Ultrasonic energy as a tool to overcome some drawbacks in the determination of lead in brain tissue and urine of rats

• Published in: Talanta (Oxford) 2011-10, Vol.86, p.442-446
• Main Authors: Guimarães, D., Santos, J.P., Carvalho, M.L., Vale, G., Santos, H.M., Geraldes, V., Rocha, I., Capelo, J.L.
• Format: Article
• Language: English
• Subjects: Analytical chemistry; Animals; Brain; Brain Chemistry; Chemistry; Electrothermal atomization; Exact sciences and technology; Lead; Lead - chemistry; Lead - urine; Rats; Sonication - methods; Spectrometric and optical methods; Spectrophotometry, Atomic - methods; Ultrasonic; Urine
• ISSN: 0039-9140; 1873-3573
• DOI: 10.1016/j.talanta.2011.09.001

► In this study it is shown how to deal with ultrasonic extraction of lead from brain tissue and urine from rats. ► It is also shown how to handle urine samples bad preserved (i.e. formation of a precipitate). ► Finally, how to handle low amount of sample (brain tissue) with ultrasonic energy is also addressed. An ultrasonic assisted solid–liquid extraction method was developed to determine the level of lead in the brain and urine of rats. Lead was determined by electrothermal atomic absorption spectrometry with longitudinal-Zeeman background correction. Several analytical drawbacks were addressed and overcome, namely small brain sample mass and the formation of precipitate in the urine samples. Utrasonication provided by an ultrasonic probe succeeded in extracting lead from brain samples. Furthermore, it was demonstrated that the formation of a precipitate lowered the lead content in the liquid phase of the urine. Lead was back extracted from the precipitate to the liquid phase with the aid of ultrasonic energy and acidifying the urine with 10% v/v nitric acid. A microwave-assisted acid digestion protocol was used to check the completeness of the lead extraction. The within bath and between bath precision was 5% (n=9) and 7% (n=3) respectively. The limit of quantification was 1.05μgg−1 for brain samples and 2.1μgL−1 for urine samples. A total of 6 samples of urine and 12 samples of brain from control rats and another 6 samples of urine and 12 samples of brain from rats fed with tap water rich in lead acetate were used in this research. Lead levels in brain and urine from exposed rats ranged from1.9±0.2μgg−1 to 3.5±0.2μgg−1 and from 752±56μgL−1 to 60.9±1.2mgL−1 respectively. Statistically significant differences of levels of lead in brain and urine were found between exposed and non exposed rats.