Toledo seven multi ph meter

Raman spectra were obtained from 4000 to 150 cm⁻¹, using a Renishaw microscope (Renishaw in via microscope, Wotton under Edge, UK) with Nd:YAG laser excitation and 2 cm⁻¹ resolution, Fourier transform infrared spectroscopy (FTIR) was performed in a Thermo Nicolet spectrometer (Thermo Scientific, Waltham, MA, USA). X-ray diffraction (XRD) patterns were obtained in a Bruker D8 Advance (Bruker AXS GmBH, Karlsruhe, Germany) spectrometer, using Cu Kα radiation collected in 4–100° 2 theta, with a scanning rate of 0.02°/s. The point of zero charge (pH_pzc) was obtained following the methodology of Yazdani et al. [18 (link)] in a Mettler Toledo, SevenMulti pH meter (Tiel, The Netherlands); the so-called ‘drift method’.

The pH was measured in a controlled environment for 20 h at 37 °C from the fermented milk suspension. The pH change during the milk fermentation was monitored with a Mettler Toledo Seven Multi pH meter every four minutes and resulted in 300 pH values for each fermented milk suspension.

Pristine single-walled carbon nanotubes (SWNTs) were purchased from Carbon Solutions, Inc. (P2). 1-aminoantracene (AA), anhydrous acetonitrile (MeCN), and tetrabutylammonium perchlorate (TBAP) were obtained from Sigma Aldrich. Buffered pH solutions were prepared through Britton-Robinson methods48 from pH = 2 to pH = 12. The pH of the buffered solution was measured using a Mettler Toledo Seven Multi pH meter. The pH meter was calibrated with standard buffered solutions (pH 4, pH 7 and pH 10) obtained from J. T. Baker.