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