U 2900 uv vis spectrophotometer

The AC and TPC in ethanol and ethanol-water extracts of two ground spices were determined by using the spectrophotometric DPPH, ABTS, and F–C methods, respectively, according to previously reported protocols [45 (link)]. The AC results were expressed as mmol Trolox equivalents (TE) per 100 g of sample, while the TPC values were expressed as mg gallic acid (GA) equivalents per 100 g of sample. All the reagents used in these methods were of analytical grade and were purchased from Merck Life Science Sp. z o.o. (Poznań, Poland): 2,2-diphenyl-1-picrylhydrazyl radical (DPPH), 2,2′ azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) diammonium salt (ABTS), Folin–Ciocalteu’s phenol reagent (F–C reagent, 2 N), Trolox (6-hydroxy-2,5,7,8-tetramethylchromane-2-carboxylic acid) (TE, 97%), and gallic acid (3,4,5-trihydroxybenzoic acid) (GA, 98%). The resulting absorbance of each obtained solution was measured in five repetitions using a Hitachi U-2900 UV-VIS spectrophotometer (Tokyo, Japan) in a 1 cm glass cell. The AC and TPC results were calculated based on the standard curves: %DPPH = (782.10 ± 5.74)c_TE + (4.03 ± 0.40), %ABTS = (405.39 ± 3.40)c_TE + (10.38 ± 0.30), and TPC = (0.1034 ± 0.0025)c_GA + (0.0814 ± 0.0147) prepared for the working solutions in the concentration ranges of 0.02 and 0.10 μmol TE/mL, 0.01 and 0.15 μmol TE/mL, and 0.35–10.51 μg GA/mL, respectively.

The phytochemical profiles of the elderflower extracts were analysed by chromatographic methods, using HPLC Dionex UltiMate 3000 system which consisted of a DAD Thermo Scientific detector (Germering, Germany). The antioxidant properties of the extracts were evaluated using a DPPH radical scavenging capacity assay, and the FRAP method. The total phenolic content was determined by the Folin-Ciocalteu method. In all cases, the spectrophotometric analysis was performed using HITACHI U-2900 UV-Vis spectrophotometer (Hitachi, Europe Ltd., Stoke Poges, UK).

U-2900 UV-Vis spectrophotometer (Hitachi High-Tech Science, Japan) was used to measure absorption spectra. Fluorescence spectra were recorded with a fluorescence spectrometer F-7000 (Hitachi High-Tech Science, Japan).

Optical rotations were recorded on a Rudolph Autopol IV-T polarimeter. UV spectra were recorded on a Hitachi U-2900 UV–Vis spectrophotometer. IR spectra were recorded on a ThermoFisher Nicolet iS5 FT-IR spectrometer. NMR spectra were acquired on Varian Mercury Plus 400 instrument and Bruker Avance III HD 600 spectrometer using CD₃OD (δ_H 3.31 and δ_C 49.0). HRESIMS were obtained on an AB SCIEX 5600+ Q-TOF mass spectrometer. MCI gel CHP-20P (75–150 μm, Mitsubishi Chemical Corporation, Tokyo, Japan), ODS gel (50 μm, YMC Co., Ltd., Japan), and Sephadex LH-20 gel (GE Healthcare Bio-Sciences, USA) were used for column chromatography. Precoated silica gel GF254 plates (Qingdao Haiyang Chemical Co., Ltd., China) were used for TLC analysis. Semi-preparative HPLC was performed on a Shimadzu Essentia LC-16 with a UV detector (210 and 254 nm) and a Kromasil C₁₈ column (150 × 10 mm, 5 μm, AkzoNobel, Co., Sweden).

The synthesized Se-MMNPs and CuO-MMNPs were characterized using various spectroscopic techniques. The copper oxide and selenium monometallic nanoparticles (MMNPs) were confirmed by the UV–vis spectrum. Using a UV–vis spectrophotometer (U-2900 UV–vis Spectrophotometer—HITACHI High-Tech Science, Tokyo, Japan; λ = 200–1100 nm) and distilled water as the reference solution, the absorbance of synthesized MMNPs was measured over the wavelength range of 200–800 nm [37 (link)]. According to the previously reported method, dynamic light scattering (DLS; Microtrac Nanotrac Wave II, York, PA, USA) and zeta potential studies were carried out using a Zeta sizer Nano ZS (Malvern, Malvern Hills, UK) [38 (link)]. X-ray diffraction (XRD) of the dried powder sample of monometallic nanoparticles was carried out to analyze the crystallinity and phase purity of the sample using D8 Advance Bruker to calculate broad-angle X-ray diffractograms at 60 kv and 60 mA current. Scanning electron microscopy (SEM, Hitachi S-3000N, Tokyo, Japan) was used to characterize the morphology and size of the purified Se-MMNPs and CuO-MMNPs [39 (link),40 (link)].

The total content of carotenoids (TCC) was determined spectrophotometrically (Hitachi U-2900 UV-Vis spectrophotometer, Hitachi, Tokyo, Japan) according to the PN-EN 12136 method [56 ]. To precipitate carotenoids, 1.5 g of the homogenized sample was treated with Carrez I and II solutions, mixed and then centrifuged. Extraction of carotenoids was carried out three times with 25 mL of acetone; petroleum ether (45 mL) was added to the supernatant and mixed thoroughly. The absorbance of ether extract was measured at 450 nm using petroleum ether as a blank sample. The TCC (mg/100 g of fresh weight) was calculated according to the following equation: TCC = A × V × 10⁶/A^%_{1 cm} × 1000 × m, where: A—absorbance of the ether extract at 450 nm; V—volume of extract (ml); A^%_{1 cm}—extinction coefficient of carotenoids in petroleum ether solution; m—sample weight (g).