Metrohm's 815 Robotic Soliprep uses sodium hydroxide solution to titrate benzbromaron, one of the main uricosuric drugs.
This is an inexpensive alternative to LC-MS and GC-MS methods.
The 815 Robotic Soliprep weighs a defined number of tablets into the sample vessel.
After positioning the samples on the sample rack, all relevant analysis data such as weight, position and identification of the sample are entered into the sample data table of the tiamo software.
Prior to comminution, the sample is transported to the second workstation, where 60ml of methanol is added.
The Polytron comminutes the tablet for 90 seconds at 25,000rpm; comminution of three tablets requires a comminution time of 120 seconds.
Next, 10ml of water is added to the homogenised sample.
Using the 809 Titrando and the Solvotrode, benzbromaron is titrated with sodium hydroxide solution (1mol/L).
While the benzbromaron sample is being titrated, 815 Robotic Soliprep automatically cleans the external rinsing station.
Benzbromaron is a weak acid, the pKa (4.50) of which is comparable to that of acetic acid (4.75).
After loss of the hydrogen ion, the negative charge at the oxygen atom is delocalised around the ring.
The more stable the ion is, the more likely it is to form.
Hence, titration with strong bases is a convenient method for benzbromaron determination.
