Internal Standard Calibration
Internal Standard Calibration - Related Videos
09:18
Internal Standards
0 Views •
2023
Source: Laboratory of Dr. B. Jill Venton - University of Virginia The goal of many chemical analyses is a quantitative analysis, where the amount of a substance in a sample is determined. In order to accurately calculate the concentration of an unknown from a sample, careful sample preparation is key. Every time a sample is handled or transferred, some of the sample can be lost. There are strategies however, for minimizing sample loss. There are also strategies for coping with sample loss and...
07:43
Calibration Curves
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2023
Source: Laboratory of Dr. B. Jill Venton - University of Virginia Calibration curves are used to understand the instrumental response to an analyte and predict the concentration in an unknown sample. Generally, a set of standard samples are made at various concentrations with a range than includes the unknown of interest and the instrumental response at each concentration is recorded. For more accuracy and to understand the error, the response at each concentration can be repeated so an error...
01:30
Introduction to International Financial Reporting Standards (IFRS)
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2025
International Financial Reporting Standards (IFRS) are globally accepted accounting principles developed by the International Accounting Standards Board (IASB). IFRS aims to create consistency in financial reporting across countries, promoting comparability, transparency, and accountability in financial statements. This standardized approach simplifies reporting for multinational corporations and supports cross-border investment by reducing the complexity caused by varying national accounting...
10:50
Single-cell Gene Expression Profiling Using FACS and qPCR with Internal Standards
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Cited by 7 •
2017
We describe a method to sort single mammalian cells and to quantify the expression of up to 96 target genes of interest in each cell. This method includes the use of internal qPCR standards to enable the estimation of absolute transcript counts.
08:46
A Standardized Method for Measuring Internal Lung Surface Area via Mouse Pneumonectomy and Prosthesis Implantation
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Cited by 22 •
2017
Internal lung surface area (ISA) is a critical criterion for assessing lung morphology and physiology in lung diseases and injury-induced alveolar regeneration. We describe here a standardized method that can minimize the measurement bias for ISA in both lung pneumonectomy and prosthesis implantation mouse models.
FAQs
The internal standard must respond in a sufficiently comparable way to the analyte so that changes affecting measurement influence both signals in a related manner. This similarity makes the analyte-to-standard response ratio more stable than the analyte signal alone. It is therefore central when sample handling or instrumental response varies between measurements.
Keeping its amount constant establishes a consistent reference for every analyte measurement. Analysts can then compare how strongly the analyte responds relative to that reference, rather than interpreting its raw signal in isolation. Consistent addition helps the calibration curve account for differences introduced during preparation, injection, or signal measurement.
Matrix effects and instrumental drift can change measured responses even when the analyte amount is unchanged. Because the sample contains a chemically similar reference, examining the analyte-to-standard ratio can reduce the influence of those changes on the reported concentration. This is especially relevant when raw signals are not fully stable during analysis.
Relying on the analyte signal alone leaves the result more exposed to changes in sample preparation, injection volume, instrument response, or signal loss. A second response provides a basis for comparison, so the measured ratio carries information about both signals. That paired treatment supports more reliable concentration measurements when those sources of variation are present.
The workflow begins by adding the same known amount of a chemically similar internal standard to calibration solutions and samples. Analysts measure the analyte and standard responses, calculate their ratio for each calibration point, and construct a calibration curve from those ratios. They then use the sample ratio and curve to obtain the analyte concentration.
Successful measurements require matched analyte and standard signals from the same solution or sample, together with calibration solutions prepared under the same internal-standard scheme. The approach can be implemented with gas chromatography, liquid chromatography, and mass spectrometry. The essential data are paired responses and their ratio, not the analyte signal alone.
It provides a common quantitative strategy across these techniques when response intensity may vary because of preparation, injection, matrix effects, instrumental behavior, or signal loss. By expressing the analyte response relative to the internal-standard response, analysts can build calibration relationships and obtain concentration measurements that are less dependent on raw signal magnitude.