RESUMO
Objective To establish the methods for direct determination of manganese in the urine by flame atom absorption spectrophotometry (AAS). Methods Manganese in the urinary samples were determined directly and the result was compared with that by acid digestion. Results The results showed a good linearity, from 0.01 to 0.80 ?g/ml, r=0.9997, y=0.001 87+0.785 3 x. For the same urinary sample, the average urinary manganese content was 0.027 ?g/ml, standard deviation was 0.000 015 ?g/ml, RSD=0.056%. The average recovery rate was 95.1%. No significant difference was seen compared with the acid digestion. Conclusion The direct determination of urinary manganese by AAS is simple, rapid, accurate and feasible.
RESUMO
Objective To explore the factors that cause fluoride level in the brick-tea produced in Ya'an region and look for the method for reducing tea fluoride.Methods Compared the fluoride content in the old leaves and new leaves from different fluoride level regions.Results The tea content in the old leaves was higher than that in the new leaves,there was no difference among the different plant areas.Conclusion The content of fluoride in tea increases as the growth time goes on.