Determination of chromium(III) picolinate in dietary supplements by flow injection - electrospray ionization - tandem mass spectrometry, using cobalt(II) picolinate as internal standard

• Published in: Talanta (Oxford) Vol. 240; p. 123161
• Main Authors: Arroyo Negrete, Missael Antonio, Wrobel, Kazimierz, Yanez Barrientos, Eunice, Corrales Escobosa, Alma Rosa, Enciso Donis, Israel, Wrobel, Katarzyna
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01-04-2022
• Subjects: Chromatography, High Pressure Liquid; Chromium; Chromium picolinate; Cobalt; Dietary Supplements; Flow injection analysis; Internal Standard; Picolinic Acids; Reproducibility of Results; Spectrometry, Mass, Electrospray Ionization; Tandem Mass Spectrometry; Chromium picolinate; Tandem mass spectrometry; Internal Standard; Flow injection analysis; Dietary Supplements
• ISSN: 0039-9140; 1873-3573
• DOI: 10.1016/j.talanta.2021.123161

In this work, a principle of flow injection analysis (FIA) was applied for sample introduction to an electrospray ionization - ion trap mass spectrometer (ESI-ITMS) with the aim to quantify chromium(III) picolinate (CrPic3) in commercial supplements by multiple reaction monitoring, and using cobalt(II) picolinate as internal standard (IS). FIA system was operated with ammonium formate 10 mmol L−1 in methanol-water (1:1, v/v) as a carrier solution at a flow rate 200 μL min−1; 100 μL injections were performed in 2-min intervals. Setting ion transitions m/z 419 → 270 and 304 → 260 for the analyte and IS, respectively, and 100 ms integration time, the method detection and quantification limits 12 ng g−1 and 40 ng g−1 of Cr (as CrPic3) in the air-dried powder. Acetonitrile extracts of the real-world samples presented varying from sample-to-sample chemical composition and IS efficiently compensated for ionization interferences. Mean results from triplicate analysis of four different supplements were obtained with relative standard deviation 0.1–4.0%, indicating acceptable precision. Trueness of the proposed FIA-ESI-ITMS/MS procedure was demonstrated by 95.8–108% percentage recoveries attained in the analysis of the CrPic3-spiked samples. For comparative purposes, total Cr was determined by ICP-MS. The quantitative results obtained indicate the necessity of analytical control of Cr(III) supplements commercially available and demonstrate that the proposed FIA-ESI-ITMS/MS procedure is well-suited for the determination of CrPic3 in such products.
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•Determination of chromium(III) picolinate in dietary supplements undertaken.•FIA system set-up for sample introduction to ESI-ITMS/MS with 30 injections per hour.•Cobalt(II) picolinate as IS allowed for elimination of ionization interferences.•Quantification performed by multiple reaction monitoring.•Accuracy demonstrated via recovery experiments and by ICP-MS analysis.