Detecting trihalomethanes using nanoporous-carbon coated surface-acoustic-wave sensors

Journal Article · Fri Mar 06 23:00:00 EST 2015 · Journal of the Electrochemical Society

DOI: https://doi.org/10.1149/2.0381506jes · OSTI ID:1235915

Siegal, Michael P. ^[1]; Mowry, Curtis D. ^[1]; Pfeifer, Kent B. ^[1]; Gallis, Dorina F. S. ^[1]

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1. Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

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/cm3 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. As a result, 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.

• Research Organization: Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)
• Sponsoring Organization: USDOE National Nuclear Security Administration (NNSA)
• Grant/Contract Number: AC04-94AL85000
• OSTI ID: 1235915
• Report Number(s): SAND--2015-20772J; 558211
• Journal Information: Journal of the Electrochemical Society, Journal Name: Journal of the Electrochemical Society Journal Issue: 6 Vol. 162; ISSN 0013-4651
• Publisher: The Electrochemical SocietyCopyright Statement
• Country of Publication: United States
• Language: English