# FAQ: How Do You Use A Calibration Curve?

The equation will be of the general form y = mx + b, where m is the slope and b is the y-intercept, such as y = 1.05x + 0.2. Use the equation of the calibration curve to adjust measurements **taken on samples with unknown values**. Substitute the measured value as x into the equation and solve for y (the “true” value).

## What does the calibration curve tell us?

In analytical chemistry, a calibration curve, also known as a standard curve, is a general method for determining the concentration of a substance in an unknown sample by comparing the unknown to a set of standard samples of known concentration.

## How does a calibration graph work?

The calibration curve is a plot of how the instrumental response, the so-called analytical signal, changes with the concentration of the analyte (the substance to be measured). The operator prepares a series of standards across a range of concentrations near the expected concentration of analyte in the unknown.

## What is the purpose of creating the calibration curve in this experiment?

The purpose of creating the calibration curve is to correct future measurements made with the same instrument to the correct units of measurement.

## Can a calibration curve be a straight line?

It is indeed possible to make calibration curves. If the straight line passes through the origin, a single calibration point is sufficient. If there is a significant intercept, it may be possible to estimate it with a blank measurement or apply a correction.

## What is a calibration curve absorbance vs concentration?

The difference between calibration curve absorbance and concentration is that the calibration curve is a graph of absorbance and concentration and absorbance is the amount of light absorbed by a sample whereas concentration is the amount of a substance distributed in a unit volume.

## Is a calibration curve linear?

Calibration curve in bioanalytical method is a linear relationship between concentration (independent variable) and response (dependent variable) using a least squares method. This relationship is built to predict the unknown concentrations of the analyte in a complicated matrix.

## How do you do a calibration curve on Excel?

Generating calibration curve in MS Excel

- Generating calibration curve in MS Excel.
- 4) Calculate unknown.
- 1) Graphical display.
- Use chart wizard to generate calibration curve, select “(XY) scatter”
- Select data (left click) and right click to get menu and select add trendline.
- 2”

## How do you know if your calibration curve is acceptable?

The r or r^{2} values that accompany our calibration curve are measurements of how closely our curve matches the data we have generated. The closer the values are to 1.00, the more accurately our curve represents our detector response. Generally, r values ≥0.995 and r^{2} values ≥ 0.990 are considered ‘good’.

## What is meant by calibration?

Calibration is a comparison between a known measurement (the standard) and the measurement using your instrument. Typically, the accuracy of the standard should be ten times the accuracy of the measuring device being tested. In practice, calibration also includes repair of the device if it is out of calibration.

## How do you create a calibration curve in HPLC?

Prepare the calibration curve (graph), that plot of peak area vs concentration using Excel/ relevant software. Draw a best fit straight line on your graph. Make sure the coefficient of determination/correlation is close to one.