Modern methods of instrumental analysis have evolved from the earlier classical methods which were dependent on measurement of mass or volumes. Such classical methods were time-consuming and were limited by errors both determinate and indeterminate.
Modern instrumental methods came to the aid of the analytical chemist by providing the following distinct benefits:
- Time saving – Analysis time has been reduced from several hours or days to even minutes
- Improvement in accuracy of results by elimination of errors introduced due to personal bias
- Improvement in sensitivity leading to trace analysis at ppt or even femto- mole levels. Such sensitivities could not be imagined using the conventional classical approach.
- Fast decisions in case of online analysis during manufacturing operations or deciding on viability before taking commercial decisions.
Instrumental versus Non-instrumental methods
The dividing line between instrumental and non-instrumental methods is very fine and often fades out. Even the classical methods make use of devices such as analytical balance or volumetric apparatus. It can be said that instrumental techniques involve use of electromechanical gadgets comprising of electronic components and circuits, optical elements and mechanical parts. Analytical chemists have exploited the properties of materials based on general principles of physics, chemistry, biology, computer science and engineering.
Some common material properties which have been exploited are:
- Electrical conductivity or resistance
- Absorbance or emission of electromagnetic radiation
- Phase transitions of materials due to heat absorption or liberation
- Temperature changes
- Acidity level changes in the medium
- Viscous behavior changes
The analytical scientist has been able to realize the potential benefits of instrumental analysis mainly in the last 4 to 5 decades. Over the period it has become possible to increase laboratory throughputs, achieve specific detection levels not imagined before, multicomponent analysis in single sample and trace detection of an analyte in complex sample matrices.
Modern instrumental techniques offer unlimited advantages but one should always bear in mind that basic analytical operational skills cannot be overlooked due to over dependence on instrumental techniques. Such basic skills ensure high reliability of results if required attention and care are exercised at time of sample extraction, treatment and handling during preservation prior to analysis.