High Resolution Analysis of Compound Danshen (Salvia Miltrorrhiza) Dropping Pills using Superficially Porous LC Columns

Introduction

Danshen (Salvia miltrorrhiza) is widely used as a traditional Chinese medicine (TCM) and remedies containing Danshen are traditionally used to treat cardiac and vascular disorders. Danshen dropping pills are a compound preparation consisting of danshen, notoginseng, borneol and other components. Because there are so many compounds in the matrix, high resolution LC methods are needed for quality control of TCM's and other natural products. The current trend is to find a unique chromatogram to be used like a fingerprint. The more peaks found, the greater the sample information.

Danshen methods include a UHPLC analysis method. Here, we developed a method on an Agilent Poroshell 120, 2.7 µm superficially porous column that could be run on an available standard LC instrument at a lower pressure than the 1.8 µm column while maintaining the high resolution and critical sample information.

Experimental

Sample preparation

Dissolve ten pills in 10 mL of water. Filter with a 0.45 µm regenerated cellulose membrane filter before injecting into the HPLC for analysis.

Figure 1: Poroshell 120 EC-C18 provides high resolution below 400 bar. Conditions: Mobile phase: A, 0.02% H3 PO4; B, 0.02% H3PO4 in ACN/water (80/20); temperature: 40 °C, Injection volume: 2 µL, detection: 280 nm.

HPLC analysis

The HPLC analysis was performed on an Agilent 1200 Rapid Resolution LC (RRLC) system.

Two columns were used: Brand W, 2.1 × 100 mm, 1.8 µm and a Poroshell 120 EC-C18, 3.0 × 100 mm, 2.7 µm.

Results and Discussion

The compound danshen dropping pill was analysed on an Agilent Poroshell 120 EC-18, 2.7 µm column and a 1.8 µm UHPLC column. All eight target compounds were separated on both columns. A comparison of the results on the Poroshell 120 EC-C18 column and the 1.8 µm column showed the Poroshell 120 EC-C18 column had several advantages for this separation. The analysis time was shorter and the peak shape was better than with the UHPLC column and the resolution was very similar for the eight target compounds. This high resolution assures the same method quality on the column with superficially porous particles. The most important advantage for chromatographers without a UHPLC was a 47% lower backpressure on the Poroshell 120 EC-C18 (287 bar) column compared to the 1.8 µm column (503 bar). The revised method can be run on any LC while a UHPLC is needed to run the same method on the 1.8 µm column.

Conclusion

Poroshell 120 columns are suitable for the complex sample analysis of a TCM, such as the danshen dropping pills, because of the high resolution achieved. The pressure on the Poroshell 120 column is about 40–50% less than on a column with totally porous sub-2 micron particles, which makes the analysis on the Poroshell 120 columns suited to a standard LC.

Agilent Technologies Inc.

2850 Centerville Road, Wilmington, Delaware 19808, USA

tel +1 800 227 9770

E-mail: info_agilent@agilent.com

Website: www.agilent.com/chem/discoverporoshell