols in field settings. © 1999 John Wiley & Sons, Inc. Field Analyt Chem Technol 3: 161–169, 1999

A rapid method for estimating the total concentration of aromatic and chlorinated volatile organic compounds (VOCs) in soil with a hand-held photoionization detector (PID) was developed to assist with recently adopted protocols for sample collection and handling. The results from sample screening can be used to rank the total concentration of VOCs or to answer a simple yes or no question with regard to a single value. Coupling a rapid method for estimating the total VOC concentration with sample collection and preparation procedures that limit substrate dissaggregation and exposure complements efforts to achieve site representative estimates for vadose zone contamination and efficient laboratory analyses. © 1999 John Wiley & Sons, Inc. Field Analyt Chem Technol 3: 193–200, 1999

Transboundary influences of particulate matter less than or equal to 2.5 μm in aerodynamic diameter (PM_2.5) have been investigated in a U.S.–Mexican border region with the use of a dual fine particle sequential sampler (DFPSS) and a tapered element oscillating microbalance (TEOM®). Daily measurements of PM_2.5 were conducted with the DFPSS. Short-term variations in the concentration of PM_2.5 were measured and analyzed on site with the use of a tapered element oscillating microbalance (TEOM®) to assess episodic emissions that may have crossed the border. Fine particle carbon measurements, taken with a dichotomous sampler, and meteorological measurements were also performed. Ambient monitoring with these sampling methods was conducted for 1 year at three fixed sites very close to the border of the Lower Rio Grande Valley. Elemental tracer analyses and wind sector analyses were performed to assess transboundary influences. Ad hoc sampler comparisons were also presented. Presentation of advantages and limitations of sampling methods in this study can help establish a baseline for assessing future air quality conditions of a transboundary nature in the Valley. © 1999 John Wiley & Sons, Inc. Field Analyt Chem Technol 3: 201–217, 1999

An apparatus for the fast analysis of inorganic wood preservatives based on laser-induced plasma emission spectrometry (LIPS) has been developed. The device has been calibrated and tested under field screening conditions for application to waste wood. The analysis for the typical elements contained in common wood preservatives like copper, chromium, boron, mercury, tin, and arsenic has shown a good agreement between the results of classical chemical analysis by atomic absorption spectrometry (AAS) and laser-induced plasma emission spectrometry. Because of the internal calibration relative to the 392.0693-nm carbon II emission line (3p² P⁰−4s ²S), the influence of the humidity and the species of the wood on the results of the analysis is negligible. The present detection limits of our method for the common inorganic wood preservatives are, except for mercury, already sufficient for application in the recycling industry. Furthermore, LIPS allows a very high spatial resolution. Therefore, we were able to demonstrate on several different samples that the concentration of wood preservatives at the surface is considerably increased. © 1999 John Wiley & Sons, Inc. Field Analyt Chem Technol 3: 185–192, 1999.

A disposable sensor for the detection of polychlorinated biphenyls (PCB) in soil samples has been developed using polyclonal antibodies as recognizing element and carbon-based screen printed electrochemical electrodes as sensing element. The analysis scheme has been based on the competitive enzyme linked immunosorbent assay (ELISA) protocol. The immunochemical reaction has been carried on using an Immobilon™ membrane as the solid phase. The enzyme used for the measurement of the immunoreaction has been alkaline phosphatase whereas the electrochemical substrate was α-naphthyl phosphate. The extent of the immunochemical reaction has been monitored by means of an electrochemical product using screen-printed electrodes and differential pulse voltammetry (DPV). The screen-printed electrodes were characterized and their electrochemical performance tested. Soil samples were assayed using a simple extraction kit. A detection limit of 0.3–0.6 ng/ml in solution was achieved with the proposed method regardless of PCB mixture standard. © 1999 John Wiley & Sons, Inc. Field Analyt Chem Technol 3: 179–184, 1999

Detection and quantitation of chemicals in the environment requires Fourier-transform infrared (FTIR) instruments that are properly calibrated and tested. This calibration and testing requires field testing using matrices that are representative of actual instrument use conditions. Three methods commonly used for developing calibration files and training sets in the field are a closed optical cell or chamber, a large-scale chemical release, and a small-scale chemical release. There is no best method. The advantages and limitations of each method should be considered in evaluating field results. Proper calibration characterizes the sensitivity of an instrument, its ability to detect a component in different matrices, and the quantitative accuracy and precision of the results. © 1999 John Wiley & Sons, Inc. Field Analyt Chem Technol 3: 95–104, 1999

Quantitative chemical analysis of heated plumes with passive FT-IR remote sensing techniques is discussed and illustrated. Field spectra of a power plant plume are examined and analyzed in terms of sulfur dioxide concentration. The results are compared to known concentration values obtained from continuous emission monitors within the stack. © 1999 John Wiley & Sons, Inc. Field Analyt Chem Technol 3: 111–115, 1999

A novel open-path Fourier-transform infrared (OP-FTIR) spectrometer has been designed and constructed. The spectrometer differs from conventional OP-FTIR spectrometers in that it uses a low-resolution interferometer and a deuterated λ-alanine-doped triglycine sulfate detector. The system also incorporates separate transmitting and receiving telescopes, the mirrors of which are fabricated from spin-cast epoxy resin, and a lateral transfer hollow retroreflector. The use of these components allows for a lighter, more rugged and robust system that can easily be employed for remote sensing/continuous monitoring for both outdoor (fence line or traditional) and indoor environments. Advantages over contemporary instruments were found in weight, cost, and utility. © 1999 John Wiley & Sons, Inc. Field Analyt Chem Technol 3: 131–138, 1999