Use of Innovative Software for Line Selection in Steel Analysis Using High Resolution ICP-AES

The analysis of complex matrices, containing many elements and possibly line-rich elements, often requires high resolution because of the increased risk of spectral interferences. ICP-AES using a monochromator and photomultiplier tube based detection are the most suitable systems for such analysis because they offer the highest resolution achievable, allowing the analysis of many elements, even in complex matrices, using the primary most sensitive lines for an element.

However, line selection remains a crucial step as it can greatly affect the accuracy of the results. The analyst should conduct this step with great care, even if it is long and time-consuming. To assist the analyst in completing this step, HORIBA Scientific developed CLIP, Collection of Line Intensity Profiles, which will suggest the most appropriate lines for a given analysis, which provide adequate sensitivity and freedom from spectral interferences.

CLIP is a versatile tool that can be used with allof HORIBA Scientific high resolution ICP-AES to greatly shorten the line selection step, saving time for the laboratory and the analyst.

CLIP: LINE SELECTION TOOL
The development of CLIP was possible thanks to the unique and proprietary ICP-dedicated database S3-base. This database, initially built using the CCD based detection HORIBA Scientific model ACTIVA-M ICP-AES, contains more than 50,000 lines identified through real ICP experiments and assigned with the corresponding spectroscopic data (wavelength, ionization state, limit of detection…). This database, already described in the literature , is widely used on ACTIVA-M ICP-AES instruments.

To extend the use of the information contained in the S3- base with high resolution ICP-AES, the detection limits have been updated and a mathematical algorithm has been developed to perform the profile calculation for each line. This algorithm considers the Doppler effect on line broadening based on the plasma temperature and the effect on line width of the focal length, the grating, measurement order and the entrance and exit slits of the spectrometer.

Calculations of theoretical profiles are made according to the expected elements and their concentration range as provided by the analyst. This information may already be known by the analyst or it may be determined by a semiquantitative analysis. Semi-quantitative analysis can be performed on Horiba Scientific high resolution ICP-AES through a full spectrum acquisition thanks to the patented High Dynamic Detection feature.

Once the list of elements and concentration ranges are provided, CLIP starts the calculations and displays the profiles for each analyte. For a given analyte line, the lowest expected concentration is displayed along with the
highest concentration expected for the other elements. The most pessimistic conditions are thus displayed and the analyst can validate or reject analyte lines. As the spectra can be displayed for each slit combination, validation can also be performed for the most appropriate combination.