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

Abstract

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

Nanocomposite Magnetite-Kaolin for Rh Preconcentration and Determination by Electrothermal Atomic Absorption Spectrometry

“…The detection limit (3S/N) of rhodium by the combination of the magnetic kaolin preconcentration and ETAAS was 16 pg mL -1 under the optimum conditions. The value was better, compared with the detection limits with ICP-OES (8 ng mL -1 ) 14 and the combination of the cloud point extraction and ETAAS (23 pg mL -1 ) 3 . The enrichment factor was 38.…”

“…Interferences from the coexisting elements have been described for the determination of rhodium by ETAAS. 3,4,12 Therefore, the effects of Ca, Cu, K, Mg, Mn, Ni and Pb, which are generally present as matrix elements in environmental water, on the enrichment factors for Rh were investigated. The concentration of the matrix elements was 10 3 -times larger relative to that of Rh.…”

“…Electrothermal atomic absorption spectrometry (ETAAS), namely, graphite furnace atomic absorption spectrometry (GFAAS) is very convenient and in much more general use. 3 Since the detection limit of Rh for ETAAS is not superior, 3 a preconcentration method for rhodium is needed for determining Rh for an ultratrace concentration in the environmental sample. 4 Furthermore, a preliminary separation process is often required because of matrix interferences.…”

Cloud Point Extraction Combined with Electrothermal Atomic Absorption Spectrometry

“…Snaha kvantifikovať ultrastopové prvky v environmentálnych vodách s využitím spojenia CPE a ETAAS jednoznačne dominuje. V publikovaných prácach možno nájsť analýzy environmentálnych vôd rôznej komplexity (pitné 24,26,28,38,43 , rôzne povrchové 20,22,[24][25][26]28,29,43 , podzemné 20,22,26,28 , morské 27,28 , minerálne 23,38,43 ), ale úspešne sa podarilo aplikovať vypracované CPE postupy aj na separáciu a prekoncentráciu sledovaného analytu vo vodách vypúšťaných z čističiek odpadových vôd 22 , vo vodách použitých v petrochemickom priemysle 37 alebo v odpadových vodách z domácností 37 . Aj v prípade vypracovávania CPE postupov, pri ktorých je cieľom kvantifikácia ultrastopového analytu v biologických tekutinách, potravinových vzorkách alebo v rôznych tuhých environmentálnych materiáloch, sú často vypracované postupy aplikované aj na environmentálne vody.…”

Determination of Trace Nickel in Water Samples by Graphite Furnace Atomic Absorption Spectrometry after Mixed Micelle-Mediated Cloud Point Extraction

“…Among them, O-amio pyridylazo compound has unique “N,N,N” coordination structure (all the coordinate atoms are nitrogen atom), which can only react with nitrophlic metal ions, and thus has excellent selectivity. In our previous studies, we have reported CPE methods for preconcentration of cobalt, palladium, and rhodium, using O-amio pyridylazo reagents [ 20 , 21 , 22 , 23 ]. The results of our previous studies show much promise of CPE methods using O-amio pyridylazo dyes as chelating agent for preconcentration of metals for their good selectivity and sensitivity.…”