Calibration Curve Calculator
Calculate calibration curves using linear regression for analytical chemistry
Enter known concentrations (mg/L, µM, etc.)
Enter measured responses (absorbance, peak area, etc.)
Enter response to calculate unknown concentration
Understanding Calibration Curves
A calibration curve is a method used in analytical chemistry to determine the concentration of an unknown substance by comparing it to a set of standard samples with known concentrations. Linear regression establishes the relationship between concentration and instrument response.
The Linear Regression Equation
y = mx + b
Linear calibration curve equation
y = Response
Measured signal (absorbance, peak area, fluorescence)
x = Concentration
Known standard concentrations
m = Slope
Sensitivity of the method
b = Y-intercept
Baseline signal at zero concentration
R² = Correlation coefficient
Goodness of fit (1.0 = perfect correlation)
Key Concepts
Linear Range
The concentration range over which the response is proportional to concentration. Operating within this range ensures accuracy.
R² Value Interpretation
- • R² > 0.995: Excellent linearity
- • R² = 0.98-0.995: Good linearity
- • R² < 0.98: Poor linearity, check standards
Applications
- 📊Spectrophotometry: Determining protein, DNA, or chemical concentrations via UV-Vis absorbance
- 🧪HPLC/GC: Quantifying analytes based on peak area or height in chromatography
- 🔬ELISA: Measuring protein concentrations in immunoassays
- 🌡️Clinical Chemistry: Analyzing blood glucose, cholesterol, enzymes in diagnostic labs
- 🏭Quality Control: Verifying product concentrations in pharmaceutical and food industries
- 🌊Environmental Testing: Measuring pollutant levels in water and soil samples
📊Quick Reference
Formula:
y = mx + b
Good R²:
> 0.995
Min Standards:
3-5 points recommended
Applications:
Spectroscopy, HPLC, ELISA
Level:
College Analytical Chemistry
🔗Related Calculators
📐Related Formulas
🎯Where It's Used
- 🏥
Clinical Labs
Diagnostic assays
- 🔬
Research Labs
Protein/DNA quantification
- 💊
Pharmaceutical QC
Drug concentration testing
- 🌊
Environmental
Water quality analysis