Should the E+H PH analyzer be calibrated using a standard solution of 6.86 or 7?
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I read in some sources that the conductivity of a solution with a pH of 7 is low, and 6.86 is generally used. On site, it was indeed seen that engineers had calibrated using 6.86 and 4. But according to the E+H documentation, it says that calibration is done using ph4 and ph7, which is a bit confusing. Is pH 7 the best choice, but since it’s difficult to prepare the solution, can we use 6.86 as a compromise?
pH 7 is the best choice, but since it’s difficult to prepare the solution, pH 6.86 can be used as a compromise. By the way!
Hehe, I actually guessed it right. Thank you
I’m telling you responsibly: do not use a correction factor of 6.86, as it will result in significant errors. A standard solution with pH 7 can be prepared easily by oneself.
Question 1: In the settings of the PH analysis instruments from E+H and Mettler, there is an option to select buffers. For example, with Mettler, b1 refers to Mettler buffers, while b2 refers to NBS buffers. For instance, b1 corresponds to the range of 4.00, 7.00, 9.00, etc.; b2 corresponds to 4.00, 6.86, 9.18, etc； --To determine which group corresponds to which series, one needs to carefully read the instructions or look up relevant information; I’m just giving examples here ； Some even have 3 groups, or a fourth group – Custom – which is also related to a certain type of calibration. When selecting the E+H buffer, be sure to enter a secondary password. Second question: Do not use 6.86 in place of 7.00; this value corresponds roughly to the zero potential of glass electrodes, and it will cause the entire calibration curve to shift, resulting in artificial errors ； So it is essential to choose the right buffer group ； Another method is listed as the third option below: Both E+H and Mettler offer the option to manually enter buffer values–I won’t look up the specific terms since they differ between the two brands. The advantage of this approach is obvious: it’s flexible, as there’s no need to repeat the parameter setup ； Furthermore, some electrodes do not come with a temperature probe, meaning the ATC mode is not available. In such cases, it is possible to refer to the temperature chart on the buffer packaging and enter the most appropriate current pH value for the buffer based on the room temperature. For example, alkaline buffers with a pH of 9.18 are most susceptible to temperature effects; at room temperature, their pH may be 9.25 ； It can improve the accuracy of PH measurement