Understanding Measurement Traceability

 

Understanding Measurement Traceability

As per ISO 9000 traceability is described as the capability to confirm the history, whereabouts, or use of an item through recorded identification. In the world of chemical analysis, ensuring the accuracy and reliability of results is paramount. This is where traceability comes in. It's like having a universal ruler for measurements. Traceability establishes a link between a specific analysis and internationally recognized standards. Imagine a chain of comparisons: your lab instrument is calibrated against a reference standard, which itself is linked to a national standard, ultimately traceable to the international prototype (like the kilogram). This unbroken chain ensures that measurements, regardless of location or lab, are all referencing the same ultimate standard. This shared reference point allows Analyst to compare results with confidence, development trust in the integrity of test result.

Following the rules of measurement science, traceability is  important for making sure test results are reliable. Since decisions often rely on measurements of things like physical and chemical properties, special centers for measurement science have popped up around the world. These centers are vital because they make sure measurements are accurate and dependable by giving clear references and standards to follow. This helps everyone trust that the measurements are correct and reliable.

In the world of food testing labs, ensuring accurate measurement results is critical. For example a food testing laboratory is analyzing the sugar content in a sample of fruit juice. To ensure accuracy and reliability, the laboratory follows a systematic process:

Sure, here's an example of how measurement results are followed in a food testing laboratory:

 

Let's say a food testing laboratory is analyzing the sugar content in a sample of fruit juice. To ensure accuracy and reliability, the laboratory follows a systematic process:

1. Sample Collection: A sample of fruit juice is collected from a batch for testing.

 2. Calibration: Before starting the analysis, the laboratory internally calibrates its equipment, such as spectrophotometers or refractometers, HPLC etc, using certified reference standards. This ensures that the instruments are accurate and reliable.

3. Testing Procedure: The laboratory follows a standardized testing procedure or validated test method to measure the sugar content in the fruit juice sample.

4. Quality Control: Throughout the testing process, the laboratory includes quality control samples, known as standards, alongside the samples being analyzed. These standards have known concentrations of sugar, allowing the laboratory to verify the accuracy of its measurements.

5. Traceability: The laboratory ensures traceability of its measurement results by using certified reference materials and following established measurement protocols. This means that the results obtained can be traced back to internationally recognized standards.

6. Reporting: Once the analysis is complete, the laboratory generates a report detailing the measurement results, including the sugar content of the fruit juice sample.

In the context of the example provided, traceability refers to the ability to track and verify the measurement results back to internationally recognized standards and reference materials

1. Calibration Standards: The laboratory calibrates its equipment using certified reference standards. These standards have known properties and are traceable to national or international standards.

2. Certified Reference Materials: Throughout the testing process, the laboratory uses certified reference materials alongside the samples being analyzed. These reference materials have known properties and are traceable to established measurement standards.

 3. Established Protocols: The laboratory follows standardized testing procedures. These protocols ensure consistency and accuracy in measurement results and are traceable to international standards.

By adhering to these practices, the laboratory can demonstrate the traceability of its measurement results, providing confidence in the accuracy and reliability of the data generated. This traceability is crucial for ensuring the quality and safety of food products and for maintaining trust in the laboratory's analytical capabilities.

In simple terms, traceability for chemical measurements can be established in two main ways:

1. By comparing the measurement with reference measurements: This means checking the obtained value against measurements done by certified reference material.

2. By referring the measurement to reference standards: This involves connecting the obtained value to established standards, which are themselves linked to reference measurements.

Traceability should be understood in four main ways:

1. Traceability of analytical results: This means ensuring that the obtained analytical results are reliably linked to specific reference materials through a continuous comparison of uncertainties associated with suitable reference materials. This includes certification and the production history of these materials.

2. Traceability of applied standards: This involves ensuring that the properties of standard values can be linked to reference materials through a continuous comparison of uncertainties associated with suitable reference materials. This requires documentary evidence detailing the production history, including properties like homogeneity, stability, and origin. 

3. Traceability of instruments: This refers to maintaining a detailed and up-to-date history of instruments, including installation, usage hours, sample processing, and other relevant parameters. Special attention is given to maintenance, calibration, and repairs to ensure the accuracy and reliability of instrument measurements.

4. Traceability of analytical methodology (procedures): This entails ensuring that traceable results can be obtained through a validated analytical process. This involves validating all analytical procedures to ensure accuracy and reliability in measurement outcomes.

Starts with the international prototype (e.g., kilogram) maintained by international organizations like the Bureau International des Poids et Mesures (BIPM). This represents the ultimate reference point for the measurement.

National Metrology Institutes (NMIs) in each country maintain highly accurate standards traceable to the international prototype.

Secondary reference standards are calibrated against the NMIs standards and are used for calibrating working standards.

Laboratories use working standards to calibrate their instruments used for daily measurements.

The measured values obtained from the lab instruments are ultimately traceable back to the international prototype through this unbroken chain of comparisons.