Uv 1650 pc uv vis spectrophotometer

TBARS formation was measured following the method described by Adriana E Scoccia [3 (link)], malonaldihyde, a secondary metabolite and a marker of lipid peroxidation and oxidative stress, which reacts with Thiobarbituric Acid (TBA) to yield pink colored complex that can be measured spectophotometrically. Briefly, 50 μL plasma was diluted in 10 mL CuSO4 (5.0 mmol/L)solution and incubated at 37°C for 3 hours in ultrasonic waterbath with occasional exposure of ultrasonic wave (SonoSWISS SW6 H, Switzerland) to allow the oxidation process. Then 0.5 mL of 0.78% aqueous solution of thiobarbituric acid and 50 μL of acetic acid was added in 0.5 mL of the plasma-CuSO4 mixture. Control was prepared in the same way except CuSO4. The mixture was heated at 80°C for 40 min in a ultrasonic waterbath and absorbances were taken at 532 nm using a spectrophotometer (SHIMADZU UV 1650 pc, UV–vis. Spectrophotometer, Japan). Percentage of oxidation was calculated as follows-
$\mathrm{Oxidation}\left(\mathrm{\%}\right)=\left(\mathit{Aps}-\mathit{Ac}\right).100/\mathit{Ac}$
Where Aps is the absorbance of plasma sample, Ac is absorbance of control.

The DPPH radical scavenging activity of the seven of chemical constituents isolated from rice plant (straw and leaves) of O. sativa was determined by the method of Gyamfi et al. [19 ]. Initially, 400 µL of sample at different concentrations (0, 200, 400, 600, 800, 1000 µM) was mixed with 1.6 mL of 100 mM Tris-HCl buffer (pH 7.4) and 2 mL of 0.5 mM DPPH (Sigma, St. Louis, MO, USA) dissolved in methanol. The reaction mixture was incubated for 20 min at room temperature. The control contained all reagents without the sample, and 10% methanol was used as the blank. Measurements were performed in triplicate. DPPH radical scavenging activity was determined by measuring absorbance at 517 nm using a spectrophotometer (UV-1650PC UV/VIS spectrophotometer (Shimadzu, Kyoto, Japan). The IC₅₀ value (µM) is the concentration at which scavenging activity is 50%.

The transmittance of coating films was measured using a SHIMADZU UV-1650PC UV-Vis spectrophotometer (Columbia, MD, USA) in the range 200–800 nm. The edges of the coating films were adhered to the sanded side of the cuvette so that the test area of the film was on the unsanded side of the cuvette. Before adhering the coating films on the cuvette, the transmittance of the cuvette was measured to subtract it from the transmittance of the coating films/cuvette.

Reagents and solvents were purchased from commercial suppliers and used without purification unless otherwise specified. All experiments involving air and/or moisture sensitive compounds were carried out under an Ar atmosphere. All reactions were monitored with analytical TLC (Merck Kieselgel 60 F254; Merck, Darmstadt, Germany). Flash column chromatography was carried out using EPCLC-W-Prep 2XY (YAMAZEN, Osaka, Japan). Physical data were measured as follows. NMR spectra were recorded on a JNM-ECS-400 spectrometer (JEOL, Tokyo, Japan) using CDCl₃ or DMSO-d₆ as the solvent with tetramethylsilane as an internal standard. IR spectra were recorded on a FT/IR-4200 spectrophotometer (JASCO, Tokyo, Japan). Optical rotations were recorded on a JASCO P-2200 instrument. FAB mass spectra were measured using a JEOL JIM-700 mass spectrometer. Solid-phase ODN synthesis was performed using an nS-8 II oligonucleotide synthesizer (GeneDesign, Osaka, Japan). MALDI-TOF mass spectra were recorded on an ultrafleXtreme mass spectrometer (Bruker Daltonics, Billerica, MA, USA). ESI mass spectra were recorded on a Xevo G2-XS QTof (Waters, Milford, MA, USA). UV/vis absorption measurements and UV melting experiments were performed using a UV-1650PC UV-vis spectrophotometer equipped with a TMSPC-8 T_m analysis accessory (SHIMADZU, Kyoto, Japan).