RESUMO
A simple and accurate method was developed for determining silicon in gasoline using inductively coupled plasma optical emission spectroscopy (ICP-OES). For sample inroduction a Burgener nubulizer and a Cyclonic spray chamber were used. A gasoline sample was diluted with isooctane and then introduced into the cooled spray chamber of the ICP-OES. Good linearity was achieved in the silicon concentration range 0.1 - 10.0 mg x kg(-1), and the correlation coefficient was 0.999 96. The detection limit for silicon was 0.012 mg x kg(-1) and the silicon recoveries from gasoline samples were 95.8% - 98.4%, with relative standard deviations of less than 3.0% The method was proved to be simple, reliable and highly sensitive, and suitable for determining silicon in samples of motor gasoline, ethanol-gasoline and methanol-gasoline fuel mixtures those containing not more than 15% (V/V) oxygenates.
RESUMO
OBJECTIVE: To analyze the sex chromosome meiotic segregation in inv(Y) patients by fluorescence in situ hybridization (FISH). METHODS: Conventional cytogenetic procedures (GTG and CBG banding) and FISH were performed on metaphase chromosome. Three-color FISH was performed on sperm samples using a probe mixture containing CEPX, Tel Xp/Yp and Tel Xq/Yq to investigate the sex chromosome segregation of five inv(Y) (p11.1q11.2) carriers. A healthy man with normal semen parameters was used as control. RESULTS: There was no statistical difference in the abnormal sex chromosome number and recombination frequencies in each spermatozoon from the patient in comparison with that in the control. CONCLUSION: There was no apparent sex chromosome abnormality in the sperm of the inv(Y) (p11.1q11.2) carriers. Sperm-FISH allows further understanding of the sex chromosome segregation pattern and an accurate genetic counseling.