Limits of detection, identification and determination: a statistical approach for practitioners

For the estimation of the limits of detection, identification and determination, considerations from analytical practice were applied to the statistics of the calibration line and its prediction interval. The detection limit was the concentration calculated from the maximum height of the prediction interval at zero spiking concentration. The identification limit was twice the detection limit and was the lowest concentration that could safely be detected. The determination limit was the lowest concentration fulfilling three criteria: 1. None of the signals resulting from determination limit concentration should interfere with any signal from detection limit concentration, thus providing an unambiguous separation between the two limits. 2. Recovery should be between 70% and 120%. 3. Lowest and highest predictable signal at determination limit concentration should not deviate more than B 30% from the average. Practical analytical guidance and the necessary mathematical formulae are presented.