Du 640 uv vis spectrophotometer

Manufactured by Beckman Coulter

Sourced in United States

The DU-640 UV/Vis spectrophotometer by Beckman Coulter is a compact and reliable instrument designed for absorbance measurements in the ultraviolet and visible light spectrum. It features a dual-beam optical system and a comprehensive software suite to facilitate accurate analysis of a wide range of samples.

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Lab products found in correlation

Atomic force microscope, by Veeco (1 mentions) Spectra max plus 384 microplate spectrophotometer, by Molecular Devices (1 mentions) Nanodrop 2000 uv vis spectrophotometer, by Thermo Fisher Scientific (1 mentions) Thermomixer comfort, by Eppendorf (1 mentions) Fluorolog 3 spectrofluorometer, by Horiba (1 mentions) Equinox 55 ftir, by Bruker (1 mentions) Tecnai g2 spirit biotwin, by Thermo Fisher Scientific (1 mentions)

Close spelling variants of this product

UV-VIS DU 640 DU 640 spectrophotometer DU 640 UV/Vis spectrophotometer UV spectrophotometer

7 protocols using du 640 uv vis spectrophotometer

Calculating IgG-Dye Conjugate Properties

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The molar absorptivity coefficient of the antibodies at 280 nm (ε_p,280) was set to 190,000 M⁻¹cm⁻¹ for IgG according to the manufacturer. The molar absorptivities for the dyes in water were determined to be 130,000M⁻¹cm⁻¹ for LS822 using Beckman Coulter DU-640 UV-vis spectrophotometer, and 230,000M⁻¹cm⁻¹ for IR650 as reported by the manufacturer. The D/P ratio of the bioconjugates was calculated according to a known eq. 223 (link)27 (link).

Where A₂₈₀ is the absorbance of the IgG-dye conjugate at 280 nm and A_D,680 is the absorbance of the conjugate at 680 nm. The absorbance of the dye at 280 nm was corrected by the factor k = A_D,280/A_D,680.

Zhou H., Tourkakis G., Shi D., Kim D.M., Zhang H., Du T., Eades W.C, & Berezin M.Y. (2017). Cell-free measurements of brightness of fluorescently labeled antibodies. Scientific Reports, 7, 41819.

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Characterization of Functionalized SWNTs

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The spectral, morphological, and electrical characteristics of SWNTs before and after being functionalized by MPs were investigated by atomic force microscopy (AFM), Raman, UV-Vis spectrometry, current-voltage (I-V), and field-effect transistor (FET) measurement. AFM images were obtained using an atomic force microscope (Veeco Innova, Santa Barbara, CA, USA). Raman spectra were measured with a Nicolet Almega XR Dispersive microscope with 532-nm laser excitation. The UV spectrum was acquired by a Beckman DU640 UV/Vis spectrophotometer (Beckman Coulter, Inc. USA). Electrical measurements were made using a semiconductor parameter analyzer (Keithley 2636, USA).
For FET measurements, the Si substrate was covered with gold film, which served as the base, and charged with a linear voltage ranging from −60 V to +20 V. The two gold electrodes etched on the SiO₂ surface acted as the drain and source, to which a constant voltage (0.1 V) was applied. A dielectric layer of 100-nm thick SiO₂ was used to separate the base from the source-drain.

Wang H., Ramnani P., Pham T., Villarreal C.C., Yu X., Liu G, & Mulchandani A. (2020). Asymptomatic Diagnosis of Huanglongbing Disease Using Metalloporphyrin Functionalized Single-Walled Carbon Nanotubes Sensor Arrays. Frontiers in Chemistry, 8, 362.

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Temperature-Dependent Protein Characterization

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Protein samples (300 μL) were prepared by adding protein (from stock to a final concentration of 25 μM unless otherwise noted) to cold sodium phosphate buffer (pH 6.8, 20 mM NaPhosphate, 0.5 mM EDTA) containing 200 mM NaCl and were kept on ice for at least 10 minutes before the assay. We chose 25 μM so that we could capture and compare the phase behaviors of the mutants as clearly as possible. Absorbance at 600 nm as a function of temperature was recorded by a Beckman DU-640 UV/Vis spectrophotometer using a temperature ramp rate of 2°C/min increasing from 20°C to 60°C (or 44°C) and then decreasing back to 20°C. Net absorbance values were recorded after subtracting the absorbance value of a buffer control.

Dao T.P., Martyniak B., Canning A.J., Lei Y., Colicino E.G., Cosgrove M.S., Hehnly H, & Castañeda C.A. (2019). ALS-linked mutations affect UBQLN2 oligomerization and phase separation in a position- and amino acid-dependent manner. Structure (London, England : 1993), 27(6), 937-951.e5.

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Synthesis and Characterization of Man-OVA

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Man-OVA was prepared by coupling p-aminophenyl α-d-mannopyranoside with OVA through water-soluble EDC. OVA (6.8 mg) was added to 1.5-mL water (pH 4.75) containing a 50-, 150-, 300-, and 600-fold molar excess of p-aminophenyl α-d-mannopyranoside, and then a 100-, 300-, 600-, and 1200-fold molar excess of EDC, which was added to OVA dropwise, over a period of 30 min at room temperature. The reaction was allowed to proceed for 6 h, and the mixture was desalted by passage through a PD-10 column equilibrated with 0.01 M ammonium bicarbonate (pH 7.8). The protein fraction was pooled and lyophilized. The molecular weight of Man-OVA was determined using matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass analyses. The absorption spectra of OVA (3.8 μM) and Man-OVA (3.8 μM) were measured using a Beckman Coulter DU640 UV/VIS spectrophotometer (Beckman Coulter Inc., Pasadena, CA, USA), and scanned from 400 to 200 nm.

Tang C.C., Shi Y.J., Chen Y.J, & Chang L.S. (2017). Ovalbumin with Glycated Carboxyl Groups Shows Membrane-Damaging Activity. International Journal of Molecular Sciences, 18(3), 520.

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Spectroscopic Characterization of Biomolecules

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A DU640 UV-Vis Spectrophotometer from Beckman Coulter Inc. (Brea, CA) and a Nanodrop 2000 UV-Vis Spectrophotometer from Thermo Fisher Scientific Inc. (Waltham, MA) were used for DTNB and protein concentration determinations. A Fluorolog 3 spectrofluorometer from Horiba Jobin Yvon (Kyoto, Japan), equipped with a Xenon arc lamp of 450 W, was used to obtain fluorescence data (steady state). All sample incubation treatments were carried on a Thermomixer Comfort from Eppendorf AG (Hamburg, Germany). Structural analyses were performed in a Circular Dichroism J-815 spectrometer from Jasco International Co. Ltd. (Tokyo, Japan). Intrinsic Trp fluorescence lifetime measured by time-correlated single photon counting (TCSPC) was performed using a 288 nm pulsed diode light source, with pulse duration <1.2 ns. Right angle emission was detected at 333 nm with 1 MHz rate using a Fluorolog 3 spectrofluorometer from Horiba Jobin Yvon. Bioassays absorbance was measured using Spectramax Plus384 microplate spectrophotometer from Molecular Devices (Sunnyvale, CA) using Soft Max Pro software.

Pérez Medina Martínez V., Abad-Javier M.E., Romero-Díaz A.J., Villaseñor-Ortega F., Pérez N.O., Flores-Ortiz L.F, & Medina-Rivero E. (2014). Comparability of a Three-Dimensional Structure in Biopharmaceuticals Using Spectroscopic Methods. Journal of Analytical Methods in Chemistry, 2014, 950598.

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Comprehensive Characterization of Au-BSA-DOX-FA Nanocomposites

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The as-prepared Au–BSA–DOX–FA nanocomposites’ morphology and sizes were determined using transmission electron microscopy (TEM; Tecnai G2 spirit Biotwin, [FEI, Hillsboro, Oregon, USA]) and high-resolution transmission electron microscopy at accelerating voltages of 10 and 200 kV, respectively. The hydrodynamic diameter and size distribution of the GNPs were determined by dynamic light scattering (DLS) using a standard laboratory-built light scattering spectrometer (Nicomp 380 ZLS; Particle Sizing Systems, Port Richey, FL, USA). X-ray diffraction measurements were made using a AXD D8 instrument (40 kV, 40 mA; Bruker, Karlsruhe, Germany) with Cu-K alpha radiation (λ =1.5406 Å). A spectrometer (Equinox 55 FTIR, wavelength range: 500–4,000 cm⁻¹; Bruker) was employed to record Fourier transform infrared spectrophotometer measurements. The absorption spectrum of Au–BSA–DOX–FA nanocomposites was detected using a DU-640 UV–vis spectrophotometer (Beckman Coulter, Brea, CA, USA) operated in the range of 200–800 nm at different time intervals to determine the different conjugators in the as-prepared products.

Huang H., Yang D.P., Liu M., Wang X., Zhang Z., Zhou G., Liu W., Cao Y., Zhang W.J, & Wang X. (2017). pH-sensitive Au–BSA–DOX–FA nanocomposites for combined CT imaging and targeted drug delivery. International Journal of Nanomedicine, 12, 2829-2843.

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Thermostability of UBQLN2 Proteins

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Protein samples were prepared by mixing determined amounts of UBQLN2, NaCl, and ubiquitin (when appropriate) stocks and buffer to achieve desired concentrations of each component. Absorbance at 600 nm as a function of temperature was monitored on a Beckman DU-640 UV/Vis spectrophotometer and recorded after 2 min of reaching temperatures every 4°C. Absorbance values were reported after subtracting the optical density of buffer. Data were collected in duplicate (some with n=10), and representative traces are presented.

Dao T.P., Kolaitis R.M., Joo Kim H., O’Donovan K., Martyniak B., Colicino E., Hehnly H., Taylor J.P, & Castañeda C.A. (2018). Ubiquitin modulates liquid-liquid phase separation of UBQLN2 via disruption of multivalent interactions. Molecular cell, 69(6), 965-978.e6.

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