Spectrophotometric requirements

A UV/visible-region spectrophotometer is a useful piece of back-up equipment for a residue laboratory and for certain compounds can substitute for GLC or HPLC. Colorimetric procedures are available for organophosphorus and carbamate compounds, dithiocarbamates and for certain herbicides and fungicides. These procedures are used extensively in developing countries where other facilities are limited, but they can be prone to interference and in some cases the sensitivity can be poor. A laboratory dealing with a range of compounds may find it useful to have access to a spectrophotometer, but for many laboratories it will find little use and funds can be better spent on other equipment.

Many current methods for the determination of active-ingredient content in pesticide formulations employ spectrophotometric methods although these are gradually being replaced by GLC and HPLC procedures. There is therefore still a certain requirement for a spectrophotometer for this purpose.