Linear Fit Equation:
Where:
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The linear fit calibration equation describes the relationship between known concentrations (x values) and measured signals (y values) in analytical chemistry. It's used to convert instrument responses into meaningful concentration values.
The calculator uses the linear equation:
Where:
Explanation: The equation establishes a mathematical relationship between concentration and signal, allowing for quantification of unknown samples.
Details: Calibration curves are essential for quantitative analysis in techniques like spectroscopy, chromatography, and electrochemical analysis. They ensure measurement accuracy and traceability.
Tips: Enter the slope and intercept from your calibration curve, along with the x value (concentration) you want to convert to a y value (signal). All values can be positive or negative.
Q1: How do I obtain the slope and intercept values?
A: These are typically calculated using linear regression on your calibration data, often provided by instrument software.
Q2: What does the R² value mean for my calibration?
A: R² indicates how well the line fits your data points. Values closer to 1.000 indicate better linearity.
Q3: When should I create a new calibration curve?
A: When changing methods, instruments, reagents, or when quality control samples fall outside acceptable ranges.
Q4: How many calibration points should I use?
A: Typically 5-8 points spanning your expected concentration range, with more points for wider ranges.
Q5: What if my data isn't linear?
A: You may need to use weighted regression, polynomial fitting, or transform the data (e.g., log transformation).