Proteoglycan, a type of glycoprotein, is found in cartilages of humans and animals. They are glycosaminoglycans bound to proteins. Proteoglycan promotes skin cell growth, and production of hyaluronic acid and collagen. Proteoglycan itself also has a high-water retention capability. Using those advantages, proteoglycans are used in functional foods and cosmetics, expecting the effects such as anti-aging of skin, alleviation of arthritis symptoms, and inflammation suppression.  
In this application, proteoglycan in a commercial supplement was analyzed using OHpak SB-806M HQ, an aqueous SEC column. A good linear calibration was achieved. Analysis of a commercial supplement showed close to 100 % recovery rate, compared to the manufacturer's information provided.

Sample preparation

1. (1)Grind a supplement in a mortar to make it into powders.
2. (2)Measure 270 mg of the powder and add 15 mL of 4-M guanidine hydrochloride solution.
3. (3)Sonicate for 15 minutes and then centrifuge at 1800 x g for 10 minutes.
4. (4)Collect the supernatant. Add another 15 mL of 4-M guanidine hydrochloride to the residue and repeat the step (3). Repeat this process one more time (i.e., total of 3 times adding the 4-M guanidine hydrochloride).
5. (5)Ultrafiltrate (MW: 50,000-100,000) all collected supernatant from step (4) at 2400 x g for 30 minutes.
6. (6)Add 5 mL of water to the “proteoglycan fraction” which did not pass through the ultrafiltration membrane. Centrifuge at 1800 x g for 10 minutes. Repeat this step five times to wash the proteoglycan fraction.
7. (7)Add eluent to the proteoglycan fraction to make up the volume to 20 mL.
8. (8)Filtrate with 0.45μm membrane and use it as an injection sample.

Sample: 50 µL
Proteoglycan standard solution (0.1 mg/mL)
Pretreated supplement extract solution

1. 1.Proteoglycan