The preparation of standards, also referred to as reference samples, of known concentrations is a frequently used procedure in most analytical laboratories. Internal or external standards with ...

The choice of dilution schemes can minimize solution preparation errors. Most analytical procedures rely on the accurate preparation of reference standard solutions. It is common practice to prepare ...

It is often essential to test the calibration, setting and working of either old or new spectrophotometers. Generally, this is carried out by the standard plastic, gelatine or glass filters supplied ...