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BCIT Citations Collection

Determination of phenolic constituents in echinacea raw materials and dietary supplements by HPLC-UV
A collaborative study was conducted to evaluate an HPLC method for determining phenolic compounds in Echinacea spp. raw materials, powdered extracts, and tinctures. Eleven collaborating laboratories received three practice samples representing each matrix type, phenolic reference standards, eight test samples as blind duplicates, the validated analytical method, and instructions. Test samples included two raw materials, four extracts (including one in combination with astragalus and reishi), one ethanolic tincture in combination with goldenseal, and one glycerite tincture. Each material was extracted with a 60% methanol aqueous solution, separated on a C18 column, and detected at 330 nm. Results reported by laboratories for total phenolics in Echinacea roots, aerial parts, and extracts ranged from 9.5 to 62.9 mg/g with RSDR ranging from 3.64 and 7.95% and Horwitz ratio (HorRat) values ranging from 1.06 to 2.01. Total phenolics in the ethanolic tincture ranged from 4837 to 5962 μg/mL, with an RSDR of 6.35% and a HorRat value of 1.45. The glycerite tincture showed poor interlaboratory precision with a HorRat value of 3.32, an RSDR of 21.8%, and reported total phenolic values ranging from 257 to 539 μg/mL., Peer-reviewed article, Published. Received May 4, 2016; Accepted by AP May 25, 2016.
Determination of β-N-methylamino-L-alanine, N-(2-aminoethyl)glycine, and 2,4-diaminobutyric acid in food products containing cyanobacteria by ultra-performance liquid chromatography and tandem mass spectrometry
A single-laboratory validation study was completed for the determination of β-N-methylamino-L-alanine (BMAA), N-(2-aminoethyl)glycine (AEG), and 2,4-diaminobutyric acid (DAB) in bulk natural health product supplements purchased from a health food store in Canada. BMAA and its isomers were extracted with acid hydrolysis to free analytes from protein association. Acid was removed with the residue evaporated to dryness and reconstituted with derivatization using 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate (AccQ-Fluor). Chromatographic separation and detection were achieved using RP ultra-performance LC coupled to a tandem mass spectrometer operated in multiple reaction monitoring mode. Data from biological samples were evaluated for precision and accuracy across different days to ensure repeatability. Accuracy was assessed by spike recovery of biological samples using varying amino acid concentrations, with an average recovery across all samples of 108.6%. The analytical range was found to be 764-0.746 ng/mL prior to derivatization, thereby providing a linear range compatible with potentially widely varying analyte concentrations in commercial health food products. Both the U. S. Food and Drug Administration (FDA) and U. S. Pharmacopeia definitions were evaluated for determining method limits, with the FDA approach found to be most suitable having an LOD of 0.187 ng/mL and LLOQ of 0.746 ng/mL. BMAA in the collected specimens was detected at concentrations lower than 1 μg/g, while AEG and DAB were found at concentrations as high as 100 μg/g. Finding these analytes, even at low concentrations, has potential public health significance and suggests a need to screen such products prior to distribution. The method described provides a rapid, accurate, and precise method to facilitate that screening process., Peer-reviewed article, Published. Received April 15, 2015; Accepted by SG June 22, 2015.