Internal Standard Concentration

Quantify analyte concentration from internal-standard area and caller-provided response factor.

Description

Internal-standard backcalculation scales an analyte-to-standard area ratio by a supplied standard quantity and response factor.

Internal-standard backcalculation scales an analyte-to-standard area ratio by a supplied standard quantity and response factor. The quantity basis must match the intended result.^[1]

Quantify analyte concentration from internal-standard area and caller-provided response factor.

When to use Internal Standard Concentration

Use this tool to quantify analyte concentration from internal-standard area and caller-provided response factor.

Prepare the measured profile, formula counts, upstream model outputs or caller-defined reference criteria requested. Keep paired entries aligned and units, sample basis and preprocessing consistent.

How to use Internal Standard Concentration and understand its results

Prepare the measured profile, formula counts, upstream model outputs or caller-defined reference criteria requested. Keep paired entries aligned and units, sample basis and preprocessing consistent.
Enter analytePeakArea, internalStandardPeakArea, internalStandardUmol, responseFactor using the field table and calculation rules, then run the tool.
Read analyteConcentrationUmol, areaRatio. The explanation below defines the units, signs, ordering and any flags or placeholder values.
If the tool reports an input issue, correct the values and run it again. Apply the stated assumptions when interpreting a successfully returned result.

Input field	Meaning	Value type; see rules below	Requirement
analytePeakArea	Analyte peak area	number	Required
internalStandardPeakArea	Internal standard peak area	number	Required
internalStandardUmol	Internal standard umol	number	Required
responseFactor	Response factor	number	Required

Enter nonnegative analyte area and positive standard area, standard µmol quantity and response factor. Return area ratio and the scaled value.

analyte=(analyteArea/standardArea)×standardUmol/responseFactor

Units, indexing, boundary conditions and exceptional cases are defined in the calculation rules above.

Output field	Meaning	Value type
analyteConcentrationUmol	Analyte concentration umol	number
areaRatio	Area ratio	number

json

{
  "input": {
    "analytePeakArea": 100,
    "internalStandardPeakArea": 50,
    "internalStandardUmol": 10,
    "responseFactor": 2
  },
  "output": {
    "analyteConcentrationUmol": 10,
    "areaRatio": 2
  }
}

Limitations and assumptions

The output name says concentration, but a standard supplied as an amount in µmol yields an amount basis. No volume conversion or calibration fit is performed.

Numeric inputs must be finite. Follow the calculation-specific rules for overflow, underflow and exceptional cases. Missing required fields, extra fields, wrong value types and violations of the calculation rules are input errors.

Alternative or Complementary methods

Use Internal Standard Normalization: Normalize analyte peak areas against matched internal-standard injections. For a complementary task, use Calibration Backcalculation: Invert a linear calibration curve to estimate sample concentration.

References

Internal Standard Concentration — tool.io

Similar or alternative tools

Internal Standard Normalization
Normalize analyte peak areas against matched internal-standard injections.
Calibration Backcalculation
Invert a linear calibration curve to estimate sample concentration.