YY 0623-2008Test method of soluble fluoride of dental materials (English PDF)

2.1 Equipment

2.1.1 pH meter (potentiostat)

2.1.2 Fluorine compound electrodes

2.1.3 Electronic balance (0.0001g)

2.2 Reagents

2.2.5 6mol/L sodium hydroxide.

2.2.6 5mol/L hydrochloric acid.

2.2.7 10% sodium carbonate.

2.2.8 Water. Water should be consistent with GB 6682 test in three water specifications.

2.2.1 Sodium fluoride (excellent pure or analytical)

2.2.2 cyclohexanediamine tetraacetic acid, CDTA (AR)

2.2.3 Sodium chloride (AR)

2.2.4 Glacial acetic acid (AR)

2.3 Detection Environment

Detecting environment for 23 °C ± 2 °C.

2.4 Solution preparation

2.4.1 Total ionic strength adjustment buffer (TISABII)

Take 1000mL beaker, add about 600mL of deionized water, 4.0 g of cyclohexane tetraacetic acid (CDTA), 57mL of glacial acetic acid and 58g Chloride, dissolved by magnetic stirring, set the beaker in a cold water bath, was added slowly with stirring 6mol/LNaOH, adjusted to pH 5.0 to 5.5, Into 1000mL volumetric flask, add deionized water to the mark.

Sodium fluoride in the oven at 110 °C drying 4h, set dessicator to cool to room temperature, accurately weighed 0.222g to 1000mL volumetric flask Added deionized water and dilute to volume into polyethylene plastic bottle. This fluorine-containing solution at a concentration of 100µg/mL.

2.4.3 Preparation of calibration solution and draw the calibration curve

Pipette respectively amount of the above solution 0.1mL, 0.5mL, 1mL, 5mL, 10mL, 20mL, 50mL moved 100mL capacity Flask, each flask was added 20mL of total ionic strength adjustment buffer (TISABII), deionized water was added to the mark. The Solution concentrations were obtained fluorine-containing 0.1µg/mL, 0.5µg/mL, 1µg/mL, 5µg/mL, 10µg/mL, 20µg/mL, 50µg/mL (You may also need to be formulated calibration solution, so that the fluorine content of the sample in the concentration of the calibration solution). The above solutions were placed 150mL polyethylene plastic cup on a magnetic stirrer, potentiometric instrument and electrode from the fluorine compound of low concentration to high concentration was followed by measuring the electrical Bit value, each potential value to be read after the numerical stability. Draw fluorine concentration on semi-logarithmic graph paper - the potential value of the curve. X-axis Potential value (unit. mV); Y-axis of the fluorine concentration (unit. µg/mL). And draw regression equation.