200 likes | 220 Views
The Separation of Beryllium from Spectral Interfering Elements in Inductively Coupled Plasma – Atomic Emission Spectroscopic Analysis. Daniel R. McAlister and E. Philip Horwitz PG Research Foundation, Inc. 8205 S Cass Avenue, Suite 109 Darien, IL 60561. Problems with Current Method.
E N D
The Separation of Beryllium from Spectral Interfering Elements in Inductively Coupled Plasma – Atomic Emission Spectroscopic Analysis Daniel R. McAlister and E. Philip Horwitz PG Research Foundation, Inc. 8205 S Cass Avenue, Suite 109 Darien, IL 60561
Problems with Current Method Interfering elements in the AES spectrum of Beryllium Beryllium lines very intense method is very sensitive for the determination of beryllium Interfering lines from other elements could lead to false positives.
Uptake of Selected Elements on Dipex Resin Several EXC materials evaluated Dipex offered the most promising beryllium retention characteristics
Uptake of Selected Elements on Dipex Resin Single column should remove all ICP-AES interferences Load pH 2-4 Rinse 0.2 M HNO3 Strip Be with 4 M HNO3 Potential for 2-10 x concentration of Be depending on sample size
Uptake of Selected Elements on Dipex Resin Resin selective for Be over other alkaline earth metal ions Ca and Mg common matrix impurities
Uptake of Selected Elements on Dipex Resin Fe(III) strongly retained Al(III) and Pb(II) have similar retention to Be(II) Cu(II) more weakly retained Large amounts of Fe(III) could interfere with Be(II) uptake
Uptake of Selected Elements on Dipex Resin Resin selectively retains Be(II) over most other divalent metal ions Be(II) can be separated from samples containing large quantities of divalent metal ion impurities
Proposed Method for Beryllium Purification Prepare samples as before (Digest with H2SO4/H2O2, dilute with HNO3) Neutralize samples to pH 1-2 with sodium aceate Buffers to maximum pH of 4.5 Monitor pH with methyl violet or crystal violet or pH strip pH Range over which separation is effective
Simulated Sample Results Successfully separated Be from samples digested with H2SO4/H2O2 Several different digested methods employed in Be analyses (HCl, H2SO4, HNO3, HF, H2O2, HClO4) High levels of impurities
Uptake of Selected Metal Ions on LN2 and LN3 Resins U(VI), Th(IV), Ti(IV) retained from all [HNO3] LN2: Strongly retains Fe(III) LN3: Be not retained from pH < 2 Choice of LN2/LN3 depends on desired operating conditions and amount of Fe in samples
Effect of Large Quantities of Uranium LN2 and LN3 Resins effectively increase the capacity for Uranium With LN2, the GC remains connected through the load, rinse and strip With LN3, the GC can be removed following the rinse
Conclusions Efficient, Reliable method for purifying Be from all ICP-AES spectral interfering elements has been found using a single column Method is compatible with current monitoring and sample digestion methods Method is robust and performs over a wide pH range Inserting a LN2 or LN3 Resin guard column increases U capacity without changing the chemistry or significantly decreasing Be yields. Working to develop methods to isolate Be from high levels of other impurities