Method development for the determination of seven ginsenosides in three Panax ginseng reference materials via liquid chromatography with tandem mass spectrometry.

A new liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for the analysis of ginsenosides in three Panax ginseng reference materials (RMs). Extraction procedures were optimized to recover neutral and malonyl-ginsenosides using a methanol-water extraction under basic conditions. Optimized mass fragmentation transitions were obtained for the development of a multiple reaction monitoring (MRM) detection method with electrospray ionization in negative and positive ion mode. Mass fraction values were determined for ginsenosides Rb1, Rb2, Rc, Rd, Re, Rf, and Rg1 in the three ginseng materials (rhizomes, extract, and an oral dosage form). Quantitation of these seven compounds was accomplished with 4-methylestradiol and SRM 3389 Ginsenoside Calibration Solution serving as an internal standard (IS) and calibration standards, respectively. Mass fraction values for the seven ginsenosides ranged from 1.27 mg/g to 21.42 mg/g, 3.25 mg/g to 35.81 mg/g, and 0.56 mg/g to 2.51 mg/g for SRM 3384, SRM 3385, and RM 8664, respectively.

Development of Kudzu (Pueraria Montana var. lobata) Reference Materials for the Determination of Isoflavones and Toxic Elements.

BACKGROUND: In collaboration with the Office of Dietary Supplements at the National Institutes of Health, the National Institute of Standards and Technology issued a suite of botanical matrix reference materials (RMs) and Standard Reference Material® (SRM) for determination of isoflavones and toxic elements in kudzu dietary supplement ingredients. OBJECTIVE: RM 8650 Pueraria montana var. lobata (Kudzu) Rhizome, SRM 3268 Pueraria montana var. lobata (Kudzu) Extract, and RM 8652 Kudzu-Containing Solid Oral Dosage Form were issued with values assigned for isoflavones (puerarin, daidzin, and daidzein), toxic elements (arsenic, cadmium, and lead), and selenium. METHODS: Isoflavone values were assigned using liquid chromatography with UV absorbance or mass spectrometry detection. Element values were assigned using inductively coupled plasma mass spectrometry and results from an interlaboratory comparison exercise. RESULTS: Mass fractions for puerarin were 32.2 ± 3.2 mg/g, 128 ± 13 mg/g, and 68.2 ± 6.9 mg/g in RM 8650, SRM 3268, and RM 8652, respectively. Arsenic increases from 156 ± 14 ng/g to 849 ± 83 ng/g and cadmium decreases from 348 ± 14 ng/g to 82.1 ± 4.9 ng/g from rhizome to extract. CONCLUSION: The kudzu RM/SRM suite complements previously issued soy-related SRMs with values assigned for isoflavones, which have been studied for their potential health benefits, and expands the analytical resource by providing values for puerarin, an isoflavone not found in soy. HIGHLIGHTS: The three new kudzurmaterials are for use in the determination of isoflavones, toxic elements, and selenium. For the isoflavones, these new kudzu materials provide higher levels of daidzin and daidzein than existing soy-related SRMs, and they provide a value for an isoflavone not in existing SRMs (puerarin). Toxic elements in RM 8650 and SRM 3268 provide new botanical matrixes for use by dietary supplement manufacturers for the verification of the safety of their raw materials.

Determination of Curcuminoids in Turmeric Dietary Supplements by HPLC-DAD: Multi-laboratory Study Through the NIH-ODS/NIST Quality Assurance Program.

BACKGROUND: Turmeric is a medicinal herb containing curcuminoids, used as quality markers in dietary supplements. In 2016, an AOAC First Action Official MethodSM was adopted for quantitation of curcuminoids and requires multi-laboratory reproducibility data for Final Action status. OBJECTIVE: To collect reproducibility data for the quantitation of curcuminoids in dietary supplements through the National Institutes of Health Office of Dietary Supplements/National Institute of Standards and Technology Quality Assurance Program (QAP). METHOD: Laboratories that participated in the QAP by following the Official Methods of AnalysisSM Method 2016.16, submitted data for ten turmeric products. The data were analyzed for mean, repeatability, and reproducibility standard deviations, repeatability, and reproducibility. RESULTS: The initial data collection resulted in insufficient replicates (five) for each test sample to determine reproducibility, therefore laboratories were provided additional materials resulting in an incremental data approach. For homogenous products, reproducibility for curcumin ranged from 3.4 to 10.3%, bisdemethoxycurcumin with reproducibility ranging from 6.4 to 14.8%, and demethoxycurcumin ranging from 5.6 to 9.9%. The method was unsuitable for the quantitation of curcuminoids in complex smoothie products, products containing microbeads, or tinctures based on interlaboratory variances. Recommendations were provided for future multi-laboratory studies performed through QAPs and incremental approaches. CONCLUSIONS: Method 2016.16 is suitable for the quantitation of curcuminoids and should be adopted for Final Action status for single and multi-ingredient dietary supplements containing dried roots, dried powders/extracts in bulk material, capsules, and softgels. HIGHLIGHTS: Reproducibility for Method 2016.16 was collected through a non-traditional incremental data multi-laboratory study. The method is suitable for quantitation of curcuminoids in most common dietary supplements.

Analytical Methodologies for the Determination of Organoarsenicals in Edible Marine Species: A Review.

Setting regulatory limits for arsenic in food is complicated, owing to the enormous diversity of arsenic metabolism in humans, lack of knowledge about the toxicity of these chemicals, and lack of accurate arsenic speciation data on foodstuffs. Identification and quantification of the toxic arsenic compounds are imperative to understanding the risk associated with exposure to arsenic from dietary intake, which, in turn, underscores the need for speciation analysis of the food. Arsenic speciation in seafood is challenging, owing to its existence in myriads of chemical forms and oxidation states. Interconversions occurring between chemical forms, matrix complexity, lack of standards and certified reference materials, and lack of widely accepted measurement protocols present additional challenges. This review covers the current analytical techniques for diverse arsenic species. The requirement for high-quality arsenic speciation data that is essential for establishing legislation and setting regulatory limits for arsenic in food is explored.

Organoarsenicals in Seafood: Occurrence, Dietary Exposure, Toxicity, and Risk Assessment Considerations - A Review.

Diet, especially seafood, is the main source of arsenic exposure for humans. The total arsenic content of a diet offers inadequate information for assessment of the toxicological consequences of arsenic intake, which has impeded progress in the establishment of regulatory limits for arsenic in food. Toxicity assessments are mainly based on inorganic arsenic, a well-characterized carcinogen, and arsenobetaine, the main organoarsenical in seafood. Scarcity of toxicity data for organoarsenicals, and the predominance of arsenobetaine as an organic arsenic species in seafood, has led to the assumption of their nontoxicity. Recent toxicokinetic studies show that some organoarsenicals are bioaccessible and cytotoxic with demonstrated toxicities like that of pernicious trivalent inorganic arsenic, underpinning the need for speciation analysis. The need to investigate and compare the bioavailability, metabolic transformation, and elimination from the body of organoarsenicals to the well-established physiological consequences of inorganic arsenic and arsenobetaine exposure is apparent. This review provides an overview of the occurrence and assessment of human exposure to arsenic toxicity associated with the consumption of seafood.

Determination of total arsenic and hydrophilic arsenic species in seafood.

Marine organisms are vital sources of staple and functional food but are also the major dietary route of human exposure to total arsenic. We surveyed the total arsenic content and the mass fractions of hydrophilic arsenic species from five different marine food types cutting across the food chain from microalgae, macroalgae, bivalve clam, crustaceans and finfish. Total arsenic was determined using inductively coupled plasma-mass spectrometry (ICP-MS) while arsenic speciation analysis was performed using high-performance liquid chromatography (HPLC) coupled to ICP-MS as the detector. The total arsenic contents ranged from 133 ± 11 ng/g to 26,630 ± 520 ng/g. The mass fractions of inorganic arsenic (iAs), arsenobetaine (AsB), dimethylarsinic acid (DMA), and the four commonly occurring arsenosugars (AsSugars) are reported. Extractable hydrophilic arsenic species accounted for 10 % (aquacultured shrimp) to 95 % (kelp) of the total arsenic. DMA was established to be a byproduct of the decomposition of AsSugars in acid extracts of samples known to contain these species.

Characterization of triacontyl (C-30) liquid chromatographic columns.

Differences in the characteristics of seventeen commercial C-30 liquid chromatographic columns were studied for the separation of carotenoid isomers. A mixture consisting of nine xanthophyll and hydrocarbon carotenoids were separated under conditions carefully chosen to reveal changes in selectivity. The influence of the mobile phase composition, column temperature, and mobile phase flow rate were evaluated. Shape selectivity was characterized with Standard Reference Material (SRM) 869b Column Selectivity Test Mixture, for correlation with carotenoid retention behavior. Regular changes were observed across a broad spectrum of shape selectivity characteristics as indicated by SRM 869b. Better separations of carotenoid isomers were achieved with C-30 columns than were possible with C-18 columns, even after optimization of separation conditions.

Challenges in Developing Analytically Validated Laboratory-Derived Dietary Supplement Databases.

The Dietary Supplement Label Database (DSLD) is sponsored by the Office of Dietary Supplements (ODS) and the National Library of Medicine (NLM). It provides a searchable, free database of the contents of ∼65,000 supplement labels. A companion database of analytically verified product labels [the Dietary Supplement Ingredient Database (DSID)] was created by ODS, NLM, and the USDA. There are considerable challenges to populating both databases, but the DSID faces unique analytic chemistry challenges. This article describes the challenges to creating analytically verified marketplace surveys of dietary supplement (DS) product content claims for inclusion in public databases. Nutritionists and public health scientists require information on actual exposures to DS constituents because labeled content may not match labeled product content. Analytic verification of composition of DSs provides a link to actual exposure. A public database of analytically derived DS content was developed to provide more accurate estimates of dietary intake in population-based epidemiologic studies. The DSID has conducted surveys of several types of vitamin- and mineral-containing DSs. Results showing label content claims as analytically derived values are available in the current DSID. A recent pilot project explored the feasibility of adding botanical DS products to the DSID. Candidates for future botanical DSID studies will be based on sales volume, potential public health impacts, and the availability of validated analytic methods and reference materials. Databases like DSID and the DSLD are essential for researchers and clinicians to evaluate dietary ingredient intakes in population-based epidemiologic studies. Together, these databases provide a picture of the DS marketplace. The DSID provides an analytic survey of marketed DSs. However, selection of future botanical supplements for DSID evaluation involves analytic challenges. Even when appropriate resources are available, method selection and data evaluation are resource- and time-consuming.