Detection of organophosphate pesticides using a prototype liquid crystal monitor

John L. Adgate, Andrea Barteková, Peter C Raynor, J. Girard Griggs, Andrew Ryan, Bharat R. Acharya, Carla J. Volkmann, Darrin D. Most, Siyi Lai, Michael D. Bonds

Research output: Contribution to journalArticlepeer-review

25 Scopus citations


The precision and accuracy of a prototype wearable liquid crystal monitor (LCM) for the measurement of airborne organophosphate pesticide concentrations was explored in a series of laboratory experiments. LCM response to vapor-phase and aerosol diazinon was compared to concentrations obtained using a standard reference method (NIOSH 5600) at concentrations ranging from ∼8 to 108 ppb (parts per billion) over durations of 2 to 80 hours. Temperature (∼25, 30, and 35 °C) and relative humidity (15, 50, and 85%) were varied to estimate the effect of these factors on LCM performance. The LCM response to vapor phase pesticide exposure was linear for concentrations in the range of 8-20 ppb. At exposure concentrations above ∼20 ppb, however, there was a decline in monitor response and measurement precision. Elevated temperatures improved diazinon vapor-only measurement precision, while increased relative humidity reduced LCM response at the extremes of tested temperatures. Compared to vapor-only exposures, the LCM was less sensitive to diazinon aerosol concentrations, but displayed reasonable precision over a relatively large range of exposures (29 to 1190 ppb-hr). Further efforts to characterize temperature and humidity effects and improve low-end sensitivity would likely provide a portable personal exposure monitor or environmental sensor for this widely used class of pesticides.

Original languageEnglish (US)
Pages (from-to)49-55
Number of pages7
JournalJournal of Environmental Monitoring
Issue number1
StatePublished - 2009


Dive into the research topics of 'Detection of organophosphate pesticides using a prototype liquid crystal monitor'. Together they form a unique fingerprint.

Cite this