The application of ultrasonic nebulization to ICP-AES analysis of metallurgical and geological samples

Barnardt, C. A. (Cornelius Andries) (1987)

Thesis (MSc)--University of Stellenbosch, 1987.

Thesis

ENGLISH ABSTRACT: The purpose of this project was to investigate the application of ultrasonic nebulization (with and without desolvation) to inductively coupled plasma atomic emission spectroscopy (ICP-AES) for the detection of low concentration elements in metallurgical and geological samples. The investigation included a study on the droplet sizes, the influence of desolvation on the plasma parameters and the determination of the detection limits. Many promising results were obtained in this project. The ultrasonic nebulizer has proved to be a very efficient component in ICP-AES. The results have shown the ultrasonic nebulizer is especially suited for elements at low concentration levels as the superior power of detection produced by the ultrasonic nebulizer cannot be matched by pneumatic nebulizers. It was found that desol vation is not essential for analyses, although the results have shown that even better sensitivity and therefore better powers of detection are obtainable with the use of desolvation. An important and hitherto unknown result of the desolvation investigation is the existence of an optimum desolvation temperature where the analyte emission intensity displays a maximum. A complete Simplex optimization of the whole instrument and procedure was therefore vital for optimum results. A knowledge of the influence of the solvent on the plasma parameters proved to be essential for a better understanding of the applicability of the ultrasonic nebulizer for analyses. However the ultrasonic nebulizer system developed in this project is unfortunately not quite suitable for quick routine analysis due to slow sample changeover, but certain modifications is proposed to improve the speed of analysis.

AFRIKAANSE OPSOMMING: Die doel van hierdie projek was om die toepassing van die ultrasoniese verstuiwer (met en sonder desol vasie) in induktiefgekoppelde plasma-atoomemissiespektroskopie (IGP-AES) vir die bepaling van lae konsentrasie elemente in metallurgiese en geologiese monsters te ondersoek. Die ondersoek het 'n studie van druppelgrootte, die invloed van desol vasie op plasmaparamaters en die bepaling van bepalingsgrense behels. Baie positiewe resultate is gedurende hierdie projek verkry. Die ultrasoniese verstuiwer het homself as 'n baie effektiewe komponent in die IGP-AES bewys. Die resultate het getoon dat die uitstekende gevoeligheid, en dus lae bepalingsgrense, wat II deur die ultrasoniese verstuiwer verkry is, nie deur die kommersiele pneumatiese II verstuiwers geewenaar kan word nie. Die resultate het verder getoon dat die ultrasoniese verstuiwer baie geskik is vir elemente met lae konsentrasievlakke. Alhoewel desol vasie nie noodsaaklik is nie, het die resultate getoon dat 'n beter gevoeligheid met behulp van desol vasie verkry kan word. 'n Belangrike en tot dusver 'onbekende resultaat wat verkry is tydens die desolvasieondersoek, is die bestaan van 'n optimum desolvasietemperatuur waarby die emissie-intensiteit 'n maksimum is. 'n Volledige Simplex-optimering van die hele instrument en prosedure is gevolglik noodsaaklik vir optimum resultate. Daar is bewys dat 'n kennis van die invloed van die oplosmiddel op die plasmaparameters noodsaaklik is vir 'n beter begrip van die toepasbaarheid van die ul trasoniese verstui wer vir analises. Ongelukkig is die ultrasoniese verstuiwer wat in hierdie projek ontwikkel is, nie heeltemal geskik vir roetine analises nie, as gevolg van die lang tydsverloop tussen monsteromruilings. Hierdie tekortkomings kan egter met sekere veranderings aan die apparaat oorbrug word om sodoende vimiger analise van monsters te verseker.

Please refer to this item in SUNScholar by using the following persistent URL: http://hdl.handle.net/10019.1/65924
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