Ms workstation

Carbamazepine concentration in plant nutrient solutions was determined by high performance liquid chromatography (HPLC), using a Varian ProStar HPLC system (Varian ProStar 215 solvent delivery module, autosampler Prostar 410). All samples were prepared in triplicate. Plant nutrient solution samples were filtered using 0.45 μm pore size polyvinylidene fluoride filters (Rotilabo, Carl Roth) before injection. Injection volume was 40 μL. The separation was performed on a C18 ProntoSIL Spheribond ODS 2 (5 μM, 125 × 4 mm, Bischoff) column under reversed phase conditions, applying a linear gradient of eluents (buffer A: H₂O, 0.1% TFA; buffer B: acetonitrile, 0.1% TFA) and a flow rate of 1 mL/min. The gradient started with 5% B for 2.5 min, ramped up to 95% in 15 min, remained at 95% for 3.5 min, and finally ramped down to 5% in 2 min. Carbamazepine was measured at 210 nm in a photodiode array detector (Varian ProStar 335) and identified by comparison of the spectra and retention time of an authentic standard (Sigma–Aldrich). Calibration curves were constructed from a set of carbamazepine standard solutions ranging from 0.25 to 12 mg/L (1.04–50 μM). Chromatograms were analyzed using MS Workstation version 6.9.3 (Varian).

The quantification of fucoidan in purified fractions of A. nodosum extract was achieved on a Varian Prostar HPLC separation module with an integrated data system (Varian MS Workstation, version 6.9.2). The HPLC system was accompanied by an autosampler (Varian Prostar, model 450), a degasser isocratic pump, and a refractive index (RI) detector (Varian, model 350). The separation was performed at 25 °C using an ultrahydrogel™ 500 size exclusion column (7.8 × 300 mm; Waters, Herts, UK). The mobile phase consisting of ultrapure water (HPLC grade) was eluted at 0.6 mL/min in isocratic mode. The injection volume of 10 µL was kept constant for samples and standard compounds [53 (link)]. The limit of detection and the limit of quantification was found to be 0.003 mg/ml and 0.009 mg/mL, respectively. Meanwhile, the standard error for the method was 0.000167. Considering the nature of the extraction procedure (which involves 0.1N HCl solvent, 120 °C temperature for 62 min), no hydrolysis of fucoidan was performed. The concentration of fucoidan in the crude extract and purified fractions was directly determined using a calibration curve of commercial fucoidan, purchased from Sigma.