Enter your Standard Deviation (σ), Calibration Slope (S), Multiplier Factor (k), Confidence Level, and Number of Replicates into the Limit of Quantification Calculator to find your LOQ, Limit of Detection (LOD), Relative Standard Deviation, and Signal-to-Noise Ratio in your chosen units.
Limit of Quantification (LOQ)
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Limit of Detection (LOD)
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Relative Standard Deviation
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Signal-to-Noise Ratio
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LOD (Limit of Detection) is the lowest concentration that can be reliably detected but not necessarily quantified, while LOQ (Limit of Quantification) is the lowest concentration that can be quantitatively determined with acceptable accuracy and precision. LOQ is typically 3-4 times higher than LOD.
The standard multiplier factor (k) for LOQ is typically 10, while for LOD it's 3. Some laboratories use k=6 or k=20 depending on their specific requirements and regulatory guidelines.
The standard deviation should be calculated from replicate measurements of blank samples or samples at very low concentrations near the detection limit. Use at least 10 replicates for reliable statistics.
LOQ establishes the lowest concentration at which quantitative results can be reported with confidence. It's crucial for method validation, regulatory compliance, and ensuring data quality in analytical laboratories.
LOQ is affected by instrument noise, baseline variability, sample matrix effects, method sensitivity (calibration curve slope), and the precision of the analytical procedure. Improving any of these factors can lower the LOQ.
LOQ should be recalculated whenever significant changes are made to the analytical method, instrumentation, or sample preparation procedures. Regular verification during routine quality control is also recommended.