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| Author(s): |
Allen Lopes de Barros
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | São Carlos. |
| Institution: | Universidade de São Paulo (USP). Instituto de Química de São Carlos (IQSC/BT) |
| Defense date: | 2008-10-17 |
| Examining board members: |
Ana Rita de Araujo Nogueira;
Edenir Rodrigues Pereira Filho;
Boaventura Freire dos Reis
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| Advisor: | Ana Rita de Araujo Nogueira |
| Abstract | |
A flow injection system, operated under high temperature and high pressure conditions has been evaluated concerning the dissolution of fruit juices and samples of bovine milk and blood for the determination of inorganic constituents. In this system, a high pressure liquid chromatography pump was used for the transportation of liquid samples through a stainless steel heated capillary and finally through a restrictor capillary, which has a shorter inner diameter, so that the digestion of the samples could be attained. The residual carbon contents were determined by inductively coupled plasma atomic emission spectrometry. Hydride generation flame atomic absorption spectrometry was used for selenium determinations. Different configurations for the flow system were evaluated, such as variable lengths for the restrictor and digestion capillaries. Different working pressures as well as different ways for the sample introduction were tried out, being reached an alternative that avoided the precipitation of proteins before the introduction of the samples in the system. For this purpose, a configuration in which the contact between sample and reagents occurs inside the system, with no previous mixture, was evaluated. The results indicated the viability of the system which used the confluence configuration. Although digestion efficiency of 60 % was observed for milk samples, problems related to volatilization have to be circumvented. (AU) | |