Internal Standard Method Calculator

Calculate Concentrations Using Internal Standards

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Response Factor Calculator

Calculate the relative response factor using calibration standards.

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Unknown Concentration Calculator

Calculate unknown concentration using internal standard method.

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Calibration Curve Calculator

Generate calibration curve using multiple standards.

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Understanding Internal Standard Method

What is Internal Standard Method?

The internal standard method involves:

  • Adding known amount of reference compound
  • Compensating for sample losses
  • Correcting for matrix effects
  • Improving precision

Selecting Internal Standards

Ideal internal standard should have:

  • Similar chemical properties
  • Similar detector response
  • No interference with analyte
  • Stable response
  • Similar concentration range

Method Requirements

For accurate results:

  • Linear detector response
  • Constant response factor
  • No coelution issues
  • Precise measurements
  • Stable instrument conditions

Common Applications

Used in various techniques:

  • Chromatography (GC, HPLC)
  • Mass Spectrometry
  • Spectroscopy
  • Elemental Analysis

Essential Internal Standard Formulas

Response Factor

RF = (Aa × Cis) / (Ais × Ca)

Where:

Aa = Analyte signal

Cis = IS concentration

Ais = IS signal

Ca = Analyte concentration

Unknown Concentration

Cu = (Au × Cis) / (Ais × RF)

Where:

Cu = Unknown concentration

Au = Unknown signal

Cis = IS concentration

Ais = IS signal

Relative Response

RR = (Aa/Ca) / (Ais/Cis)

Linear range check:

RSD of RF < 2%