title: Paper-based analytical device for instrumental-free detection of thiocyanate in saliva as a biomarker of tobacco smoke exposure.
abstract: This work describes a fast and simple assay for in situ detection of thiocyanate, i.e., a biomarker of tobacco smoke exposure, in human saliva. The assay is based on the formation of an iron(III)-thiocyanate colored complex in a paper-based sensing platform and subsequent image analysis using a scanner as detection device. Experimental parameters influencing the color intensity of the complex were fully evaluated, including the selection of detection conditions, type of paper substrate, test zone dimensions and composition as well as the stability of the paper-based device. Under optimal conditions, the detection limit was 0.06mM of thiocyanate, and the repeatability, expressed as relative standard deviation, was 3%. The proposed method, characterized by its simplicity, portability and low sample consumption, was applied to the detection of thiocyanate in a series of human saliva samples. Average thiocyanate levels in the ranges 0.28-0.87mM and 0.78-4.28mM were found for non-smokers and smokers, respectively. Recovery studies were carried out at two concentration levels, showing recovery values in the range of 96.1-103.6%.
authors.affiliation: Analytical and Food Chemistry Department, Faculty of Chemistry, University of Vigo, Campus As Lagoas-Marcosende s/n, 36310 Vigo, Spain.
authors.forename: Francisco
authors.initials: F
authors.lastname: Pena-Pereira
authors.affiliation: Analytical and Food Chemistry Department, Faculty of Chemistry, University of Vigo, Campus As Lagoas-Marcosende s/n, 36310 Vigo, Spain.
authors.forename: Isela
authors.initials: I
authors.lastname: Lavilla
authors.affiliation: Analytical and Food Chemistry Department, Faculty of Chemistry, University of Vigo, Campus As Lagoas-Marcosende s/n, 36310 Vigo, Spain. Electronic address: bendicho@uvigo.es.
authors.forename: Carlos
authors.initials: C
authors.lastname: Bendicho
mesh_terms: D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000032:analysis; D019963:Clinical Chemistry Tests / Q000295:instrumentation*; D004781:Environmental Exposure / Q000032:analysis*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010209:Paper; D012463:Saliva / Q000737:chemistry*; D012906:Smoke / Q000032:analysis*; D013861:Thiocyanates / Q000032:analysis*; D055815:Young Adult
chemical_list: D015415:Biomarkers; D012906:Smoke; D013861:Thiocyanates; C031760:thiocyanate
keywords: Colorimetric analysis; In situ detection; Paper-based device; Saliva; Thiocyanate