The established method for determination of
Phosphoric Acid in cola beverages uses the “molybdenum blue”
analysis. This spectrophotometric method is not however rapid.
An Ion Chromatography method was developed,
in our applications laboratory, which is both rapid and accurate.
The Cecil CE4715 suppressor was used to reduce background conductivity.
This improved sensitivity with reduced noise and drift. The reduction
was from about 500µS/cm to 20µS/cm. The flow rate of
the eluent: 2 mM Na2CO3 / NaHCO3 buffer, was 1.3mL/min with a 7
micron anion column. The column oven and cell were both at 45ºC.
The determination of Phosphoric
acid in a cola drink, as shown above, required under 5 minutes using
a flow rate of 1.3 mL / min.
Versatility
The modular design of the system leads
to complete versatility through interchange of modules. For
methods requiring the use of a UV/Visible detector, the conductivity
detector is easily replaced by the CE4300 variable wavelength
detector, or the fast scanning DAD WaveQuest detector as shown
in the photograph.
