Environmental Monitoring of Hydrocarbons:  A Chemical Sensor Perspective

Abstract

Assessing the environmental impact of organic pollutants requires reliable analytical tools that can rapidly screen them with minimal sample handling. Chemical sensors are expected to play an increasing role in environmental monitoring, and recent technological advances are certain to facilitate the application of chemical sensing devices. The search for highly selective, sensitive, low cost, stable, and robust sensors for hydrocarbons is an area of interest that is reflected by many publications on this topic. This report surveys some of the work that has been undertaken using sensors to detect hydrocarbons in the gas and liquid phase. The analytical capabilities of various sensors are compared and discussed in terms of their selectivity, sensitivity, and detection limit. It was found that the sensitivity is highly dependent on the experimental conditions used in the preparation of the sensing surface. Many sensors display acceptable sensitivity under controlled laboratory conditions; however, very few are selective enough to distinguish among several hydrocarbons in complex mixtures. Selectivity is still a challenge that is hindering the widespread application of chemical sensors for environmental monitoring of hydrocarbons and a number of strategies have been proposed to help overcome some of these problems.

An assessment of sensing technologies for the detection of clandestine methamphetamine drug laboratories

“…The transduction mechanism is intrinsically non-specific and the sensors require appropriate chemically selective material. In the case of polymer chemicapacitors, the choice of polymer can also limit the lifetime of the sensors as a result of sensing material degradation [19]. In addition, sensor drift may occur due to irreversible chemical interactions with the environment, and selectivity is an issue since polymers possess significant crosssensitivities [20].…”

Developing novel gas sensors for NO2 detection based on Ce(1-x)MXO2, {M = Ru, In} solid solutions

“…In this context, lanthanum [7], indium [10][11][12][13][14] and ruthenium [15,16], are elements that have been successfully tested as oxides for some applications like gas-sensor materials and in the present work, are added to ceria.…”

Evaluation of a PVC sensing phase for determination of chlorinated hydrocarbons in water by mid-infrared spectroscopy

“…However, some optical sensors based on midinfrared spectroscopy have been successfully applied for detection of chlorinated hydrocarbons in water. [10][11][12] Analytical methods that employ mid-infrared spectroscopy, developed for the determination of hydrocarbons in water, are based on strategies that remove water from the spectral measurement, as this compound has a wide and intense absorption band which interferes in the direct determination of many analytes. 13 These pollutants are usually present in water in very small quantities, impairing their direct detection and quantification.…”