Waters: "Non-natural threats" hidden in natural herbal diet pills

Foreword:

"Natural Herbal" has been slimming health food or dietary supplements (such as slimming teas, coffee) commonly used in the promotion of the highlights, but as health care products for national security increasingly stringent regulatory full, sometimes we can see in the news A certain health care product was found to be illegally added synthetic drugs. In these cases, sibutramine is a frequently added drug for violations.

Sibutramine is a drug used in the treatment of obesity, mainly to reduce the appetite, induce fever and increase energy consumption to achieve the treatment of obesity. However, its side effects are large and may cause heart disease. It requires medical advice and guidance from a professional doctor. Therefore, the illegal addition of this drug to health foods is not only a commercial fraud, but also poses a huge risk to consumers. Both the US FDA and the China Food and Drug Administration have added sibutramine as a key monitoring item for natural weight loss health products.

Due to the large variety and large number of weight-loss products on the market, the huge laboratory test volume required by this method requires a simpler and easier method than traditional mass spectrometry methods. Next, we will introduce a solution based on the Waters ACQUITY QDa mass spectrometer detector. Compared with the traditional UV detection, the detector has higher selectivity for complex samples and can improve the reliability of the analysis. It is especially suitable for the analysis of compounds with no UV absorption or weak UV absorption, eliminating the need for derivatization. Directly measure. At the same time, compared to traditional mass spectrometry systems, QDa detectors are easy to use and easy to operate, meeting the needs of large-volume inspections.

solution:

Thin layer chromatography (TLC) is an analytical grade separation technique in which the sample separation process takes place on an open stationary phase on a support such as glass or plastic. High Performance TLC (HPTLC) is a quantitative analysis technology that enables spotting, panel unwinding and analysis in a semi-automatic or fully automated manner. We connected the TLC plate directly to the mass spectrometer ion source inlet to confirm the TLC separated compound using ACQUITY QDa. The capsule contents of 200 mg “Shengyuanfang” slimming products (natural herbal products) were weighed and dissolved in 10 mL of methanol. The sample was homogenized by vortexing for 30 s and then placed in an ultrasonic water bath for 10 min at room temperature. The mixture was centrifuged at 2750 RCF for 10 min at 25 ° C, and the supernatant was collected for use as a test solution.

The sibutramine reference material purchased from Fluorochem (Derby County, UK) was formulated into a solution of 0.785 mg/mL with methanol. 5 μL of sample and 2 μL of the standard were spotted onto a HPTLC Si 60 F254, 20 × 10 cm plate using a TLC autosampler 4 and developed in a 9:1 toluene/methanol solution. The plates were derivatized and then observed under white light.

The target region was eluted directly into the ACQUITY QDa using a TLC-MS interface 2 with an elliptical eluting head in a 0.1% formic acid in acetonitrile at a flow rate of 0.5 mL/min. The ACQUITY QDa operates in electrospray positive ion mode with the following default settings: capillary voltage 0.8 kV, cone voltage 15 V, desolvation gas temperature 600 °C. Full-sweep mass spectra (continuous acquisition) in the range of 50 to 650 m/z were acquired at a sampling rate of 10.0 pts/s. The mass spectrometry data was evaluated using Empower processing. Figure 1 shows the results of QDa analysis of sibutramine standard (Figure 2, channel B) and slimming products (Figure 2, channel C) after elution by TLC plate.

Figure 1. Empower mass spectrometry confirmation results.

Figure 2. HPTLC plate: A. blank, B. sibutramine ( standard) , C. weight loss product.