Accurately controlling the pH value of the reaction system is beneficial for the accuracy of experimental results in biochemistry and molecular biology experiments. CHES buffer, as a zwitterionic Good's buffer that operates in a higher pH range, is widely used. The configuration and determination of solution pH value require rigorous operation and accurate measurement.

CHES powder

Characteristics of CHES buffer

CHES， The Chinese name is 2-cyclohexylamine ethanesulfonic acid, which belongs to zwitterionic compounds and is suitable for experimental environments with relatively high pH values (up to 10). In water, CHES exhibits acidity, which determines the need for alkaline substances to adjust the pH value when preparing buffer solutions to meet the pH range required for the experiment. At 25 ℃, the PKA value of CHES is about 9.3. PKA value is an important indicator for measuring the buffering capacity of a buffer, which determines the pH range within which the buffer exerts its buffering effect. CHES can resist the influence of external acidity and alkalinity in the pH range near its PKA value, and maintain the stability of the solution pH. Generally speaking, the suitable pH range for CHES buffer is between 8.6-10, which makes it indispensable in many biochemical reactions that require alkaline environments. For example, in certain enzymatic reactions, specific enzymes require alkaline conditions to maintain activity, and CHES buffer can provide such a suitable environment.

Configuration steps of CHES buffer solution

1. Reagent preparation: Prepare the required reagents and instruments, including CHES powder, sodium hydroxide solution (1M), pure water, electronic balance, measuring cylinder, pH meter, volumetric flask, sample bottle, etc.

2. Weigh CHES: According to the experimental requirements, weigh 1.036 g of CHES. Due to the molar mass of CHES being MW=207.3 g/mol, this mass can be used to prepare a specific concentration of buffer solution. During the weighing process, attention should be paid to the proper use of electronic scales to ensure the accuracy of the weighing results. Carefully pour the weighed CHES powder into a clean container and add pure water.

3. Dissolve CHES: Add 40 mL of pure water to the container containing CHES powder. During the process of adding pure water, a glass rod can be used to gently stir and accelerate the dissolution of CHES. At this point, 40 mL of CHES aqueous solution is obtained, which is the initial solution for preparing the buffer solution.

4. Adjust pH value: Use a pH meter to measure the pH value of 40 mL of CHES aqueous solution. As CHES is acidic in water, and the pH range of the buffer solution we need is between 8.6-10, alkaline sodium hydroxide solution needs to be added to adjust the pH value. Slowly add 1 mL of 1 M NaOH solution while stirring to ensure thorough mixing of the solution. After adding sodium hydroxide solution, use a pH meter again to test the pH value of the solution. During the process of adjusting the pH value, pay attention to the correct use of the pH meter.

5. Quantification and storage: Transfer the pH adjusted solution to a 50 mL volumetric flask and dilute to the mark with pure water. When setting the volume, pay attention to aligning your line of sight with the scale line of the volumetric flask. After setting the volume, transfer the solution to a 50 mL sample bottle, cap it tightly, and store it at room temperature. During the storage process, attention should be paid to avoiding contamination and light exposure of the solution.

Key points for measuring the pH value of a solution

1. Calibration of pH meter: Before measuring the pH value of CHES buffer solution using a pH meter, it is necessary to calibrate the pH meter. According to the operating instructions of the pH meter, place the electrodes sequentially into standard buffer solutions of different pH values for calibration. After calibration is completed, the pH meter can accurately measure the pH value of an unknown solution. During the calibration process, it is important to ensure that the temperature of the standard buffer solution matches the actual measured temperature to minimize errors.

2. The influence of temperature measurement: The pH value of a solution is affected by temperature, so when measuring the pH value of CHES buffer solution, the measurement temperature should be recorded. During the experiment, it is important to maintain a constant measurement temperature as much as possible. If the measured temperature is different from the standard temperature, temperature correction may be required for the measurement results.

3. Measurement operation specifications: When measuring pH value, the electrode of the pH meter should be slowly inserted into the solution, ensuring that the electrode is immersed in the solution, but not touching the bottom or side wall of the container. Gently stir the solution to ensure even distribution of ions, then wait for the pH meter reading to stabilize. After the reading stabilizes, record the pH value. After the measurement is completed, the electrode should be promptly removed from the solution, rinsed clean with pure water, and gently dried with filter paper to prepare for the next use.

Product packaging

Hubei Xindesheng, as a manufacturer of biological buffering agents, has established a good reputation in the industry. With a professional R&D team and process, the CHES buffer produced has superior quality, high purity, and strong stability. If you have purchasing intentions, please feel free to click on the website for consultation at any time!