Greenness Assessment and Validation of HPLC Method for Simultaneous Determination of Resveratrol and Vitamin E in Dietary Supplements

BACKGROUND

There is an increasing interest in the use of a combination of trans-resveratrol and vitamin E in dietary supplements. Determination of the content of both components is essential for confirmation of the quality of the product.

OBJECTIVE

To establish the applicability and ensure the greenness of the previously developed high-throughput HPLC/UV method for the simultaneous determination of trans-resveratrol and alpha-tocopherol acetate (vitamin E) in dietary supplements.

METHOD

Separation was performed on RP C8 Select B chromatographic column, using acetonitrile and water in the mobile phase, with gradient elution. Full method validation was performed in accordance with ICH Q2(R1). The greenness of the method was assessed using the analytical eco-scale (AES) methodology and the analytical greenness metric (AGREE).

RESULTS

The method is selective, linear, precise, and accurate over defined concentration ranges (185-369 µg/mL of trans-resveratrol and 37-75 µg/mL of alpha-tocopherol acetate), and it has a suitable sensitivity (limits of detection and quantification are 7.7 and 23.3 µg/mL for resveratrol and 2.6 and 7.8 µg/mL for tocopherol acetate, respectively). The obtained analytical eco-scale score of 77 and the pale green AGREE pictogram with an overall score of 0.61 confirm the method's greenness.

CONCLUSIONS

The sensitivity and selectivity of the method, its short analysis time (7 min), the low negative environmental impact, and the simple sample preparation make the method readily applicable to inline quality control procedures.

HIGHLIGHTS

A method for simultaneously analyzing vitamin E and resveratrol in dietary supplements is presented. The method is rapid, includes a simple sample preparation procedure, and has a low environmental impact.

Development, Validation, and Application of a Novel Method for the Analysis of Vitamin E Acetate and Other Tocopherols in Aerosol Emissions of E-Cigarettes, or Vaping Products Associated With Lung Injury

E-cigarette, or vaping, product (EVP) use has increased dramatically in the United States over the last 4 years, particularly in youth and young adults. Little information is available on the chemical contents of these products. Typically, EVPs contain an active ingredient such as nicotine, CBD, or THC dissolved in a suitable solvent that facilitates aerosol generation. One EVP solvent, vitamin E acetate (VEA), has been measured in EVP liquids associated with lung injury. However, no validated analytical methods for measuring VEA in the aerosol from these devices was previously available. Therefore, we developed a high throughput isotope dilution LC-MS/MS method to simultaneously measure VEA and three other related tocopherols in aerosolized EVP samples. The assay was precise, with VEA repeatability ranging from 4.0 to 8.3% and intermediate precision ranging from 2.5 to 6.7%. Similar precision was obtained for the three other tocopherols measured. The LODs for the four analytes ranged from 8.85 × 10⁻⁶ to 2.28 × 10⁻⁵ μg analyte per mL of aerosol puff volume, and calibration curves were linear (R² > 0.99). This method was used to analyze aerosol emissions of 147 EVPs associated with EVALI case patients. We detected VEA in 46% of the case-associated EVPs with a range of 1.87 × 10⁻⁴–74.1 µg per mL of aerosol puff volume and mean of 25.1 µg per mL of aerosol puff volume. Macro-levels of VEA (>0.1% w/w total aerosol particulate matter) were not detected in nicotine or cannabidiol (CBD) products; conversely 71% of the EVALI associated tetrahydrocannabinol (THC) products contained macro-levels of VEA. Trace levels of other tocopherol isoforms were detected at lower rates and concentrations (α-tocopherol: 41% detected, mean 0.095 µg analyte per mL of aerosol puff volume; γ-tocopherol: 5% detected, mean 0.0193 µg analyte per mL of aerosol puff volume; δ-tocopherol: not detected). Our results indicate that VEA can be efficiently transferred to aerosol by EVALI-associated EVPs vaped using a standardized protocol.