Determination of trace selenium by solid substrate-room temperature phosphorescence enhancing method based on potassium chlorate oxidizing phenyl hydrazine-1,2-dihydroxynaphthalene-3,6-disulfonic acid system.
A new method for the determination of trace selenium based on solid substrate-room temperature phosphorimetry (SS-RTP) has been established. This method was based on the fact that in HCl-KCl buffer solution, potassium chlorate could oxidize phenyl hydrazine to form chloridize diazo-ion after being heated at 100 degrees C for 20 min, and then the diazo-ion reacted with 1,2-dihydroxynaphthalene-3,6-disulfonic acid to form red azo-compound which could emit strong room temperature phosphorescence (RTP) signal on filter paper. Selenium could catalyze potassium chlorate oxidizing the reaction between phenyl hydrazine and 1,2-dihydroxynaphthalene-3,6-disulfonic acid, which caused the sharp enhancement of SS-RTP. Under the optimum condition, the relationship between the phosphorescence emission intensity (DeltaIp) and the content of selenium obeyed Beer's law when the concentration of selenium is within the range of 1.60-320 fg spot-1 (or 0.0040-0.80 ng ml-1 with a sample volume of 0.4 microl). The regression equation of working curve can be expressed as DeltaIp=13.12+0.4839CSe(IV) (fg spot-1) (n=6), with correlation coefficient r=0.9991 and a detection limit of 0.28 fg spot-1 (corresponding to a concentration range of 7.0x10(-13) g ml-1 Se(IV), n=11). After 11-fold measurement, R.S.D. were 2.8 and 3.5% for the samples containing 0.0040 and 0.80 ng ml-1 of Se(IV), respectively. This accurate and sensitive method with good repeatability has been successfully applied to the determination of trace selenium in Chinese wolfberry and egg yolk with satisfactory results. The mechanism of the enhancement of phosphorescence was also discussed.
Liu
Jia-Ming
JM
Department of Chemistry, Zhangzhou Normal College, Zhangzhou 363000, PR China. zzsyliujiaming@163.com
Cui
Xiao-Jie
XJ
Li
Lai-Ming
LM
Fu
Geng-Min
GM
Lin
Shao-Xian
SX
Yang
Min-Lan
ML
Xu
Mei-Ying
MY
Wu
Zhi-Qun
ZQ
D000818:Animals; D002138:Calibration; D002704:Chlorates / Q000737:chemistry*; D006834:Hydrazines / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D008163:Luminescent Measurements / Q000379:methods*; D032305:Lycium / Q000737:chemistry; D009281:Naphthalenes / Q000737:chemistry*; D009282:Naphthalenesulfonates; D016877:Oxidants; D010084:Oxidation-Reduction; D010936:Plant Extracts / Q000737:chemistry; D012643:Selenium / Q000032:analysis*; D013451:Sulfonic Acids / Q000737:chemistry*; D013696:Temperature; D013997:Time Factors; D014131:Trace Elements / Q000032:analysis*
D002704:Chlorates; D006834:Hydrazines; D009281:Naphthalenes; D009282:Naphthalenesulfonates; D016877:Oxidants; D010936:Plant Extracts; D013451:Sulfonic Acids; D014131:Trace Elements; C519789:phenyl hydrazine-1,2-dihydroxynaphthalene-3,6-disulfonic acid; D012643:Selenium; C022842:chloric acid