Abstract: A UV-Vis spectrophotometer is simple, quick and low cost analytical technique used for the qualitative and quantitative determination of solutes (190 - 800 nm wavelength in the electromagnetic radiation) in both vapour and liquid phase. Depending on the nature of the chromophore, auxochrome, the conjugation, unsaturation properties, steric hindrance, concentration, pH and temperature of the solute and the polarity difference of solvents as well as the interaction of solute-solvent; the intensity, shape and position of maximum electronic absorption spectra of benzene and paranitroaniline influenced in UV/Vis spectroscopy measurement. The main focus of this study were (1) To optimize the working range of plastic and quartz cuvette and the effect of slit width in the spectrum of vapour phase of benzene (2) To determine the interaction effects of benzene with acetonitrile and cyclohexane, and paranitroaniline with water and cyclohexane. Plastic and quartz cuvette optimum working ranges from 300 -800 nm and above 250 nm respectively. The vapour phase with slit width of 0.1 nm and 2 nm and liquid phase in polar (acetonitrile) and non-polar (cyclohexane) of benzene maximum electronic absorption spectrum is observed at 254 nm. In the vapour phase of benzene using 2 nm slit width resolves the smooth spectrum, well resolved and high intensity as compared with 0.1nm slit width. The higher peak and vibration peak in liquid phase of benzene well resolved as compared to vapour phase. In the case of paranitroaniline, the maximum electronic absorption at 380nm shows a bathochromic shift (in water due to dipole-dipole interaction of PNA and water) and at 320nm which shows a hypsochromic shift (in cyclohexane since dipole-induced dipole interaction of PNA and cyclohexane). Therefore, as indicated in benzene and PNA the interaction of solvents matters the shape, position and intensity of maximum absorption spectra in UV/Vis spectroscopy.Abstract: A UV-Vis spectrophotometer is simple, quick and low cost analytical technique used for the qualitative and quantitative determination of solutes (190 - 800 nm wavelength in the electromagnetic radiation) in both vapour and liquid phase. Depending on the nature of the chromophore, auxochrome, the conjugation, unsaturation properties, steric hindranc...Show More
