title: Digital image-based flame emission spectrometry.
abstract: A digital image-based flame emission spectrometric (DIB-FES) method for the quantitative chemical analysis is proposed here for the first time. The DIB-FES method employs a webcam to capture the digital images which are associated to a radiation emitted by the analyte into an air-butane flame. Since the detection by webcam is based on the RGB (red-green-blue) colour system, a novel mathematical model was developed in order to build DIB-FES analytical curves and estimate figures of merit for the proposed method. In this approach, each image is retrieved in the three R, G and B individual components and their values were used to define a position vector in RGB three-dimensional space. The norm of this vector is then adopted as the RGB-based value (analytical response) and it has revealed to be linearly related to the analyte concentration. The feasibility of the DIB-FES method is illustrated in three applications involving the determination of lithium, sodium and calcium in anti-depressive drug, physiological serum and water, respectively. In comparison with the traditional flame emission spectrometry (trad-FES), no statistic difference has been observed between the results by applying the paired t-test at the 95% confidence level. However, the DIB-FES method has offered the largest sensitivities and precision, as well as the smallest limits of detection and quantification for the three analytes. These advantageous characteristics are attributed to the trivariate nature of the detection by webcam.
authors.affiliation: Universidade Federal da Paraíba, CCEN, Departamento de Química, Caixa Postal 5093, CEP 58051-970 João Pessoa, PB, Brazil.
authors.forename: Wellington
authors.initials: W
authors.lastname: Silva Lyra
authors.forename: Vagner Bezerra
authors.initials: VB
authors.lastname: Dos Santos
authors.forename: Amália Geiza Gama
authors.initials: AG
authors.lastname: Dionízio
authors.forename: Valdomiro Lacerda
authors.initials: VL
authors.lastname: Martins
authors.forename: Luciano Farias
authors.initials: LF
authors.lastname: Almeida
authors.forename: Edvaldo
authors.initials: E
authors.lastname: Nóbrega Gaião
authors.forename: Paulo Henrique Gonçalves Dias
authors.initials: PH
authors.lastname: Diniz
authors.forename: Edvan Cirino
authors.initials: EC
authors.lastname: Silva
authors.forename: Mário César Ugulino
authors.initials: MC
authors.lastname: Araújo
mesh_terms: D002118:Calcium / Q000032:analysis / Q000097:blood; D005240:Feasibility Studies; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008094:Lithium / Q000032:analysis / Q000097:blood; D008670:Metals / Q000032:analysis* / Q000097:blood; D004364:Pharmaceutical Preparations / Q000032:analysis; D012964:Sodium / Q000032:analysis / Q000097:blood; D013054:Spectrophotometry, Atomic / Q000379:methods*
chemical_list: D008670:Metals; D004364:Pharmaceutical Preparations; D008094:Lithium; D012964:Sodium; D002118:Calcium