title: Gas-diffusion microextraction coupled with spectrophotometry for the determination of formaldehyde in cork agglomerates.
abstract: In this work, a simple methodology was developed for the extraction and determination of free formaldehyde content in cork agglomerate samples. For the first time, gas-diffusion microextraction was used for the extraction of volatile formaldehyde directly from samples, with simultaneous derivatization with acetylacetone (Hantzsch reaction). The absorbance of the coloured solution was read in a spectrophotometer at 412 nm. Different extraction parameters were studied and optimized (extraction temperature, sample mass, volume of acceptor solution, extraction time and concentration of derivatization reagent) by means of an asymmetric screening. The developed methodology proved to be a reliable tool for the determination of formaldehyde in cork agglomerates with the following suitable method features: low LOD (0.14 mg kg-1) and LOQ (0.47 mg kg-1), r2= 0.9994, and intraday and interday precision of 3.5 and 4.9%, respectively. The developed methodology was applied to the determination of formaldehyde in different cork agglomerate samples, and contents between 1.9 and 9.4 mg kg-1were found. Furthermore, formaldehyde was also determined by the standard method EN 717-3 for comparison purposes; no significant differences between the results of both methods were observed. Graphical abstract Representation of the GDME system and its main components.
authors.affiliation: REQUIMTE/LAQV - Departamento de Química e Bioquímica, Faculdade de Ciências da Universidade do Porto, Rua do Campo Alegre, 687, 4169-007, Porto, Portugal.
authors.forename: Pedro F
authors.initials: PF
authors.lastname: Brandão
authors.affiliation: REQUIMTE/LAQV - Departamento de Química e Bioquímica, Faculdade de Ciências da Universidade do Porto, Rua do Campo Alegre, 687, 4169-007, Porto, Portugal. rui.ramos@fc.up.pt.
authors.forename: Rui M
authors.initials: RM
authors.lastname: Ramos
authors.affiliation: REQUIMTE/LAQV - Departamento de Química e Bioquímica, Faculdade de Ciências da Universidade do Porto, Rua do Campo Alegre, 687, 4169-007, Porto, Portugal.|REQUIMTE/LAQV-ICBAS - Departamento de Clínicas Veterinárias, Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, R. Jorge de Viterbo Ferreira 228, 4050-343, Porto, Portugal.
authors.forename: Inês M
authors.initials: IM
authors.lastname: Valente
authors.affiliation: REQUIMTE/LAQV - Departamento de Química e Bioquímica, Faculdade de Ciências da Universidade do Porto, Rua do Campo Alegre, 687, 4169-007, Porto, Portugal.
authors.forename: Paulo J
authors.initials: PJ
authors.lastname: Almeida
authors.affiliation: Departamento de Química Analítica, Nutricion y Bromatologia, Facultad de Quimica, Instituto de Investigación Sanitaria de Santiago de Compostela (IDIS), Universidad de Santiago de Compostela, Avda. das Ciencias, s/n. Campus sur, 15782, Santiago de Compostela, Spain.
authors.forename: Antonia M
authors.initials: AM
authors.lastname: Carro
authors.affiliation: Departamento de Química Analítica, Nutricion y Bromatologia, Facultad de Quimica, Instituto de Investigación Sanitaria de Santiago de Compostela (IDIS), Universidad de Santiago de Compostela, Avda. das Ciencias, s/n. Campus sur, 15782, Santiago de Compostela, Spain.
authors.forename: Rosa A
authors.initials: RA
authors.lastname: Lorenzo
authors.affiliation: REQUIMTE/LAQV - Departamento de Química e Bioquímica, Faculdade de Ciências da Universidade do Porto, Rua do Campo Alegre, 687, 4169-007, Porto, Portugal.
authors.forename: José A
authors.initials: JA
authors.lastname: Rodrigues
keywords: Experimental design; Formaldehyde; Gas-diffusion microextraction; Indoor air quality; Visible spectrophotometry; Wood-based products