Hp 8453 uv visible spectrophotometer

The CdSe_core/ZnS_shell DHLA QDs used for the proteomic analysis of D. rerio proteins were produced by the Research Institute for Applied Acoustics (Dubna, Moscow, Russia, http://nanotech-dubna.ru). The QDs were used as a water suspension and analyzed at room temperature. Dynamic light scattering measurements were made with a Nicomp™ 380 ZLC zeta potential and particle size analyzer (Particle Sizing Systems, USA). The absorption spectra were measured with an Agilent/HP 8453 UV–visible spectrophotometer. Fluorescence intensity studies (λ_ex = 312 nm) were performed with a Perkin-Elmer LS-55 fluorescence spectrometer (Maryland, USA). The comparison mixture (MCS-QDs) contained cadmium stearate (45 μM Cd²⁺), zinc acetate (8.1 μM), elemental sulfur (8.1 μM), trioctylphosphine (40.5 μM), and selenium (38.7 μM).

All individual spectra and pseudo-first order kinetics were performed using a thermostatted (23/37°C ± 0.2) Cary 50, Cary 100, or HP8453 UV-Visible spectrophotometer (Agilent Technologies) for reactions ferric heme reactions with nitric oxide (NO) without glutathione in PBS and MeOH/PBS buffer (1 part PBS in 5 parts methanol) unless otherwise noted. For pseudo-first order reactions with fast observed rates such as the ferric heme reaction with NO and reduced glutathione, a thermostatted SX-20 stopped-flow instrumented fitted with a direct mount photodiode array (Applied Photophysics, Ltd.) in an anaerobic chamber was used. Samples were prepared either in a glove box under nitrogen atmosphere or using a Schlenk line under argon atmosphere with oxygen-free buffers and solvents.

The IR spectra were obtained with a FT-IR Spectrum 2000 (16 scans) spectrophotometer (Perkin Elmer, Waltham, MA, USA). ¹H-NMR (Nuclear magnetic resonance) spectra were obtained using an Avance 500 (Bruker, Karlsruhe, Germany) at 500 MHz for solutions in DMSO-d₆. Elemental analyses were carried out on a CHNS-932 (LECO Corporation, St. Joseph, MI, USA) for C, H, N, and S. The melting point was measured using an M-560 melting point instrument (Buchi, Flawil, Switzerland). The absorption spectra were measured in 1 cm quartz cells on an HP8453 UV-visible spectrophotometer (Agilent, Santa Clara, CA, USA). The reflectance and color properties (CIE L*, a*, b*, C*, and h_ab) of the dyed samples were measured using an X-Rite 8000 Series (X-Rite, Inc., Grand Rapids, MI, USA) in specific color measurement conditions (standard light D65, 10° standard observer, and specular component included).