Analysis of Impurities in Fine Chemical Octyl-dimethyl-4- aminobenzoate Using the Agilent 1290 Infinity LC and ZORBAX RRHT and RRHD 1.8 µm Columns

Michael Woodman, Agilent Technologies, Inc.

The combined benefits are demonstrated by a separation of impurities found in a sample of octyl-dimethyl-4-aminobenzoate. The high pressure capability of the system allows the use of methanol, as well as acetonitrile, to explore the selectivity of the two solvents. At 1.5 mL/min, using a simple 2-min gradient and a 3.0 mm X 50 mm 1.8 µm column, the analysis time is only 3 min. The separation of the main components is shown in Figure 1.

Figure 1

The speed, resolution and flexibility of the system are further demonstrated by a separation of the sample using methanol or acetonitrile with low solvent consumption 2.1 mm id, 1.8 µm columns. The flow rate and gradient conditions are optimized for each solvent, to produce a gradient separation with maximum pressure of approximately 850 bar, a conservative setting for the 1200-bar capability of the Agilent 1290 Infinity LC. The separation of the main components, with the two organic solvents, is shown in Figure 2a (acetonitrile, top panel) and 2b (methanol, lower panel), where the chromatograms are zoomed to the region of peaks shown from approximately 1.2–2.5 min in Figure 1.

Figure 2

Configuration

• G4220A 1290 Infinity Binary Pump with Integrated Vacuum

Degasser

• G4226A 1290 Infinity Autosampler

• G1316C 1290 Infinity Thermostatted Column Compartment

• G4212A 1290 Infinity Diode Array Detector

Conclusions

The combined high flow and high pressure capability of the system allows one to use high efficiency columns, producing rapid separations with remarkable resolution while conserving solvent over the use of 4.6 mm id columns. Impurity detection, due to high detector sensitivity and stability, is estimated to be ? 0.01%.

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