Gravimetric v/s Volumetric Solution Preparation

The demand for greater accuracy from analytical instruments has prompted the automation of sample and solution preparation based on the much more accurate ‘solvent weight’ to ‘sample weight’ basis—the gravimetric method.

The gravimetric method is inherently more accurate than the volumetric method because the tempera­ture of the solvent can be ignored. The amount of solvent contained by a volumetric flask is a function of temperature—but the weight of the solvent is not affected by temperature.

Volumetric Method Costs

• Volumetric Cost: volumetric glassware. Gravimetric systems can use any vessel.

• Volumetric Cost: wasted solvent. With the gravimetric method, any volume of a solu­tion can be prepared as easily as one litre.

• Volumetric Cost: safety. With a gravimetric closed system, exposure to spilled solvents, broken glassware and harmful solvent vapours is reduced.

• Volumetric Cost: losing laboratory integrity; misidentifying a peak in a chromatogram because the solvent was not mixed accurately. Automating preparations with the gravimetric method provides consistently accurate results.