Question

difference between masking and demasking agents in analytical chemistry

Answer 1

A complexometric method based on selective masking and de-masking has been developed for the rapid determination of aluminium, lead and zinc from the same solution in glass and glass frit samples. The determination is carried out using potassium cyanide to mask zinc, and excess disodium salt of EDTA to mask lead and aluminium. The excess EDTA was titrated with standard Mn(II)SO4 solution using Erichrome Black-T as the indicator. Subsequently selective de-masking agents – triethanolamine, 2,3-dimercaptopropanol and a formaldehyde/acetone mixture – were used to determine quantities of aluminium, lead and zinc in a stepwise and selective manner.

Results

The accuracy of the method was established by analysing glass certified reference material NBS 1412. The standard deviation of the measurements, calculated by analysing five replicates of each sample, was found to be less than 1.5% for the method proposed.

Conclusion

The novelty of the method lies in its simplicity and accuracy afforded by there not being a need for a prior separation or instrumentation. The proposed method was found to be highly selective for the precise determination of aluminum, zinc and lead in the routine analysis of glass batch and allied materials.

Keywords

Inductively Couple Plasma Atomic Emission Spectroscopy

Triethanolamine

Inductively Couple Plasma Atomic Emission Spectroscopy

Glass Frit

Potassium Cyanide

Answer 2

A masking agent is a reagent used in pharmaceutical analysis which reacts with chemical species that may interfere in the analytics. In sports a masking agent is used to hide or prevent detection of a banned substance or illegal drug like anabolic steroids or stimulants in the illegal process of doping

Demasking agents are used to counteract the effect of a masking agent.