Authors:Biljana Petanovska-Ilievska, Lenche Velkoska-Markovska, and Mirjana S. Jankulovska
Reverse-phase high-performance liquid chromatography (RP-HPLC) method for simultaneous determination of sodium benzoate and potassium sorbate in beverages was developed using high speed column. The simple and rapid reverse-phase method for quantitative determination of both preservatives was established on LiChroCART® Purospher STAR RP-18e (30 mm × 4 mm; 3 μm) column, mobile phase consisted of acetonitrile-phosphate buffer (pH = 3.5) in volume ratio of 8:92 (v/v), flow rate of 1 mL min−1, ultraviolet (UV) detection at 195 nm for sodium benzoate and 260 nm for potassium sorbate, and constant column temperature at 25 °C. Linearity, precision, accuracy, limit of quantification (LOQ), and limit of detection (LOD) were tested for method validation. Linearity range for sodium benzoate was 6.04–200.27 mg L−1 (R2 = 0.999) while, for potassium benzoate (R2 = 0.999), 12.19–406.36 mg L−1. The RSD values ≤1.03% demonstrate excellent intra-day precision. LOD for sodium benzoate and potassium sorbate was 0.004 and 0.003 mg L−1, while LOQ was 0.012 and 0.009 mg L−1, respectively. This method was applied for quantitative determination of investigated preservatives in beverages which were taken from Macedonian markets.
Authors:L. Velkoska-Markovska, B. Petanovska-Ilievska, M. S. Jankulovska, and U. Ilievski
This study presents the development and validation of a new reversed-phase high-performance liquid chromatography (RP-HPLC) method for simultaneous determination of captan, folpet, and metalaxyl residues in table grape samples with ultraviolet–diode array detection (UV–DAD). Successful separation and quantitative determination of analytes was carried out on LiChrospher 60 RP-select B (250 × 4 mm, 5 μm) analytical column. Mixture of acetonitrile–0.1% formic acid in water (65:35, v/v) was used as a mobile phase, with flow rate of 1 mL/min, constant column temperature at 25 °C, and UV detection at 220 nm. The target residues were extracted with acetone by ultrasonication, followed by a cleanup using liquid–liquid extraction (LLE) and solid-phase extraction (SPE). The obtained values for multiple correlation coefficients (R2 > 0.90), relative standard deviation (RSD) of retention times, peak areas and heights (RSD ≤ 2.25%), and recoveries ranging from 90.55% to 105.40%, with RSD of 0.02% to 5.37%, revealed that the developed method has a good linearity, precision, and accuracy for all analytes. Hence, it is suitable for routine determination of investigated fungicides in table grape samples.