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Separation of Alkali and Alkaline Earth Metals Test Mixture
CElixir-plus kit for cations and aliphatic amines is a valuable tool and preferable to traditional methods to separate
these compounds such as Ion Chromatography. Easy to use and reliable, save time when buffers are pre-made and quality control
tested.
Method Conditions:
Voltage: 30kV
Capillary: MicroSolvCE Bare Fused Silica, 75µm x 60cm
Injection: 5 sec @0.5psi
Run Buffer: CElixir-plus kit
Detection: Indirect UV 200nm
Polarity: Normal
Instrument: Beckman® P/ACE MDQ |
Method:
Using a Beckman P/ACE MDQ and a 75µm bare fused silica capillary, the earth metals are easily and reproducibly separated
using “inverse detection” mode. Buffers are pre-made and supplied in a kit as CElixir-plus. To avoid carry-over of
Sodium, the capillary should be rinsed between runs with a Lithium solution. If Lithium is an analyte of interest, NaOH
solution should be used instead.
Peaks:
NH4, Na, K, Li, Mg, Ca (approximately 10mg/L)
Discussion and Rationale on using Inverse Detection:
CE instruments are usually equipped with a UV detector, the problem is that the analyzed cations do not absorb sufficient
amount of the UV energy to allow photometric detection. For this reason, an indirect detection technique is used where the
supplied buffers (CElixir-plus) absorbs the UV and the analytes appear as negative peaks. The software of the CE
instruments will invert the signal to obtain a normal looking e-gram.
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