Currently used acid-soluble sample decomposition, thiourea or diammonium phosphate as a matrix modifier applied graphite furnace atomic absorption spectrometry (GFAAS) can be determined directly all kinds of trace silver in geological samples; but applied to determine carbonate when rock salt trace silver matrix elements calcium and magnesium can cause interference, affect the service life of the graphite tube. In this paper, hydrochloric acid - nitric acid - hydrofluoric acid - perchloric acid soluble four samples, nitric acid extracted with ammonium oxalate (45.5 g / L) as a matrix modifier test solution of calcium, magnesium and ammonium oxalate rapid reaction a white precipitate separated, and the formation of ammonium salts medium volatile environment can significantly improve the furnace temperature ashing medium to further remove the ammonium salt, thus eliminating the influence of various matrix elements. This method is simple, the national standard material verification, measurement values and the relative standard deviation values were less than 10%, the detection limit was 0.010μg / g, precision (RSD, n = 12) of less than 1.0%. This method is not only the separation of matrix interference and emission spectrometry detection limits (0.04μg / g) than the previous one meter grating used less.
Preparation of SiC by etching quantum dot fluorescence labeling material, manufacturing process parameters on the optical properties of nitric acid and hydrofluoric acid as corrosive, dispersing and crushing gravity field cut by ultrasonic cavitation chromatography to give SiC quantum dot aqueous solutions studied . the results show that the acid reducing cleaning times, when ultrasound length of quantum dot photoluminescence peak (fluorescence intensity) of the most significant impact, while the etchant composition and ratio, high gravity factor to some extent, affected the photoluminescence intensity and emission wavelengths, while increasing the content of corrosive hydrofluoric acid component such photoluminescence peak position red shift, while ultrasound length and increase the coefficient of gravity makes SiC quantum dot photoluminescence peak position blue shift. And SiC particle erosion process-related mechanisms are discussed.
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