[A study on decreasing the instrument detection limit of atomic fluorescence spectrometry (AFS-930) for Hg].
In the present study, the detection limit of atomic fluorescence spectrometry (AFS-930) was decreased to 2 ng x L(-1) (n=6) based on several optimizing modifications, including that the sub-high voltage of photomultiplier tube and the current of hollow-cathode lamp were elevated to 280 V and to 30 mA, respectively, and the height of atomization cell was set as 10 mm; In addition, the concentration of KBH4 was decreased to 0.5% (KOH 0.2%). With the optimized parameters, a good standard curve of Hg concentration versus intensity of fluorescence (If) could been obtained readily, after that, a 4-ng x L(-1)-Hg water samples was measured accurately with a little relative standard deviation (RSD) of <5%, while for approximately 2-ng x L(-1)-Hg waters the RSD varied within a wide range of 10.9%-27.2%, likely due to the absorption of Hg by polyethylene vessels used in this study and/or due to the contamination by analysis grade reagents used in this study. By using low-absorption polytetrafluoroethylene (PTFE) materials and the guaranteed reagents, the instrument detection limit was further decreased to 1 ng x L(-1) (n=10).
Yin
Xue-bin
XB
Soil and Environment Bioremediation Research Center, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China. xbyin@ustc.edu.cn
Lu
Xiao-qi
XQ
Yao
Chun-xia
CX
Song
Jing
J
Qian
Wei
W
Luo
Yong-ming
YM
Liang
You-qing
YQ
Sun
Li-guang
LG
D001894:Borohydrides / Q000737:chemistry; D002138:Calibration; D057230:Limit of Detection; D008628:Mercury / Q000032:analysis; D020959:Polyethylene / Q000737:chemistry; D013050:Spectrometry, Fluorescence / Q000295:instrumentation*; D014867:Water / Q000737:chemistry
D001894:Borohydrides; D014867:Water; C028371:potassium borohydride; D020959:Polyethylene; D008628:Mercury