Pu 2089 intelligent hplc quaternary pump

The quantification of organic acids was performed using a HPLC instrument (PU-2089 Intelligent HPLC quaternary pump, UV-VIS multiwavelength detector UV 2070 Plus; Jasco Corp., Tokyo, Japan) equipped with a manual Rheodyne injector with a 20 μL loop (Rheodyne, Rohnert Park, CA, USA) and a Bio-Rad Aminex HPX-87H column with a size of 300 × 7.8 mm (Bio-Rad Laboratories, Hertfordshire, UK).
The analysis was performed in isocratic conditions at 65 °C with a rate flow of 0.6 mL/min of mobile phase H₂SO₄ 0.005 M. The UV detector was set at 210 nm. Chromatographic peaks were identified by comparing retention times with those of standards (Sigma-Aldrich, St. Louis, MO, USA) and quantification was carried out by using the external standard method.

The BA were determined after 4, 8, 24, 48, 72, and 96 h of incubation. The cultures were centrifuged at 10000 rpm for 10 min at 10°C, and the supernatants were used for BAs determination by HPLC after derivatization with dansyl-chloride (Sigma–Aldrich, Gallarate, Italy) according to Martuscelli et al. (2000) (link). The BA content was analyzed using a PU-2089 Intelligent HPLC quaternary pump, Intelligent UV–VIS multiwavelength detector UV 2070 Plus (Jasco Corporation, Tokio, Japan) and a manual Rheodyne injector equipped with a 20 μl loop (Rheodyne, Rohnert Park, CA, USA). The quantification was performed according to Tabanelli et al. (2012) (link) and the amount tyramine and 2-phenylethylamine were expressed as mg/ml by reference to a calibration curve obtained with standard solutions.

The concentration of organic acids in the samples was determined by an HPLC (PU-2089 Intelligent HPLC quaternary pump, UV-VIS multiwavelength detector UV 2070 Plus; Jasco Corp., Tokyo, Japan) and a manual Rheodyne injector with a 20 μL loop (Rheodyne, Rohnert Park, CA, United States), equipped with a Bio-Rad Aminex (Bio-Rad Laboratories, Hertfordshire, United Kingdom) HPX-87H column (300 mm × 7.8 mm). The analysis was performed in isocratic conditions, using mobile phase H₂SO₄ 0.005 M, with rate flow of 0.6 ml/min and temperature of 65°C. The UV detector was set at 210 nm. Chromatographic peaks were identified by comparing retention times with those of standards (Sigma-Aldrich, St. Louis, MO, United States) and quantification was carried out by using the external standard method.
Biogenic amines were detected and quantified according to the HPLC method reported by Bargossi et al. (2015) (link). Under these analytical conditions, the biogenic amines detected were 2-phenylethylamine, putrescine, cadaverine, histamine, tyramine, spermine, and spermidine.