Determination of benzoate, sorbate, citrate and orthophosphate ions in beverage samples using two-dimensional isotachophoretic method

Abstract

A two dimensional capillary isotachophoretic method (cITP⎯cITP) using electrolyte system consisting of leading electrolytes (LE1): [10 mM HCl + β alanine (pH 3.9) + 0.1% hydroxyethylcellulose (HEC)] and (LE2): [10 mM HCl + aminocaproic acid (pH 5.00) + 0.1% HEC], and 5 mM caproic acid as terminating electrolyte (TE) was studied. Two methods of detection, conductometric and UV Vis, were applied to the determination of selected food preservatives and additives. Practical applicability was demon strated by simultaneous determination of benzoates, sorbates, citrates and orthophosphates in 12 samples of beverages. The proposed method revealed linearity with R 2 between 0.9992 and 0.9999 for the concentration ranges: 10-100 mg/L (orthophosphate and citrate ions), 20-100 mg/L (sorbates) and 40-120 mg/L for ben zoates. The detection limits for all studied ions were from 0.85 to 3.1 mg/L whereas the quantification ones were from 2.8 to 10 mg/L. The variation coefficients for five fold analysis of all ions ranged between 0.4 and 9.1%. Obtained recoveries (from 97 to 104%) confirmed satisfactory accuracy of the proposed cITP-cITP method for the determination of tested food additives.

Recent advances in the application of capillary electromigration methods for food analysis and Foodomics

“…In general, these additives can be obtained from nature or manufactured by the chemical industry. The main food additives analyzed by CE in the period covered by this review (2013–2015) were sweeteners , preservatives , and colorants .…”

“…The developed method was applied to real food samples of juice, two soft drinks, two soy sauces, and a wine sample. Another strategy applied to increase sensitivity for preservatives detection was a two dimensional isotachophoretic cITP‐cITP method . Preservatives were detected by two methods of detection, namely conductometric and UV‐Vis.…”

Recent progress in analytical capillary isotachophoresis

“…In a similar way, orthophosphates, pyrophosphates, tripolyphosphates, and nitrites were determined in food samples with LODs about 0.15 mg/L (LE: 10 mM HCl, glycine, 0.02% HEC, pH 3.0; TE: 10 mM phosphoric acid). Jastrzębska et al reported a 2D ITP method for the determination of benzoate, sorbate, citrate, and orthophosphate in beverage samples. By using different electrolyte systems in the preseparation and analytical capillary, LODs from 0.85 to 3.1 mg/L and LOQs from 2.8 to 10 mg/L were obtained using conductivity and UV detection (LE1: 10 mM HCl, β‐alanine, 0.1% HEC, pH 3.9; LE2: 10 mM HCl, aminocaproic acid, 0.1% HEC, pH 5.00; TE: 5 mM caproic acid).…”