Determination of Ultra-trace Rhodium in Water Samples by Graphite Furnace Atomic Absorption Spectrometry after Cloud Point Extraction Using 2-(5-Iodo-2-Pyridylazo)-5-Dimethylaminoaniline as a Chelating Agent.
A highly sensitive method based on cloud point extraction (CPE) separation/preconcentration and graphite furnace atomic absorption spectrometry (GFAAS) detection has been developed for the determination of ultra-trace amounts of rhodium in water samples. A new reagent, 2-(5-iodo-2-pyridylazo)-5-dimethylaminoaniline (5-I-PADMA), was used as the chelating agent and the nonionic surfactant TritonX-114 was chosen as extractant. In a HAc-NaAc buffer solution at pH 5.5, Rh(III) reacts with 5-I-PADMA to form a stable chelate by heating in a boiling water bath for 10 min. Subsequently, the chelate is extracted into the surfactant phase and separated from bulk water. The factors affecting CPE were investigated. Under the optimized conditions, the calibration graph was linear in the range of 0.1-6.0 ng/mL, the detection limit was 0.023 ng/mL for rhodium and relative standard deviation was 3.67% (c= 1.0 ng/mL,n= 11)．The method has been applied to the determination of trace rhodium in water samples with satisfactory results.
School of Chemical Engineering, Xi'an University, Xi'an 710065, China. xahquan@hotmail.com.|School of Chemistry and Chemical Engineering, Yan'an Universty, Yan'an 716000, China. xahquan@hotmail.com.
Quan
Q
Han
School of Chemical Engineering, Xi'an University, Xi'an 710065, China. huoyeye@163.com.
Yanyan
Y
Huo
School of Chemistry and Chemical Engineering, Yan'an Universty, Yan'an 716000, China. wjy143@163.com.
Jiangyan
J
Wu
School of Chemical Engineering, Xi'an University, Xi'an 710065, China. hejin04c@126.com.
Yaping
Y
He
School of Chemical Engineering, Xi'an University, Xi'an 710065, China. yangxh1127@aliyun.com.
Xiaohui
X
Yang
School of Chemistry and Chemical Engineering, Yan'an Universty, Yan'an 716000, China. longer666111@163.com.
Longhu
L
Yang
D000814:Aniline Compounds / Q000737:chemistry*; D002138:Calibration; D002614:Chelating Agents / Q000737:chemistry*; D006108:Graphite / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D057230:Limit of Detection; D017830:Octoxynol; D011092:Polyethylene Glycols; D012238:Rhodium / Q000032:analysis*; D013054:Spectrophotometry, Atomic / Q000379:methods*; D013696:Temperature; D013997:Time Factors; D014874:Water Pollutants, Chemical / Q000032:analysis*
C000619275:2-(5-iodo-2-pyridylazo)-5-dimethylaminoaniline; D000814:Aniline Compounds; D002614:Chelating Agents; D014874:Water Pollutants, Chemical; D011092:Polyethylene Glycols; D006108:Graphite; D017830:Octoxynol; C010615:Nonidet P-40; D012238:Rhodium
2-(5-iodo-2-pyridylazo)-5-dimethylaminoaniline; TritonX-114; cloud point extraction; graphite furnace atomic absorption spectrometry; rhodium