Mid-Infrared Sensing of Organic Pollutants in Aqueous Environments

Abstract

The development of chemical sensors for monitoring the levels of organic pollutants in the aquatic environment has received a great deal of attention in recent decades. In particular, the mid-infrared (MIR) sensor based on attenuated total reflectance (ATR) is a promising analytical tool that has been used to detect a variety of hydrocarbon compounds (i.e., aromatics, alkyl halides, phenols, etc.) dissolved in water. It has been shown that under certain conditions the MIR-ATR sensor is capable of achieving detection limits in the 10–100 ppb concentration range. Since the infrared spectral features of every single organic molecule are unique, the sensor is highly selective, making it possible to distinguish between many different analytes simultaneously. This review paper discusses some of the parameters (i.e., membrane type, film thickness, conditioning) that dictate MIR-ATR sensor response. The performance of various chemoselective membranes which are used in the fabrication of the sensor will be evaluated. Some of the challenges associated with long-term environmental monitoring are also discussed.

Direct quantification of aromatic hydrocarbons in geochemical fluids with a mid-infrared attenuated total reflection sensor

“…5a, a film thickness of 8.4 lm was chosen for further studies since it displayed the most optimum analytical performance in terms of sensitivity and reproducibility. Various reports recommend that the film thickness needs to be approximately three times the infrared penetration depth to ensure optimum performance (Pejcic et al, 2009b;Lin and Li, 2010). Fig.…”

“…http://dx.doi.org/10.1016/j.orggeochem.2012.11.011 and quantification in geochemical fluids (Mizaikoff, 2003;Pejcic et al, 2009b;Gonzalvez et al, 2011). Due to its inherent selectivity the ATR-FTIR has been successfully used to detect a wide variety of organic compounds such as phenols (Yang and Cheng, 2001), caffeine (Alcudia-Leon et al, 2008), organophosphonates (Bryant et al, 2007), adamantane , alkyl halides (Acha et al, 2000;Yang and Ramesh, 2005), aromatic hydrocarbons (Karlowatz et al, 2004;Pejcic et al, 2009a;Young et al, 2011), and for the detection of oil-in-water as well as water-in-oil (Luzinova et al, 2012a,b).…”

Raman system for sensitive and selective identification of volatile organic compounds

“…Attenuated total reflection (ATR)-IR sensors have been used to measure traces of organic compounds in water, mainly for environmental applications [35][36][37][38][39][40][41][42][43]. These systems employ a thin polymer film [38,[40][41][42] or sol gel layer [39,43] to absorb organic compounds, concentrating the analyte in the evanescence sensing region, and enabling limits of detection in the low ppm and in some cases ppb range.…”

Low‐Stress Silicon Nitride Platform for Mid‐Infrared Broadband and Monolithically Integrated Microphotonics

“…[1][2][3][4][5][6][7][8] To achieve a universal mid-IR platform, the material requires broad mid-IR transparency, high nonlinearity, and the ability to be employed by very-large-scale integration (VLSI) processes. However, there is an urgent demand to move current microphotonics toward the mid-IR spectrum because it will not only increase the bandwidth of current optoelectronics but will also enable high throughput screening for on-chip spectroscopic sensing.…”