title: Simultaneous determination of benzene and phenol in heat transfer fluid by head-space gas chromatography hyphenated with ion mobility spectrometry.
abstract: The quantitative determination of some compounds such as benzene and phenol in a complex matrix by ion mobility spectrometry (IMS) can be a difficult task, due to the influence of other components present in the matrix and the chemical properties of both compounds, such as their high volatility and low proton affinity. Monitoring of these compounds in a heat transfer fluid (HTF) is essential to check the correct working of a thermosolar plant and for safety and environmental reasons. Benzene and phenol, among other compounds, are produced when HTF is exposed to high temperatures in continuous cycles and their presence can decrease the efficiency of HTF. For the first time, a headspace module coupled to a gas chromatography column in combination with an IMS (with a tritium ionization source) has been optimized and fully validated to simultaneously quantify benzene and phenol in HTF. The limit of detection (LOD) and limit of quantification (LOQ) achieved with the method proposed were 0.011 and 0.038 g L(-1) and 0.004 and 0.014 g L(-1) for benzene and phenol respectively. The precision of the method was evaluated in terms of repeatability and reproducibility with all values lower than 9.2% and 13.3%, respectively. Results demonstrated that benzene and phenol were generated in the HTF heating process, and its concentration increased with heating time (approximately 483 h). The average concentration values for benzene and phenol in degraded HTF samples were not significantly different to values obtained using a gas chromatography-flame ionization detector instrument. Therefore, IMS is a promising technique for in-field quality control of HTF in a thermosolar plant due to its speed, versatility, sensitivity and selectivity to quantify these degradation compounds.
authors.affiliation: Department of Analytical Chemistry, Annex C-3 Building, Campus of Rabanales, Institute of Fine Chemistry and Nanochemistry, University of Córdoba, 14071 Córdoba, Spain.
authors.forename: L
authors.initials: L
authors.lastname: Criado-García
authors.affiliation: Department of Analytical Chemistry, Annex C-3 Building, Campus of Rabanales, Institute of Fine Chemistry and Nanochemistry, University of Córdoba, 14071 Córdoba, Spain.
authors.forename: R
authors.initials: R
authors.lastname: Garrido-Delgado
authors.affiliation: Department of Analytical Chemistry, Annex C-3 Building, Campus of Rabanales, Institute of Fine Chemistry and Nanochemistry, University of Córdoba, 14071 Córdoba, Spain.
authors.forename: L
authors.initials: L
authors.lastname: Arce
authors.affiliation: Magtel S.A., Gabriel Ramos Bejarano 114, P. I. Las Quemadas, 14014 Córdoba, Spain.
authors.forename: F
authors.initials: F
authors.lastname: López
authors.affiliation: TSK electrónica y electricidad S.A., Avda. Byron 220, P. C. Tecnológico, 33203 Gijón, Spain.
authors.forename: R
authors.initials: R
authors.lastname: Peón
authors.affiliation: Department of Analytical Chemistry, Annex C-3 Building, Campus of Rabanales, Institute of Fine Chemistry and Nanochemistry, University of Córdoba, 14071 Córdoba, Spain. Electronic address: qa1meobj@uco.es.
authors.forename: M
authors.initials: M
authors.lastname: Valcárcel
keywords: Benzene; Heat transfer fluid; Ion mobility spectrometry; Phenol; Quality control