Tipic Siguranță Măsuri pentru pH Calibrare
The laborator nevoi mai mult calibrare ori, deoarece experimente sunt adesea realizate, și măsurat soluții sunt diferite. At prezent, the calibration methods are general împărțit în un-punct calibrare, două-puncte calibrare, și trei-puncte calibrare. The more calibration times, the higher the accuracy and the more accurate the acidity meter measurement.
Când calibrare instrument instrument înainte măsurare, a standard tampon soluție închidere la pH valoare de test soluție trebui fi selectat. după instrument este calibrat cu a standard tampon soluție în timpul măsurarea, it should be checked again with another standard buffer solution with a a pH difference of about 3, and the error should not exceed ±0.1. Înainte schimbare standard tampon soluție sau test soluție, electrod de de aciditate metru ar trebui fi complet spălat cu apă, și apoi apa ar trebui fi aspirat sus, sau it poate fi spălat cu modificat standard tampon soluție sau test soluție.
To calibrate the pH sondă, două buffer soluții sunt suficiente. If the sample to be tested is acid, please calibrate the probe with buffer solutions with pH 4 and 7, and if the sample to be tested is alkaline, please use buffer solutions with pH 7 and 10 to calibrate. Buffer solutions are sold as powdered granule and solutions. Granule Granule Have the avantaje of long storage time and economy, but ei sunt doar incomod. The finished solution is easy to use, but it is easy to deteriore after opening the the cover. You can divide the finished solution into small beakers for use.
If you use powdered granule, please make a buffer with 50ml deionized water before calibration. Buffer solutions should be aruncat after use for calibration. Prin urmare, the finished buffer solution should be splited into separate packages for use. Never pour used buffer back into the solution bottle.
To measure the pH value of a weak buffer solution with an acidity meter, first use the potassium hydrogen phthalate standard buffer solution to calibrate the instrument, then measure the test solution, and take the test solution again, until the reading of the pH value does not change within 1 minute. Up to ±0.05; then calibrate the instrument with borax standard buffer solution, and then measure as above; the difference between the readings of the secondary pH value should not exceed 0.1, and take the average value of the secondary readings as its pH value. The water used to prepare the standard buffer solution and dissolve the test product should be freshly boiled cold distilled water, and its pH value should be 5.5-7.0. The standard buffer solution can generally be stored for 2 to 3 months, but if it is found to be turbid, moldy or precipitated, it cannot be used any longer.
