General
pH value	4,01 bei 25 °C
Deviation	± 0,02
Shelf life after opening	3 Monate

The NIST pH buffer solution pH 4.01 from Chauvin Arnoux serves as reference material for precise calibration and fine adjustment of pH measuring instruments and measurement electrodes. It is specifically developed for applications requiring high measurement accuracy and traceability. The solution is packaged in a 125-ml bottle and is ready for immediate use, without requiring additional preparations such as dilution or mixing.

Reference material with certificate
The buffer solution is designed as a certified reference material and provides traceability to an international system. This ensures high measurement reliability and enables validation of measurement results within quality management systems or calibration-related processes. The included certificate documents the specific characteristics and manufacturing conditions.

pH value and accuracy
The pH value is 4.01 at a temperature of 25 °C, with a maximum deviation of ± 0.02. This narrow tolerance range makes the solution particularly suitable for precise calibrations, especially in laboratory environments, the chemical industry, or food monitoring, where small pH changes can have significant effects.

Usage and storage
The solution is ready to use and requires no additional measures before application. The shelf life is 36 months, provided the bottle remains unopened. After opening, the solution remains usable for 3 months, with usage under clean conditions recommended to avoid contamination.

Compatibility and application areas
The buffer solution is designed for calibration of pH meters, pH measuring devices, and measurement electrodes. It is commonly used in laboratories, process control, or quality testing of liquids. The DIN-NIST standardization ensures international recognition and comparability of measurement results.

Technical basis
The solution is based on a NIST standard, which is recognized worldwide as a reference for pH measurements. Using such a standard enables reproducible and verifiable calibration, which may be relevant for certified measurement processes or compliance with standards such as DIN EN ISO 3696.

Advantages in operation
By combining high accuracy, traceability, and direct usability, the buffer solution reduces effort during calibration. Clear labeling and the included certificate facilitate documentation and traceability within quality control procedures.