Detecting Trihalomethanes Using Nanoporous-Carbon Coated Surface-Acoustic-Wave Sensors. Issue 6 (7th March 2015)

• Record Type: Journal Article
• Authors: Siegal, Michael P.; Mowry, Curtis D.; Pfeifer, Kent B.; Gallis, Dorina F. Sava
• Is Part Of: Journal of the Electrochemical Society. Volume 162:Issue 6(2015)
• Page Start: B114
• Page End: B120
• Publication Date: 2015-03-07
• Subjects: Electrochemistry -- Periodicals; 541.3705
• DOI: 10.1149/2.0381506jes
• Languages: English
• ISSNs: 0013-4651

Abstract

Abstract : We study nanoporous-carbon (NPC) grown via pulsed laser deposition (PLD) as a sorbent coating on 96.5-MHz surface-acoustic-wave (SAW) devices to detect trihalomethanes (THMs), regulated byproducts from the chemical treatment of drinking water. Using both insertion-loss and isothermal-response measurements from known quantities of chloroform, the highest vapor pressure THM, we optimize the NPC mass-density at 1.05 ± 0.08 g/cm 3 by controlling the background argon pressure during PLD. Precise THM quantities in a chlorobenzene solvent are directly injected into a separation column and detected as the phase-angle shift of the SAW device output compared to the drive signal. Using optimized NPC-coated SAWs, we study the chloroform response as a function of operating temperatures ranging from 10–50°C. Finally, we demonstrate individual responses from complex mixtures of all four THMs, with masses ranging from 10–2000 ng, after gas chromatography separation. Estimates for each THM detection limit using a simple peak-height response evaluation are 4.4 ng for chloroform and 1 ng for bromoform; using an integrated-peak area response analysis improves the detection limits to 0.73 ng for chloroform and 0.003 ng bromoform.