Zr oxide-based coloration technique for two-dimensional imaging of labile Cr(VI) using diffusive gradients in thin films.
A novel Zr oxide diffusive gradients in thin films (DGT)-based measurement technique for high-resolution imaging of labile Cr (VI) is introduced in this study. The method is based on the diphenylcarbazide coloration technique for Cr (VI) combined with computer-imaging densitometry, which provides a relation between the accumulated mass of Cr (VI) and the grayscale intensity. The Zr oxide gels show good performance in reflecting the accurate measurement of Cr (VI), independent of the effects of pH, ionic strength, and PO4(3-) concentration. Settling of the Zr-oxide gel was identified as a simple and effective method to suppress leaching of the claret-colored compound out of the gel. In addition, the optimal volume of added coloration reagent was 125 times that of the binding gel and 30min was selected as the optimal time for the chromogenic reaction. The relationship between the accumulated Cr (VI) and grayscale intensity was analyzed under the optimized conditions. The Zr oxide DGT technique could also obviously reflect the heterogeneity of sediment. Consequently, Zr oxide DGT-based coloration is certified to be a robust and suitable tool for providing effective and high-resolution information on bioavailable Cr (VI).
Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, Nanjing 210098, China.
Yu
Y
Yao
Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, Nanjing 210098, China.
Chao
C
Wang
Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, Nanjing 210098, China. Electronic address: pfWang2005@hhu.com.
Peifang
P
Wang
Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, Nanjing 210098, China.
Lingzhan
L
Miao
Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, Nanjing 210098, China.
Jun
J
Hou
Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, Nanjing 210098, China.
Teng
T
Wang
Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, Nanjing 210098, China.
Cui
C
Liu
D002857:Chromium / Q000032:analysis*; D004396:Coloring Agents / Q000737:chemistry*; D004058:Diffusion; D004784:Environmental Monitoring / Q000379:methods*; D019015:Geologic Sediments / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000032:analysis*; D015040:Zirconium / Q000737:chemistry*
D004396:Coloring Agents; D014874:Water Pollutants, Chemical; D002857:Chromium; C074702:chromium hexavalent ion; D015040:Zirconium; C028541:zirconium oxide
Coloration technique; DGT; Heterogeneity; Labile Cr (VI); Two-dimensional measurement; Zr-oxide