Question

You have been given a 1 L bottle of a colourless liquid to analyze. Preliminary tests show that the sample is aqueous and upon heating to dryness a series of water-soluble salts collected on the bottom of the container. A few qualitative wet tests indicated that the sample was composed of the salts of halides (F–, Cl–, Br–, etc.), sulfate (SO42–) and ions of alkali metals (Li+, Na+, K+ etc.). The client would like you to quantitatively determine the concentration of cations and anions in the solution. Select the best method.

Options: HPLC with a UV detector

HPLC - Ion Chromatography with a conductivity detector

Gas chromtography with a conductivity detector

HPLC -Ion chromatography with a flame ionization detector

Answer 1

Given sample solution is an aqueous solution hence we can go with HPLC with ion chromatography rather than GC or just HPLC with UV.

Because GC would not be good to with high bp water as a solvent and UV may not detect alkali metals

HPLC with flam ionization detector will be able to distinguish metal cations but may not be good anions.

In case of conductivity detector we can determine all, metal ions as well as cations.

Hence best way to do the analysis is using

HPLC - Ion Chromatography with a conductivity detector.