Question

For the following analytes and situations, indicate an appropriate spectroscopic technique and briefly explain why your chose that technique.

a)     Quantitation of nitrobenzene in a solution of hexane of approximately 0.1M.

b)     Confirmation of the addition of a carbonyl group to an organic molecule.

c)     Determination of the amount of calcium in hard water that is also in the presence of magnesium.

d)     Determination of very low concentrations of anthracene in bottled water.

Answer 1

a) HPLC is good method for determination of Nitrobenzene in Hexane

b) For conformation of functional group in organic molecule IR spectroscopy is good method,particlarly for Carbonyl group it give strang band at 1715 cm-1 and also IR spectroscopy is non desdructive method.

c) To determine calcium inthe presence of magnesium in hard water Atomic Absorptio Spectroscopy is best method because different element having different absorption spectrum.So analytical line for Calcium is 422.7nm and for magnesium 285.2nm .This method lead to % to ppm level concentration detection of calcium inthe presence of magnesium.

d) Anthracene is best estimated by flourimetric method as this molecule having mulyible conjucated double bond it give best flourescenc property. It is possible to determine anthracene upto ppb level using this method