Hi! You write about wavelength (analytical line), so your ICP measurement technique is ICP-AES (ICP-OES), not ICP-MS.

Which lines to use depends not only on the elemental chemical composition of your samples, but also on the spectral resolution of your spectrometer. Appropriate reference materials with certified REE content are crucial to assess the validity of spectrometric measurements. They should be mandatory, especially in your case. It would probably be necessary to initially determine the elemental composition of your samples in order to select the appropriate elemental reference materials. To some extent, you can help yourself by preparing mixtures with the intended elemental composition yourself, but it is better to rely on certified materials. As for the measurement side of REE itself, there are many studies or addresses available on this subject on the Internet, also on this website. As for specifics about REE measurements using the ICP-AES technique, I myself dealt only with trace amounts, easily measurable with this technique (Sc, Y, La, Yb, Lu). Maybe someone who has dealt with materials containing large amounts of various REEs will respond.

Regards

Z.J.

The answer Zbigniew Jońca provided is informative and helpful. It is true that the ICP measurement technique you are using is ICP-AES, not ICP-MS. The selection of wavelengths to use for each analyte depends on the elemental chemical composition of your samples and the spectral resolution of your spectrometer.

It is important to use appropriate reference materials with certified REE content to assess the validity of spectrometric measurements. These reference materials should be mandatory, especially in your case. It would be necessary to initially determine the elemental composition of your samples to select the appropriate elemental reference materials. While you can prepare mixtures with the intended elemental composition yourself, it is better to rely on certified materials.

There are many studies and resources available on the internet regarding REE measurements using ICP-AES technique. You can find more information on this subject on this website and other online libraries.

Addenda

Certainly! Here are some resources that you may find helpful:

• Agilent Technologies has published an application note on the direct measurement of trace rare earth elements (REEs) in high-purity REE oxide using the Agilent 8800 Triple Quadrupole ICP-MS with MS/MS mode. The application note provides detailed information on the challenges of measuring REEs and how to overcome them using ICP-MS [1].
• A study published in the journal Analytical Chemistry describes an ICP-AES method for the determination of 12 rare earth elements and yttrium in silicate materials. The study details the dissolution and separation procedures used to determine the elemental composition of silicate materials[ 2-3].
• The National Energy Technology Laboratory has published a topical report on the analysis of rare earth elements in geologic samples using inductively coupled plasma mass spectrometry (ICP-MS). The report provides detailed information on the sample preparation, instrument calibration, and data analysis procedures used to measure REEs in geologic samples [4].

https://www.agilent.com/cs/library/applications/5991-0892EN_AppNote_8800_REE.pdf

Article Determinations of the REE and Y in silicate materials with ICP-AES

https://link.springer.com/content/pdf/10.1007/BF00470631.pdf

https://www.netl.doe.gov/sites/default/files/netl-file/Rare-Earth-Trace-Bulk-Elemental-Analysis-ICP-MS-Topical-Report-4-14-2016.pdf

Here are some additional references that you may find helpful:

Article A comparison of INAA and ICP-MS/ICP-AES methods for the anal...

Article Determinations of the REE and Y in silicate materials with ICP-AES

https://link.springer.com/content/pdf/10.1007/BF00470631.pdf

Good luck

Dear, this answer deployed AI for rearranging the response and providing references

E.A. Gawad Zbigniew Jońca Thank you both for sharing your knowledge.

Yeah, I agree there should be a certified reference material but all of those CRMs in the market have been developed for rock samples that only contain mineral phases, but in the case of industrial solid waste which is a mixture of plastics and metals, I thought using those CRMs in the market wouldn't provide an accurate analysis. So my question was how can we deal with such cases to accurately measure metal concentration?

AI answers

Draft1

There are a few ways to select the proper wavelength for concentration of rare earth elements (REE) in ICP data without a certified reference material (CRM).

One way is to use a wavelength table. Wavelength tables list the most sensitive and selective wavelengths for each element. For REEs, the most sensitive wavelengths are typically in the 250-350 nm range. However, it is important to note that the most selective wavelengths may vary depending on the matrix of the sample.

Another way to select the proper wavelength is to use a line spectral profile. A line spectral profile shows the intensity of the emission line at different wavelengths. This can be helpful for identifying interferences from other elements. To use a line spectral profile, simply measure the intensity of the emission line at the wavelength of interest and compare it to the intensity of the emission line at other wavelengths. If the intensity of the emission line at the wavelength of interest is significantly higher than the intensity of the emission line at other wavelengths, then it is likely that the wavelength of interest is free from interferences.

Finally, it is also possible to use a combination of wavelength tables and line spectral profiles to select the proper wavelength. This approach is often the most effective for complex samples, such as industrial solid waste.

Here are some specific tips for selecting the proper wavelength for REE analysis of industrial solid waste:

• Use a wavelength table to identify the most sensitive and selective wavelengths for each REE.
• Measure the line spectral profile for each REE at the wavelength of interest.
• Compare the intensity of the emission line at the wavelength of interest to the intensity of the emission line at other wavelengths.
• Select the wavelength that has the highest intensity emission line and the fewest interferences.
• If possible, run a CRM to verify that the selected wavelength is accurate.

If it is not possible to run a CRM, then it is important to be aware of the potential for interferences. One way to reduce the risk of interferences is to use a matrix-matched standard. A matrix-matched standard is a solution that contains the same elements as the sample, but at known concentrations. By running a matrix-matched standard, it is possible to correct for any interferences that may be present in the sample.

Another way to reduce the risk of interferences is to use a high-resolution ICP spectrometer. High-resolution ICP spectrometers are able to separate emission lines from different elements more effectively than low-resolution ICP spectrometers. This can be helpful for eliminating interferences from other elements.

By following these tips, it is possible to select the proper wavelength for REE analysis of industrial solid waste without a CRM. However,

Draft2

It is difficult to select the proper wavelength for the concentration of REEs in ICP data without a CRM, but there are a few things you can try:

If you are unable to find a suitable CRM, you may want to consider contacting an ICP laboratory for assistance. They may be able to help you to select the proper wavelengths and to develop a calibration curve for your samples.

Here are some specific recommendations for measuring REEs in industrial solid waste using ICP:

• Sample preparation. The sample preparation is very important for this type of analysis. The samples must be completely dissolved and any suspended solids must be removed. You may need to use a strong acid, such as aqua regia, to dissolve the samples.
• Wavelength selection. The following table shows some recommended wavelengths for measuring REEs in ICP:

ElementWavelength (nm)

La 394.909

Ce 422.673

Pr 440.094

Nd 444.798

Sm 369.617

Eu 412.908

Gd 342.247

Tb 379.903

Dy 353.508

Ho 339.892

Er 375.881

Tm 385.629

Yb 398.798

Lu 328.961

• Calibration curve. If you are using a standard addition curve to calibrate your ICP, you should make a standard solution that contains a range of REE concentrations. You can then measure the REE concentrations in your samples and compare them to the standard solution to determine the concentration in your samples.

It is important to note that the above recommendations are general guidelines. The specific wavelength selection and calibration procedures may vary depending on the type of ICP instrument that you are using and the composition of your samples.

Draft2

There is no definitive way to select the proper wavelength for the concentration of REEs in ICP data without a CRM. However, there are a few things you can do to improve your chances of getting an accurate result:

It is important to note that even if you follow all of these steps, there is still a chance that you will not get an accurate result without using a CRM. This is because the matrix of your samples can affect the emission intensities of the REEs in unpredictable ways.

In the case of industrial solid waste, which is a mixture of plastics and metals, it is important to choose a digestion method that will completely dissolve all of the REEs in the sample. This may require using a strong acid, such as hydrofluoric acid. Once the sample has been digested, it is important to filter the solution to remove any undissolved solids.

Here are some additional tips for accurately measuring metal concentrations in industrial solid waste:

• Use a representative sample of the waste.
• Be careful not to contaminate the sample during collection and preparation.
• Use a calibrated instrument and appropriate standards.
• Replicate your measurements to ensure accuracy.

If possible, it is always best to use a CRM to calibrate your instrument and verify the accuracy of your results. However, if a CRM is not available, following the steps above will help you to get the most accurate results possible.

Good luck

Look for descriptions of the analytical procedures used (with ICP-AES measurements) in articles on industrial waste containing rare earths, published in specialized journals such as the Journal of Rare Earths and similar.

Link: https://www.sciencedirect.com/journal/journal-of-rare-earths/issues

Zbigniew Jońca Yeah, I looked through all the papers and found a few papers for this:

Article Improved borate fusion technique for determination of rare e...

Article Characterization of different types of electronic waste: hea...

We had an analogous problem in the analysis of ore leach solutions. Lines recommend for the REEs, U and Th give, in general, unacceptable results. We did not have certificate material compatible with our solutions. Therefore, we used some references books that presented the interference lines for the REEs. Then we prepared the standard with the REEs , U and Th. We used all lines for the REEs, U and Th and performed calibration curves. Then we analyzed the standard solutions of severely elements that could be present in our leach solution. Including the REEs, U and Th.

Based in the literature information and the results of analysis of the standards we are more confident to choose the best lines for each REE , U and Th.

See:

15 Huang B, Wang X, Yang P, Ying H, Gu S, Zhang Z, et al. An atlas of high resolution spectra of rare earth elements for inductively coupled plasma atomic emission spectroscopy. Cambridge: The Royal Society of Chemistry; 2000.

And

http://dx.doi.org/10.4322/2176-1523.20222637

Luiz Rogerio Pinho de Andrade Lima Thank you for sharing your experience.

Dear college,

Please, show the all elements (concomitants) and REEs, which must determinate in the corresponding samples.

I recommend the corresponding steps:

1. The samples must crushed and ground prior to the sieving.

2. Selection of: an appropriate digestion procedure - acid type (HCl, HNO3, aqua regia) ; particle size; waste-to-acid ratio.

3. Estimation of the chemical composition of the samples. This information is needed for Line selection of REEs – in other to select the prominent lines, which are free of line interferences in the presence of corresponding elements.

4. Analytical task in the analysis of waste materials requires the determination of the all presented elements [1]. In this case the inter element interferences must take in account. In some cases the presence of concomitants generally cannot permit the selection of the most prominent lines of REEs. The general purpose is to select these prominent lines, which ensured the lowest possible detection limits by using a given ICP-OES system. There I am listed the most sensitive lines of REEs , which are set in order of the sensitivity in ICP, in accordance of Line Coincidence Table for Inductively Coupled Plasma Atomic Emission Spectrometry [2] ( in nm). The first prominent lines is with highest sensitivity (the most prominent line), follows from second, third, fourth:

La II 333 749 La II 379 478 La II 408 672 La II 412 323 (La 394.909) *

Ce II 413 765 Ce II 413 380 Ce II 418 660 Ce II 399 924 (Ce 422.673) *

Pr II 390 844 Pr II 414 311 Pr II 417 939 Pr II 422 535 (Pr 440.094) *

Nd II 401 225 Nd II 430 358 Nd II 406 109 Nd II 415 608 (Nd 444.798) *

Sm II 359 260 Sm II 442 434 Sm II 360 949 Sm II 363 429 (Sm 369.617)*

Eu II 381.967 Eu II 412 970 Eu II 420.505 Eu II 393.048 (Eu 412.908) *

Gd II 342 247 Gd II 336 223 Gd II 335 047 Gd II 335 862 (Gd 342.247) *

Tb II 350 917 Tb II 384 873 Tb II 367 635 Tb II 387 417(Tb 379.903) *

Dy II 353 170 Dy II 364 540 Dy II 340 780 Dy II 353 602 (Dy 353.508) *

Ho II 345 600 Ho II 339 898 Ho II 389 102 Ho II 347 426 (Ho 339.892) *

Er II 337 271 Er II 349 910 Er II 323 058 Er II 326 478 (Er 375.881) *

Tm II 313 126 Tm II 346 220 Tm II 384 802 Tm II 342 508(Tm 385.629)*

Yb II 328 937 Yb II 369 419 Yb II 289 138 Yb II 222 446 (Yb 398.79) *

Lu II 261 542 Lu II 291 139 Lu II 219 554 Lu II 307 760 (Lu 328.961*

*In accordance with Prof. E.A. Gawad (answer from October 2)

The comparison show that the spectral lines of REEs, which are shown from Prof. E.A. Gawad are not in accordance with Line Coincidence Table [2].

I ask Prof. E.A. E.A. Gawad to show references, were the prominent spectral lines of REEs are recommend.

In addition, the authors of Ref. [1] are used the prominent lines of REEs in accordance with Line Coincidence Table [2].

5. The standard addition curve for calibration is not appropriate for ICP- OES, because of the spectral interferences.

The analytical evaluation function is assumed to be a straight line through the origin. Spectral interferences affect the intercept, if the curve is plotted on a linear scale. Multiplicative interferences affect the slope of a calibration curve [3]

6. Certified reference materials cannot use for line selection. Certified reference materials must use for experimental demonstration of the accuracy of analytical results.

7. Our experience is in the determination of Y, Sc, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb и Lu as impurities in Y2O3, La2O3, CeO2, Nd2O3,Pr6O11, Sm2O3, Eu2O3 , Gd2O3 , Er2O3 , Yb2O3 , Lu2O3, Tb2O3 , Dy2O3 , Ho2O3 , Tm2O3 , as pure rare earth matrices as well as and determination of REEs as dopants in single crystals by using ICP-OES systems with holographic gratings (low level of stray light) and photomultipliers as detectors The results were published in Spectrochimica Acta part B [4 – 11].

References

[1]. Merve Tunali, Mehmet Meric Tunali, Orhan Yenigun, Characterization of different types of electronic waste: heavy metal, precious metal and rare earth element content by comparing different digestıon methods, Journal of Material Cycles and Waste Management (2021) 23:149–157 https://doi.org/10.1007/s10163-020-01108-0

[2]. P.W.J.M. Boumans, Line Coincidence Table for Inductively Coupled Plasma Atomic Emission Spectrometry, Pergamon, Oxford, 1980, 1984.

[3]. P.W.J.M. Boumans, A century of spectral interferences in atomic emission spectroscopy—can we master them with modern apparatus and approaches? Fresenius Z. Anal. Chem. 324 (1986) 397– 425.

[4]. N.Daskalova, S,Velichkov, N.Krasnobaeva, P.Slavova, "Spectral interferences in the determination of traces of scandium, yttrium and rare earth elements in 'pure' rare earth matrices by inductively coupled plasma atomic emission spectrometry –Part I. Cerium, neodymium and lanthanum matrices", Spectrochim. Acta and Spectrochim. Acta Electronica, Part B 47 (1992),E 1595 - E1620.

[5]..S.Velichkov, N.Daskalova, P.Slavova "Spectral interferences in the determination of traces of scandium, yttrium and rare earth elements in 'pure' rare earth matrices by inductively coupled plasma atomic emission spectrometry – Part II. Praseodymium and samarium", Spectrochim. Acta Part B 48 (1993) E 1743-E 1789

[6]. N.Daskalova, S.Velichkov, P.Slavova "Spectral interferences in the determination of traces of scandium, yttrium and rare earth elements in 'pure' rare earth matrices by inductively coupled plasma atomic emission spectrometry –Part III. Europium., Spectrochim. Acta Part B 51 (1996) 733-768

[7]..S. Velichkov, E. Kostadinova and N. Daskalova, Spectral interferences in the determination of traces of scandium, yttrium and rare earth elements in “pure” rare earth matrices by inductively coupled plasma atomic emission spectrometry. Part IV. Lutetium and yttrium, Spectrochim. Acta Part B 53 (1998) 1863 – 1888

[8]. S. Velichkov, L. Aleksieva, E. Kostadinova and N. Daskalova, Spectral interferences in the determination of traces of scandium, yttrium and rare earth elements in “pure” rare earth matrices by inductively coupled plasma atomic emission spectrometry. Part V. Gadolinium and erbium, Spectrochim. Acta Part B 55 (2000) 689-729 - IF = 2.719

[9]. L. Aleksieva, N. Daskalova, S Velichkov, Spectral interferences in the determination of traces of scandium, yttrium and rare earth elements in “pure” rare earth matrices by inductively coupled plasma atomic emission spectrometry. Part VI. Ytterbium ,Spectrochim. Acta Part B 57 (2002) 1339-1350.

[10]. [I. Kolibarska, Serafim Velichkov, Nonka Daskalova, “ Spectral interferencesn the determination of traces of scandium, yttrium and rare earth elements in “pure” rare earth matrices by inductively coupled plasma atomic emission spectrometry. Part VII - Terbium , Dysprosium, Holmium and Thulium, Spectrochim. Acta Part B 63 (2008) 603, doi:10.1016/j.sab.2008.03.007i

[11]. N.Daskalova, S.Velichkov, P.Slavova, E.Ivanova, L.Aleksieva, Application of inductively coupled plasma atomic emission spectrometry (ICP-AES) in analytical control of the preparation of single crystals of potassium titanylphosphate, Spectrochim. Acta, Part B 52 ( 1997) 257 -278 -

With kind regards, N. Daskalova