How is accuracy defined in analytical chemistry?

Accuracy in analytical chemistry is defined as the agreement between the measured value and the true value. This concept emphasizes the importance of how closely a measurement reflects the actual value of the quantity being measured. High accuracy indicates that the measured value is very close to the true or accepted reference value.

In practical applications, achieving high accuracy often involves calibrating instruments, using standard reference materials, and employing rigorous methodological practices. It's important to remember that a measurement can be precise—meaning that it gives similar results when repeated—but not accurate if those results are consistently far from the true value. Therefore, while precision and reproducibility can help enhance accuracy, they are separate concepts focused on the consistency of the measurements themselves rather than how they compare to the actual target value.