Prostar 210 pump

Sample preparation and determination of BAs in Ps samples were performed according to the method of Ben‐Gigirey, Baptista de Sousa, Juan, Villa, and Barros‐Velazquez (1999). The chromatographic analyses were carried out using a Varian ProStar HPLC system (Varian Corp.) with two ProStar 210 pumps, a ProStar 410 autosampler, a ProStar 325 UV/VIS Detector, and Galaxy software (Agilent) for data processing. For the separation of amines, a Discovery ® HS C18 column (150 × 4.6 mm, 5 µm; SupelcoTM Analytical) was used. The eluents were ammonium acetate (A) and acetonitrile (B), and the elution program consisted of a gradient system with a 0.8 ml/min flow rate. The detection wavelength was set to 254 nm, the oven temperature was 40°C, and samples were injected in 20 μl aliquots. The target compounds were identified based on their retention times in comparison with their corresponding standards.

Sample preparation and determination of BA content in pork meat samples were performed according to the method of Ben-Gigirey et al. [41 (link)], with some modifications [42 (link)]. The BAs were extracted with 0.4 mol/L perchloric acid, and dansyl chloride solution in acetonitrile (10 mg/mL) was used as a derivatisation reagent. The Varian ProStar HPLC system (Varian Corp., Palo Alto, CA, USA) was composed of two ProStar 210 pumps, a ProStar 410 autosampler, a ProStar 325 UV/VIS detector and the Galaxy software (Agilent, Santa Clara, CA, USA) for data processing. For the separation of BAs, a Discovery^® HS C18 column (150 × 4.6 mm, 5 µm; SupelcoTM Analytical, Bellefonte, PA, USA) was used. The BAs were identified based on their retention times in comparison to their corresponding standards.

The concentrations of xylose, glucose, acetic acid, xylitol, ethanol, HMF, and furfural were measured by high-performance liquid chromatography (HPLC) in the Biochemical Engineering Laboratory/UFCG. This was done in a system equipped with a ProStar 210 pump (Varian, CA, USA), a manual injector with a 20 µL loop, a ProStar 356 refractive index detector (Varian) for the sugars and alcohols, a 284 nm UV/visibleforthe aldehydes, and a Hi-Plex H stainless-steel analytical column (0.30 m × 7.7 mm; Varian). Column temperature was 60 °C; mobile phase was H₂SO₄ 0.005 mol L⁻¹, with a flow rate of 0.6 mL min⁻¹; and analysis time was 1 h [7 (link)].

The high performance liquid chromatography (HPLC) analysis was adapted from Keller et al. [43 (link)]. The chromatographic apparatus consisted of a Varian Prostar 210 pump, a Varian Prostar 410 autosampler, a Jasco FP-920 fluorescence detector set at λexc = 280 nm and λem = 460 nm, a Varian 850-MIB (Modular Interface Box) data system interface and a Galaxie chromatography data system. The separation was achieved with a C18 reversed-phase YMC-Pack ODS-AQ analytical column (250 × 4.6 mm I.D., 5 μm), fitted with a pre-column of the same stationary phase, and a 25 min isocratic run. The column temperature was set to 30 °C. The mobile phase was prepared with methanol, water and acetic acid (65:35:1, v/v/v), was filtered through a 0.2 μm membrane filter (GHP (hydrophilic polypropylene), Gelman) and degassed by sonication. The flow rate was 1.0 mL min⁻¹ and the injection volume was 50 μL. ZEA was recognized by retention times (21 min) and quantified by measuring peak areas and comparing them with a calibration curve. Two calibration curves, in mobile phase, were prepared. The first one, with ZEA concentrations from 0.8 µmol L⁻¹ to 3.1 µmol L⁻¹, was used with the detector gain set to 1000 to quantify the samples of ZEA with 3 µmol L⁻¹. The second one, with ZEA concentrations from 3.9 µmol L⁻¹ to 63 µmol L⁻¹, was used with gain set to 100 to quantify 60 µmol L⁻¹ ZEA samples.