A simple, rapid, and nondestructive method for the determination of betulin in the outer birch bark was developed using near infrared spectroscopy (NIRS). NIRS data of the outer birch bark collected throughout the year was preprocessed and analyzed by principal component analysis, which led to clear discrimination of the samples according to their harvest times. The reference content of betulin, a major constituent of the outer birch bark, was determined using ultra performance liquid chromatography with a diode array detector (UPLC-DAD). The optimized and validated analytical conditions of UPLC-DAD provided better separation and faster analysis time compared to a conventional HPLC method. Betulin content also showed seasonal variation and was higher in the samples collected during the summer season. Partial least squares calibration techniques were employed to estimate the relationship between the NIRS data and betulin contents. The spectral data showed high correlation coefficients (over 0.700) with betulin content. These results indicate that NIRS combined with UPLC can be used to determine the quality and to quantify the betulin content of the outer birch bark.
Bibliographical noteFunding Information:
Received 28 September 2012; accepted 24 November 2012. This work was supported by the Global Leading Technology Program of the Office of Strategic R&D Planning (OSP) funded by the Ministry of Knowledge Economy, Republic of Korea (10039321). Address correspondence to Seung Hyun Kim, College of Pharmacy, Yonsei Institute of Pharmaceutical Sciences, Yonsei University, Songdo-Dong 162-1, Yeonsu-Gu, Incheon 406-840, Korea. E-mail: email@example.com
All Science Journal Classification (ASJC) codes
- Analytical Chemistry
- Clinical Biochemistry
- Biochemistry, medical