News from LabRulezICPMS Library - Week 44, 2025

Our Library never stops expanding. What are the most recent contributions to LabRulezICPMS Library in the week of 27th October 2025? Check out new documents from the field of spectroscopy/spectrometry and related techniques!

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This week we bring you application notes by LECO, Shimadzu and Thermo Fisher Scientific!

1. LECO: Determination of Total Organic Carbon in Soil, Rock, and Shale by Acid Digestion and Combustion

• Application note
• Full PDF for download

Total organic carbon (TOC) determination in soil, rock, and shale is a common analytical tool used for determining locations of natural hydrocarbon fossil fuel deposits. The organic carbon richness of rock samples (TOC%) is one of the most important parameters used in the evaluation of sediments as a potential source for petroleum or natural gas. TOC content controls the hydrocarbon generation ability of rock and the content of adsorbed natural gas within the rock, as it is the source material responsible for the formation of natural hydrocarbon fossil fuel deposits. 

TOC determination can also be used for the assessment of soil quality in agriculture and as a quality control parameter for raw building materials. TOC content is one of the most important constituents of soil due to its capacity to affect plant growth as both a source of energy and a trigger for nutrient availability through mineralization. The determination of TOC is also an important quality control parameter used during the manufacturing of cement, from the raw material until the final product.

Instrument Model and Configuration 

The LECO C832 is a macro combustion carbon determinator that utilizes a pure oxygen environment in a high-temperature horizontal ceramic combustion furnace designed to handle macro sample masses. A weighed sample is combusted, and the combustion gases are swept from the furnace and through anhydrone tubes for the removal of moisture. The combustion gases are then carried to a non-dispersive infrared (NDIR) cell for the detection of carbon (as CO₂).

Typical Results 

Data was generated utilizing a linear, full regression calibration using fractional masses (~0.1 g to ~0.25 g) of LECO 502-950 LCRM Synthetic Carbon (0.14% C), LECO 502-696 LCRM Synthetic Carbon (1.01% C), LECO 502-905 LCRM Synthetic Carbon (5.00% C) and fractional masses (~0.1 g to ~0.5 g) of LECO 502-902 LCRM Calcium Carbonate (12.03% C). The calibration was verified with LECO 502-696 LCRM Synthetic Carbon (1.01% C).

2. Shimadzu: Determination of Metal Elements in Edible Oils Using ICP-MS

• Application note
• Full PDF for download

User Benefits

• It is possible to accurately analyze metal elements in edible oils. 
• Edible oils can be analyzed using only dilution with organic solvents, which simplifies sample preparation and improves throughput. 
• The use of solvent-resistant peristaltic pump tubing enables the addition of internal standard elements in-line, even during the analysis of organic solvents, thereby eliminating the need for manual addition.

Edible oils are essential in our diet. Analyzing metal elements in edible oils is crucial for ensuring food safety and preserving oil quality. The Codex General Standard for Contaminants and Toxins in Food and Feed1) (hereinafter referred to as CODEX) requires the management of heavy metals (such as arsenic and lead) present in edible oils. Additionally, metal ions such as copper, iron, and manganese in edible oils can act as oxidation catalysts, affecting the deterioration of the oil. 

For the analysis of metal elements in edible oils, methods involving the acid digestion of the oil followed by analysis using ICP Optical Emission Spectrometry (ICP-OES) or ICP Mass Spectrometry (ICP-MS) are known. While digestion with acid can remove the organic matrix, it also carries the risk of volatilizing or contaminating the analytes during the complex sample preparation process, which can lead to errors in the analysis results. Furthermore, the complex sample preparations are timeconsuming and limit throughput. Another method involves diluting edible oils with organic solvents and analyzing them by ICP-OES. However, with this method, it can be challenging to achieve sufficient sensitivity for the analysis of harmful trace elementssuch as As and Pb. 

In this Application News, the ICPMS-2050 (Fig. 1) was used to analyze 25 metal elements by simply diluting edible oils with an organic solvent. Spike recovery tests are also performed to verify the validity of the analytical results.

Removal of Interference and Detection Limit 

To analyze metal elements with high sensitivity in organic solvents, it is necessary to eliminate interferences caused by carbon from the organic solvent. For example, there are carbonderived polyatomic ion interferences such as 12C12C+ on 24Mg, 12C16O+ on 28Si, and 40Ar12C+ on 52Cr. By using collision mode with helium gas or reaction mode with hydrogen gas, these interferences can be eliminated, enabling sensitive analysis. As an example, Fig. 2 shows the calibration curve for Cr under each condition. In the No Gas mode, the influence of 40Ar12C+ results in a high background equivalent concentration (BEC), making it challenging to analyze trace amounts of 52Cr. However, in collision mode and reaction mode, interferences can be eliminated, reducing the BEC and enabling the analysis of trace amounts of 52Cr. 

Additionally, the detection limits (DLs) are shown in Table 4. The detection limits were calculated as the concentration that gives a signal equivalent to three times the standard deviation (σ) of the calibration blank sample (STD0). Detection limits of arsenic and lead in edible oils were sufficient to monitor the CODEX standard values of 100 µg/kg (0.1 mg/kg).

Conclusion 

In this Application News, the analysis of metal elements in edible oils was performed using the ICPMS-2050 with the organic solvent injection system. Good spike recoveries were achieved, confirming that trace metal elements in edible oils can be accurately quantified with a simple sample preparation involving only dilution with organic solvents. Since it is possible to analyze without the complex proceduresrequired for acid decomposition, the risk of volatilization or contamination of the analytes during the sample preparation process is reduced. Additionally, the use of solvent-resistant peristaltic pump tubing enables the in-line addition of internal standard elements, further reducing the time required forsample preparation.

3. Thermo Fisher Scientific: Fast routine analysis of trace and ultra trace elements in zinc alloys by Glow Discharge Mass Spectrometry

• Application note
• Full PDF for download

Zinc is used for different applications like corrosion protection, in fertilizers, pharmaceuticals and in energy storage as alternative for lithium-based batteries. Zinc alloys are used e.g. for die casting and as galvanizing alloys¹ . Corrosion of zinc-aluminum alloys is accelerated by small amounts of impurities, especially lead, cadmium, and tin^2,3. Lead and other impurities such as antimony influence the morphology and orientation of electrolytically deposited zinc4 . To ensure consistently high product quality, the analysis of trace and ultra trace elements in zinc and its alloys is essential. There is an increasing demand to specify better grades of zinc and zinc alloys and therefore, better limits of detection are required. With the Thermo Scientific™ Element GD Plus™ Glow Discharge Mass Spectrometer sub-ppb levels of detection can be achieved, much lower than by Spark-OES and GD-OES. The Element GD Plus GD-MS is being used for quality control in routine production for different applications in industrial manufacturing environments. This document describes the fast direct determination of elements in zinc alloys down to ppb level.

Analytical setup 

The flat zinc alloys samples (Figure 1) are analyzed directly, and no digestion is required. The instrumental conditions for the analysis with the Element GD Plus GD-MS are shown in Table 1. To remove any potential sample surface contamination, fast presputtering in continuous DC mode was applied before the data acquisition. Depending on the sample preparation (e.g. milling or grinding), the resulting degree of surface contamination, and the limits of detection required, lower presputter times can be used, leading to even higher sample throughput. Most elements are analyzed in Medium Mass Resolution (R = 4000). Gallium and Yttrium are analyzed in High Mass Resolution (R = 10000) to ensure an interference-free measurement by resolving the analytes from the ZnH and MgZn interferences.

Results 

The Certified Reference Materials BCR-357, BCR-359 and BCR-360 have been used to calibrate Mg, Fe, Ni, Cu, Cd, In, Sn, Tl and Pb in zinc alloys. The calibration lines are displayed in Figure 2, showing excellent linearity. This calibration was used for the quantification of elements in a zinc alloy sample. For the elements that were not calibrated, the Standard Relative Sensitivity Factors (sRSF) of the Element GD Plus GD-MS were used by the software for quantification. With the sRSFs, the semiquantitative results typically fall within ± 30 % of the true values. Table 2 shows the mass fractions for selected elements as well as the relative standard deviation (RSD) of three replicative consecutive measurements on the same spot. Mass fractions in the single digit ppb range can be quantified with ≤ 10 % RSD. For mass fractions ≥ 0.4 ppm the RSD was ≤ 2 %. For mass fractions ≥ 30 ppm the RSD was 1 %. When the result was below the Limit of Detection (defined as 3 x standard deviation of low concentration measurements), it is stated as < Limit of Detection. With the method used, the typical Limits of Detection are in the low single digit ppb range.

Conclusions 

The Element GD Plus GD-MS is an extremely sensitive tool for determining trace and ultra trace impurities in solid samples. The calibration lines in zinc alloy matrices show excellent linearity. Mass fractions at the ppb and ppm level are quantified precisely and reliably. Single digit ppb mass fractions can be quantified with ≤ 10 % RSD. For mass fractions ≥ 30 ppm the precision was 1 % RSD. Interferences are safely eliminated in either Medium Mass Resolution (R = 4000) or High Mass Resolution (R = 10000). Automatic resolution switching within one second enables the routine use of the optimum mass resolution. Surface contaminations are removed by fast presputtering before the data acquisition. The analysis does not require a digestion and is fast with a sample throughput of approximately five samples per hour.