Cp 411 ph meter

The acid activity of the molds on the sulfur polymer concrete composites was investigated in a liquid culture, using an Mo2 medium (KH₂PO₄ 1.0 g, (NH₄)SO₄ 0.3 g, MgSO₄ × 7H₂O 5.0 g, glucose 5 g, yeast extract 10.0 g, water 1 L), with the addition of sulfur concrete composites under the following conditions—1 mL of mold inoculum, incubation time 2 months, temperature of 27 ± 2 °C. After 1 and 2 months, the pH of the medium was measured and the samples were tested for the presence of acid metabolites produced by the molds. The pH of the liquid media, with and without the addition of sulfur polymer concrete composites, was measured using an CP-411 pH meter (ELMETRON, Zabrze, Poland). The acid activity was determined using a 10-fold concentration of the medium after the mold culture. The tests were carried out by HPLC–MS (ThermoScientific, Waltham, MA, USA), using a Surveyor liquid chromatograph with ThermoScientific PDA and RI detectors and a mass spectrometer (LTQ Velos, ThermoScientific, Waltham, Massachusetts, USA), in accordance with a previously method described [39 (link)].

The soluble solids content in the juice was determined using a refractometric method [19 ] with ATAGO PAL-3 refractometer (ATAGO, Tokyo, Japan). The pH of juice was determined by the pH-metric method [20 ] with CP-411 pH meter (Elmetron, Zabrze, Poland). Juice density was determined by the pycnometric method at 20°C using distilled water as a model liquid.

The pH was measured 24 h after slaughter using an Elmetron CP-411 pH
meter with a dagger electrode calibrated at pH values of 4.0, 7.0, and 9.0.
The colour of LL and GM samples was measured on the meat surface, after 30 min of blooming, using a Minolta CR-410 (Konica-Minolta) colourimeter. The
following colour coordinates were determined: lightness ( $L^{*}$ ), redness ( $a^{*}$ )
and yellowness ( $b^{*}$ ), colour saturation ( $C^{*}$ ), and hue ( $H^{*}$ ). Measurements were
performed three times for each sample.
The expressed juice was determined by the Grau and Hamm (1953) method.
Samples (0.3 g) of meat were placed on Whatman filter paper no. 1 and held
under a pressure of 2 kg for 5 min. The outline area of the expressible
juice and the meat film was traced, and two areas were measured using a
planimeter. The results have been calculated in units of square centimetres per gram of meat.

A solution was prepared to demineralise the hard tissues of the tooth, the composition of which is shown in Table 1 [25 (link),38 (link)].
The teeth were divided into two groups. Then, 1 L of demineralisation solution was poured into one container in which 6 teeth (the test group) were placed. pH = 6.2 of the solution was then determined using acetic acid and potassium hydroxide, depending on the fluctuation of the pH value [39 ]. The container was placed in an incubator at 37 °C for a period of 5 weeks. The conditions in the incubator mimicked the conditions in the oral cavity to initiate the process of initial caries formation. During the entire 5-week period, the pH was measured daily using a CP 411 pH-meter (Elmetron, Gliwice, Poland), with adjustments of high pH values with acetic acid and low pH values with potassium hydroxide to maintain a constant level of pH = 6. The remaining 6 teeth, which constituted the control group, were kept in distilled water. After 5 weeks, the teeth of both the test and control groups were rinsed three times with distilled water and thoroughly dried.