Percorrer por autor "Beleza, Vitorino de Matos"
A mostrar 1 - 2 de 2
Resultados por página
Opções de ordenação
- Introduction of the parameter 'Total Organic Carbon' (TOC) as a standard for the quality control of swimming pool waterPublication . Beleza, Vitorino de Matos; Costa, Rosária Santos; Baptista, Marta Pinto; Beleza, Vitorino; Pereira, IsabelSwimmers introduce organic compounds into swimming pools due to the transferring of sweat, saliva, skin, hair, urine, feces, among other materials, to the water. Water quality control in the tank must include some chemical parameters that will quantitatively reflect the presence of these contaminants in the water. Oxidability to permanganate is included in the regulations and norms of public swimming pools in most developed countries. According to the Portuguese norm NP-731, permanganate oxidability is determined by the oxidation of organic compounds in the water by potassium permanganate in acidic conditions when boiling for 10 minutes. |n fact, this procedure detects all reductants oxidized by the essay conditions, whether organic or inorganic. To overcome these limitations, several entities suggested the determination of Total Organic Carbon (TOC). lsocyanuric acid, H30;C;N;, is used as a stabilising agent for free chlorine. In its combustion, cyanuric acid is totally oxidised, and the products of this reaction are carbon dioxide, which contributes to the TOC value, water and nitrogen. Analytical confirmation of the carbon:isocyanuric acid relationship was performed in the Centro de Estudos de Aguas laboratory, achieving ‘the value of 0.27 quite close to the theoretical relation carbon:isocyanuric acid (0.28). This relationship will help to definition of a maximum value for TOC in swimming pool water, in function of its depth.
- Optimization of HS-SPME analytical conditions using factorial design for trihalomethanes determination in swimming pool water samplesPublication . Maia, Raquel; Correia, Manuela; Brás Pereira, Isabel M.; Beleza, Vitorino de MatosTrihalomethanes (THMs) are widely referred and studied as disinfection by-products (DBPs). The THMs that are most commonly detected are chloroform (TCM), bromodichloromethane (BDCM), chlorodibromomethane (CDBM), and bromoform (TBM). Several studies regarding the determination of THMs in swimming pool water and air samples have been published. This paper reviews the most recent work in this field, with a special focus on water and air sampling, sample preparation and analytical determination methods. An experimental study has been developed in order to optimize the headspace solid-phasemicroextraction (HS-SPME) conditions of TCM, BDCM, CDBM and TBM from water samples using a 23 factorial design. An extraction temperature of 45 °C, for 25min, and a desorption time of 5 min were found to be the best conditions. Analysis was performed by gas chromatography with an electron capture detector (GC-ECD). The method was successfully applied to a set of 27 swimming pool water samples collected in the Oporto area (Portugal). TCM was the only THM detected with levels between 4.5 and 406.5 μg L−1. Four of the samples exceeded the guideline value for total THMs in swimming pool water (100 μgL−1) indicated by the Portuguese Health Authority.