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Study on simultaneous determination of zinc and gluconate in nutritional supplements by CE-C4D

Bui Quoc Binh Pham Gia Bach Luu Thi Huyen Trang Vu Thi Nhat Le Lu Thi Minh Hien Vu Anh Phuong Do Thi Trang Nguyen Thi Ngan Nguyen Quang Huy Nguyen Viet Tru Hoang Quoc Anh Pham Thi Ngoc Mai Vu Thi Trang Nguyen Thi Anh Huong
Received: 26 May 2023
Revised: 05 Jul 2023
Accepted: 05 Jul 2023
Published: 29 Sep 2023

Article Details

How to Cite
Bui Quoc Binh, Pham Gia Bach, Luu Thi Huyen Trang, Vu Thi Nhat Le, Lu Thi Minh Hien, Vu Anh Phuong, Do Thi Trang, Nguyen Thi Ngan, Nguyen Quang Huy, Nguyen Viet Tru, Hoang Quoc Anh, Pham Thi Ngoc Mai, Vu Thi Trang, Nguyen Thi Anh Huong. "Study on simultaneous determination of zinc and gluconate in nutritional supplements by CE-C4D". Vietnam Journal of Food Control. vol. 6, no. 3, pp. 280-294, 2023

Main Article Content


Nutritional supplements providing bioavailable essential minerals, such as zinc (Zn) and magnesium (Mg), in forms of absorbable salts (e.g., gluconate, stearate, lactate, etc.) have been widely used. However, it should be noted that alongside these supplements, some excipients, including inorganic salts like zinc sulfate and magnesium sulfate, are frequently employed in pharmaceutical and nutraceutical products. Conventional analytical methods for total metal contents could not distinguish actual concentrations of bioavailable forms, suggesting the need for simultaneous analysis of both these essential minerals and their corresponding salts. In this study, we applied the capillary electrophoresis with capacitively coupled contactless conductivity detection (CE-C4D) method to simultaneously measure zinc and gluconate in nutritional supplements. The optimal analytical parameters comprise: (1) 10 mM Tris/Ace electrolyte solution at pH 5.0; (2) silica capillary with an internal diameter of 50 μm and an effective length of 30 cm; (3) separation voltage of +15 kV; (4) hydrodynamic injection mode with siphoning technique at 10 cm height and injection time of 20 s. With these conditions, limit of detections of 1.0 mg/L for zinc and 1.5 mg/L for gluconate were achieved. The method has good repeatability (RSD < 3%) and good recovery (89-103% for zinc and 88-107% for gluconate). The validated method was applied to determine zinc and gluconate concentrations in three commercially available nutritional supplement samples. To ascertain the validity of the results, cross-validation was performed using the high-performance liquid chromatography with photodiode array detection (HPLCPDA) for gluconate and the inductively coupled plasma optical emission spectrometry (ICPOES) for zinc, thereby reinforcing the reliability of the CE-C4D method.


Zinc, Gluconate, CE-C4D, nutritional supplements.


[1]. S. Frassinetti, G. L. Bronzetti, L. Caltavuturo, M. Cini and C. Della Croce, “The Role of Zinc in Life: A Review,” Journal of Environmental Pathology, Toxicology and Oncology, vol. 25, no. 3, pp. 597-610, 2006.
[2]. R. Wegmüller, F. Tay, C. Zeder, M. Brnić, R. F. Hurrell, “Zinc Absorption by Young Adults from Supplemental Zinc Citrate Is Comparable with That from Zinc Gluconate and Higher than from Zinc Oxide1, 2, 3,” The Journal of Nutrition, vol. 144, iss. 2, pp. 132-136, 2014.
[3]. H. Hsieh, K. S. Vignesh, George S. Deepe, D. Choubey, H. G. Shertzer, M. B. Genter, “Mechanistic studies of the toxicity of zinc gluconate in the olfactory neuronal cell line Odora,” Toxicology in Vitro, vol. 35, pp. 24-30, 2016.
[4]. N. M. Lowe, K. Fekete, T. Decsi, “Methods of assessment of zinc status in humans: a systematic review,” The American Journal of Clinical Nutrition, vol. 89, no. 6, pp. 2040S-2051S, 2009.
[5]. G. Gumus, H. Filik, B. Demirata, “Determination of bismuth and zinc in pharmaceuticals by first derivative UV-Visible spectrophotometry,” Analytica Chimica Acta, vol. 547, no. 1, pp. 138-143, 2005.
[6]. J. Yu, X. Zhang, Q. Lu, X. Wang, D. Sun, Y. Wang, and W. Yang, “Determination of calcium and zinc in gluconates oral solution and blood samples by liquid cathode glow discharge-atomic emission spectrometry,” Talanta, vol. 175, pp. 150-157, 2017.
[7]. Ş. Tokalıoğlu, R. Clough, M. Foulkes, and P. Worsfold, “Bioaccessibility of Cr, Cu, Fe, Mg, Mn, Mo, Se and Zn from nutritional supplements by the unified BARGE method,” Food Chemistry, vol. 150, pp. 321-327, 2014.
[8]. K. Gellein, P. M. Roos, L. Evje, O. Vesterberg, T. P. Flaten, M. Nordberg, and T. Syversen, “Separation of proteins including metallothionein in cerebrospinal fluid by size exclusion HPLC and determination of trace elements by HR-ICP-MS,” Brain Research, vol. 1174, pp. 136-142, 2007.
[9]. M. H. Lee, Y. W. Kim, and K. M. Lim, “Electrochemical evaluation of zinc and magnesium alloy coatings deposited on electrogalvanized steel by PVD,” Transactions of Nonferrous Metals Society of China, vol. 23, no. 3, pp. 876-880, 2013.
[10]. Q. Feng, L. Jin-Ming, C. Zuliang, “Simultaneous separation of nine metal ions and ammonium with nonaqueous capillary electrophoresis,” Journal of Chromatography A, vol. 1022, no. 1-2, pp. 217-221, 2004.
[11]. L. Havlíková, L. Matysová, L. Nováková, R. Hájková, P. Solich, “HPLC determination of chlorhexidine gluconate and p-chloroaniline in topical ointment,” Journal of Pharmaceutical and Biomedical Analysis, vol. 43, no. 3, pp. 1169-1173, 2007.
[12]. P. Legrand, A. Desdion, and G. Boccadifuoco, “Development of an HPLC/UV method for the evaluation of extractables and leachables in plastic: Application to a plasticpackaged calcium gluconate glucoheptonate solution,” Journal of Pharmaceutical and Biomedical Analysis, vol. 155, pp. 298-305, 2018.
[13]. K. Yoshikawa, S. Saito, and A. Sakuragawa, “Simultaneous analysis of acidulants and preservatives in food samples by using capillary zone electrophoresis with indirect UV detection,” Food Chemistry, vol. 127, no. 3, pp. 1385-1390, 2011.
[14]. Q. H. Nguyen, T. H. M. Dang, T. P.Q. Le, T. H. T. Luu, T. D. Dinh, T. K. Mai, T. M. T. Nguyen, T. A. H. Nguyen, and T. D. Mai, “Inexpensive and simple tool for quality control of nutraceutical and tonic products with capillary electrophoresis and contactless conductivity detection: Some developments in Vietnam,” Journal of Food Composition and Analysis, vol. 150, no. 104882, 2023.
[15]. T. A. H. Nguyen T. N. M. Pham, T. T. Doan, T. T. Ta, J. Saiz, T. Q. H. Nguyen, P. C. Hanser, T. M. Duc, “Simple semi-automated portable capillary electrophoresis instrument with contactless conductivity detection for the determination of β-agonists in pharmaceutical and pig-feed samples,” Journal of Chromatography A, vol. 1360, pp. 305-311, 2014.
[16]. AOAC Official Methods of Analysis, Appendix F: Guidelines for standard method performance requirements, 2012.
[17]. L. T. H. Hao, P. T. N. Mai, N. T. A. Huong, N. V. Anh, P. T. Duc, V. T. Trang, pplication of electrophoresis in food analysis. Hanoi: Science and Technology Publishing House, 2016 (in Vietnamese).