Spectrum 65 spectrophotometer

HA, Dopamine and HA-Dop conjugates’ spectra have been analysed with a Perkin Elmer Spectrum 65 spectrophotometer in the range between 600 and 4000 cm⁻¹ with a universal ATR Sampling Accessory in solid phase.

Infrared (IR) spectra were recorded in potassium bromide disks on a Spectrum 65 spectrophotometer (Perkin Elmer, MA, USA). Nuclear magnetic resonance (NMR) spectra were recorded in CDCl₃ unless indicated otherwise with Bruker 300 MHz or 600 MHz spectrometers (Bruker, NASDAQ, USA), using tetramethylsilane (TMS) as an internal standard. GC-MS: 6890-5973N GC-MS (Agilent, Palo Alto, CA, USA), chromatographic column HP-5MS 5% phenyl methyl siloxane 30 m × 250 μm × 0.25 μm, carrier gas: He; flow rate: 1 mL/min; column temperature, temperature programmed: the initial temperature of 60 °C rose to 200 °C at rate of 20 °C/min, and then rose to 240 °C at rate of 5 °C/min (60 °C–20 °C/min-200 °C–5 °C/min-240 °C); injection port temperature: 230 °C; Shunt model sample: shunt ratio 40:1; assist line temperature: 285 °C. Ion source: 230 °C; quadrupole: 150 °C; ionization mode: EI; acquisition methods: scanning; scan quality range: 35–520 mAU. The solvents and reagents were used as received or were dried prior to use as needed.

Electronic balance (ARA520, OHAUS CORP., China) was used to measure the mass of standard and green coffee bean samples. Magnetic stirrer with a hot plate (Model 04803-02, Cole Parmer, 230 V, 50 Hz, and 2 Amp, USA) was utilized to dissolve the standard and the green coffee bean samples. Blending device (Electric motor grinder) (GEEPAS CR., Main land, China) was used for grinding green coffee bean samples. Hitachi spectrofluorimeter (Flouromax-4, spectrofluorimeter, USA) with 1 cm quartz cuvette were used to record the excitation and emission spectrum of the solution. Electronic absorption of the solution was recorded using Perkin Elmer instruments. For the UV/Vis and NIR measurements 1 cm quartz cuvette and a double beam UV–Vis-NIR spectrometer (Perkin Elmer Lambda 950, Llantrisant, CF728YW, UK) with wavelength regions 170–3200 nm were used. For the mid IR measurement a sample holder of zinc selenide crystal and Fourier transform (Perkin Elmer, spectrum 65 spectrophotometer, USA) with wave number range 4000-400 cm⁻¹ were used.

Samples were weighed using electronic balance (ARA520, OHAUS CORP, China). Blending device mortar and pestle was used to ground the dried pumpkin samples. Centrifuge machine (800D, China), double-beam spectrophotometer (Lambda 950-UV-Vis-NIR, Perkin Elmer, UK) interfaced with a computer using 2 nm resolution in a 1 cm path length quartz cell and FTIR spectrometer (Perkin Elmer Spectrum 65 Spectrophotometer, USA) with a sample holder of zinc selenide crystal in the attenuated total reflectance (ATR) mode were used for determination of β-carotene.