Overview

In analytical laboratories, maintaining accuracy and consistency across various assays is crucial, and certified reference materials (CRMs) play a key role. This blog focuses on a multi-ion CRM solution containing sodium (Na⁺), calcium (Ca²⁺), magnesium (Mg²⁺), potassium (K⁺), and ammonium (NH₄⁺) ions. Designed with precision in mind, this solution offers certified concentrations, providing a reliable reference standard for various laboratory applications, such as ion chromatography and method validation.

Composition of Solution:

Na⁺, Ca²⁺, Mg²⁺: 100 mg/L each

K⁺: 50 mg/L

NH₄⁺: 10 mg/L
Matrix: 0.01 mol/L Nitric Acid (HNO₃)
Grade: ARISTAR®
Storage Conditions: Ambient Temperature

Certification and Traceability

Produced from high-purity raw materials, this CRM is prepared in a matrix of deionized water with 18 MΩ resistivity and sub-boiling distilled acid, filtered through a 0.2-micron filter to eliminate contaminants. The expanded uncertainty in measurement is reported as the standard uncertainty multiplied by a coverage factor (k = 2), ensuring a coverage probability of approximately 95%, as per EA 4/02 guidelines.

Metrological Traceability:

Traceability is key to ensuring that results are accurate and comparable across different laboratories. The CRM solution’s traceability is maintained through calibration against standards traceable to SI units, certified by organizations like NIST (National Institute of Standards and Technology) or BAM (Bundesanstalt für Materialforschung und -prüfung). This unbroken chain of comparisons ensures reliability in data, as all contributing uncertainties are evaluated in the certification process.

Laboratory Equipment Standards

To uphold consistency and reliability, all equipment used in CRM preparation and certification adheres to rigorous quality standards:

Balances: Analytical balances undergo annual calibration and daily checks using weights traceable to DKD.

Glassware: Only Class A laboratory glassware is used, minimizing any risk of measurement error.

Temperature and Humidity Control: Temperature readings are performed using thermometers certified by ISO 17025 accredited labs, and ambient conditions are monitored with a calibrated hygrometer.

Applications

This multi-ion CRM is highly versatile and suitable for various applications:

Ion Chromatograph Calibration: Ideal for calibrating ion chromatographs, ensuring precise detection and quantification of ions.

Analytical Method Validation: Supports method validation, ensuring that ion measurements are accurate and reliable.

Working Reference Sample Preparation: Assists in creating reference samples for laboratory analysis.

Detection Limit and Linearity Studies: Useful in establishing detection limits and validating linearity in analytical methods.

While the CRM solution is generally ready to use, it can be diluted if lower concentrations are required. For accurate dilution, Class A glassware should be used, and direct pipetting from the container should be avoided to maintain integrity.

Stability, Storage, and Safety

Stability:
This CRM has guaranteed stability within ±0.5% of the certified concentration, provided it is stored as directed. If the bottle is partially used, it is recommended to store it in the refrigerator to reduce transpiration, and the cap should be tightly sealed to avoid contamination or concentration shifts. Stability tests are performed according to MQP 5.14.1, and expiration dates may vary across different batches.

Safety:
The CRM solution should be handled according to standard laboratory safety protocols. As it contains nitric acid, appropriate protective gear, such as gloves and goggles, is recommended. For detailed safety precautions, consult the provided safety data sheet.

Homogeneity and Instructions for Use

Homogeneity:
The solution is prepared following an in-house procedure that guarantees homogeneity, ensuring consistent concentration across the entire volume. Before use, it is recommended to mix the solution thoroughly by inversion.

Usage Instructions:
To maintain accuracy when preparing dilutions, only Class A glassware should be used. Concentrations post-dilution are calculated by multiplying the certified concentration by the volume used and dividing by the final volume in the flask. This CRM is specifically designed for laboratory use only, though it can support a variety of analytical requirements beyond calibration.

Quality Management and Certification Standards

This multi-ion CRM solution is produced under a quality management system compliant with:

ISO 9001 for Quality Management Systems

ISO/IEC 17025 for Testing Competence

ISO 17034 for Reference Material Producers

These certifications, along with advanced manufacturing software, ensure that every batch meets strict quality standards, giving laboratories confidence in the reliability and accuracy of their measurements.

With certified concentrations of Na⁺, Ca²⁺, Mg²⁺, K⁺, and NH₄⁺ ions in a 0.01 mol/L HNO₃ matrix, this CRM offers an indispensable standard for accurate ion measurements. Its high-purity formulation, rigorous certification, and traceability to SI units make it ideal for ion chromatography, method validation, and calibration of laboratory equipment. By adhering to ISO standards and quality protocols, this CRM solution provides laboratories with the accuracy and reliability needed for high-quality results.

Note: This CRM is intended strictly for laboratory use. Proper storage and handling are essential to preserve stability and accuracy.