Calibration Standards for ICP Spectroscopy
Inductively coupled plasma (ICP) spectroscopy is an analytical technique designed to detect and measure elements from chemical samples. As such, it has a range of applications and is especially important in the biomedical and pharmaceutical industry.
ICP spectroscopy is based on the ionization of a sample by plasma, typically generated through the ionization of argon gas by radio frequency energy. Commonly employed in inductively coupled plasma mass spectrometry (ICP-MS) and inductively coupled plasma optical emission spectrometry (ICP-OES), these two instruments have a number of advantages over comparable technology used for trace element detection. Notably, they allow multiple elements to be measured simultaneously and possess a large analytical range, which outstrips the single element capabilities and limited analytic range of flame atomic absorption and flame atomic emission.
The vital role played by ICP spectroscopy in many industries requires that the technique remains reliably accurate. Instrument calibration involving calibration standards is essential for ensuring accuracy of measurements.
The Importance of ICP Calibration Standards
The signal measured by ICP-MS and ICP-OES detectors corresponds to the number of ions contacting the detector every second. Conversion of this data into a concentration value necessitates the use of calibration standards, which contain known concentrations of elements, and are used to construct a calibration curve. Together with compound-independent calibration, a technique involving the calibration of one chemical species of an element using another as the calibrant, these methods fall beneath the rubric: “external calibration”.
To correct for changes in instrument operating conditions and sample-specific matrix effects that may enhance or suppress the analyte signal, internal standardization is commonly employed. By adding the same quantity of internal standard to each sample, results can be calculated using the ratio of analyte and internal standard signal. Ideally, the internal standard will have chemical and physical properties closely matched to the analyte, so that it behaves in a similar way under operating conditions.
Even when following the calibrations above, analytical bias can still occur if samples and calibration standards are not matrix-matched. Here, “matrix-match solution” can be added to calibration standards to mimic the matrix within a sample. In the case of ICP-MS, another effective method for correcting matrix effects is “isotopic dilution”, in which an isotopically-enriched isotope (calibration standard) of the analyte is added to the sample. The original composition of the sample can be ascertained by measuring the change in isotope ratio.
Inorganic Ventures Calibration Standards
To ensure the accuracy of the ICP results, it is essential to use suitable and reliable calibration standards. Based on extensive expertise in wet chemistry and analysis, Inorganic Ventures certified reference materials (CRMs) include a comprehensive suite of ICP and ICP-MS standards. Their expansive catalog includes a comprehensive range of single- and multi-element solutions designed exclusively for calibrating spectroscopic instruments based on ICP.
ICP standards include:
- Single Element Standards
- Multi- Element Standards
- Isotopic Standards
- Cyanide Standards
- High Purity Ionization Buffers
- Speciation Standards
- EPA Standards
- Platinum Cobalt Color Standard
- Custom Standards
Using high-purity starting materials and strict quality assurance guidelines, Inorganic Ventures ensures that all our ICP standards are fully-NIST traceable and produced to exacting specifications. Furthermore, Inorganic Ventures provides custom-engineering ICP-OES and ICP-MS standards with precision and absolute customer assurance. Contact a member of the team today if you have any questions.