Perkin elmer series 200 hplc system

HPLC analysis of anthocyanins was based on a method by Azman et al. [30 (link)]. Briefly, the mobile phase consisted of 2% (v/v) formic acid (Solvent A) and 100% (v/v) methanol (Solvent B). The gradient condition was 15% (B) at 0 min, 35% (B) at 15 min, 60% (B) at 30 min, and end at 80% (B) at 40 min. A Purospher STAR RP18 end-capped column (250 mm $\times$ 4.6 mm i.d., particle size of 5 µm, Merck, Darmstadt, Germany) in a Perkin Elmer Series 200 HPLC system (PerkinElmer Inc., Bridgeport Avenue, Shelton, CT, USA), equipped with a Perkin Elmer Series 200 UV/Vis detector, Perkin Elmer Series 200 pump, Shimadzu CTO-10A column oven with a manual injector, and Perkin Elmer Series 200 vacuum degasser. The column temperature and flow rate were set up at 30 °C and 1.0 mL/min, respectively. Notably, ethanol was removed before injection into the HPLC system. The injection volume was fixed at 20 µL and the period of analysis was 45 min. A wavelength of 520 nm was used to detect the anthocyanins.
The calibration curve for each anthocyanin was plotted against the concentrations range of 0.1–0.02 mg/mL. Table 1 shows the determination coefficient (R²), the limit of detection (LOD), and limit of quantification (LOQ), which were calculated as: $$\mathrm{L}\mathrm{O}\mathrm{D}=\frac{{3S}_a}{b} \mathrm{a}\mathrm{n}\mathrm{d} \mathrm{L}\mathrm{O}\mathrm{Q}=\frac{{10S}_a}{b}$$
where $S_a$ is the standard deviation of the response and b is the slope of the calibration curve [31 (link)].

Chromatographic analyses were performed using a PerkinElmer series 200 HPLC system (PerkinElmer, Waltham, MA, USA) comprising a quaternary LC pump, autosampler, column oven, and a UV detector. Reaction conditions, sample preparation, and analysis were performed as described by Khalife and Lupidi [4 (link)], with small modifications. Briefly, GSH was dissolved in PBS buffer and mixed with solutions of degraded TQ. After 2 min of incubation at room temperature (~22 °C), the samples were mixed with methanol (1:1, v/v) and filtered through a 0.45 mm Millipore filter. The volume injected was 20 μL. The isocratic elution on an Agilent Eclipse XDB-C18 column (3.5 µm, 150 × 4.6 mm) (Agilent Technologies, Santa Clara, CA, USA) was performed at a flow rate of 1.0 mL/min, with the mobile phase composed of water:methanol:2-propanol (50:45:5 v/v). Analyses were performed at room temperature. UV monitoring of the eluted solutions was carried out at 254 nm.