Determinació d'anions d'interès en adoberia mitjançant cromatografia iònica

• Autores: María del Carmen Pérez Quiñones
• Directores de la Tesis: Joaquim Font Vallès (dir. tes.), Anna Bacardit Dalmases (tut. tes.)
• Lectura: En la Universitat Politècnica de Catalunya (UPC) ( España ) en 2017
• Idioma: español
• Tribunal Calificador de la Tesis: Lázaro Vicente Cremades Oliver (presid.), Sílvia Sorolla Casellas (secret.), Agustí Marsal Monje (voc.)
• Materias:
  • Química
    • Química analítica
      • Análisis cromatográfico
  • Ciencias tecnológicas
    • Ingeniería y tecnología químicas
      • Química industrial
    • Tecnología industrial
      • Ingeniería de procesos
    • Tecnología metalúrgica
• Enlaces
  • Tesis en acceso abierto en: TDX
• Resumen

  • The laboratories of the leather sector have the necessity to analyse anionic species in different samples. Although ionic chromatography is currently the best method for this analysis, until now, the processes based on it were non-existent. The purpose of this thesis is the development of innovative chromatographic methods, with an ion-exchange stationary phase and a PDA detector, to determine anions of interest in the leather industry. This study contains two blocks. The first one focuses on the determination of the anions that contribute to salinity and the second block corresponds to the quantification of traces of hexavalent chromium in leather and in leather consumer goods. (Chromium VI is determinate as chromate anion).

    The analyses of the responsible anions of salinity (chloride, nitrate, sulphate, phosphate, formate, acetate...) include two investigation lines, according to the detection system, direct or indirect UV. The direct detection does not allow the analysis of non-absorbent analytes, such as chloride and sulphate, and for that reason it is also used the indirect detection (appropriate to all anions). The mobile phases used are potassium biftalate (indirect detection) and sodium sulphate (direct detection). The methods are successfully applied to different samples: leathers, waters and chemical products.

    Up to now, the determination of traces of hexavalent chromium in leather was carried out under the ISO 17075:2007 standard, based on the classical method of the diphenylecarbazide, which has some limitations. In the second part of this thesis, an HPLC method, which allows the direct analysis of chromium (VI) of the sample without any clean up process, is developed and validated. Samples are extracted at pH 7.5-8 with a phosphate buffer, according to the method of the ISO 17075 standard. An ammonium sulphate electrolyte at pH 8 is used as mobile phase. The comparative study between the ISO 17075:2007 and the new method concludes that the HPLC method is a better alternative for determining chromium (VI). The chromatographic method shortens the procedure of the colorimetric standard, decreases the amount of work, reduces the quantity of laboratory wastes and provides more accurate results. The ionic chromatography is able to measure the chromium (VI) concentration of samples up to 3mg/kg (the limit of quantification established by the European Commission). This research has eventually led to the publication of the new standard chromatographic ISO 17075-2:2017.