Elemental Analysis
Elemental Analysis: Determination of elements using ICP-OES, ICP-MS, and AAS
Fundamentals of Elemental Analysis
Elemental analysis is the core foundation for the analysis of metals, heavy metals, and trace elements in various samples. Modern techniques such as ICP-OES, ICP-MS, and AAS enable the precise determination of elements and provide critical data for research, quality assurance, and regulatory requirements.
Elemental analysis and analytical challenges in various fields
Analytical challenges in elemental analysis vary significantly depending on the field. In chemical manufacturing, the focus is on process monitoring and the quality control of synthesized products, whereas food or environmental samples focus on the monitoring of heavy metals and regulatory limit values.
Determination of elements and heavy metals – objectives, accuracy, and detection limits
In elemental analysis, the determination of elements requires the selection of suitable methods based on the sample matrix, concentration, and detection limit. Highly specialized techniques are employed for the analysis of heavy metals and trace elements. ICP-MS (mass spectrometry-based ICP) enables the reliable determination of even the lowest ultra-trace levels. For the precise quantification of mercury, cold vapor AAS (CV-AAS) is used. These methods ensure the highest degree of accuracy and reliability of the measurement results.
Samples and Sample Preparation
Careful sample preparation is crucial for the accuracy of elemental analysis. Samples are taken according to standardized procedures and undergo specific chemical digestion, taking into account the matrix, analytes, and other parameters. Blank values and control standards ensure the validity of each determination and minimize potential sources of error.
Sampling, digestion, and matrix matching
Sample preparation includes sampling, digestion, and matrix matching. Through standardized procedures such as acid digestion and accompanying controls, contamination is avoided, and samples are optimally prepared for the respective elemental analysis.
Avoiding contamination, blank values, and quality control
The use of blank values, reference materials, and both internal and external control standards ensures reliable results. Quality controls safeguard the precision of elemental determination and the overall reliability of elemental analysis.
ICP-MS (Inductively Coupled Plasma Mass Spectrometry)
ICP-MS combines ICP-based ionization with high-resolution mass spectrometry (MS), enabling the precise determination of elements even at ultra-trace levels.
Principle of mass spectrometry, isotope determination, and interferences
In ICP-MS, atoms from the sample are ionized by a plasma and separated according to their mass-to-charge ratio (m/z), allowing for the precise identification of elements and isotopes. Specialized methods minimize interferences and ensure reliable MS analyses in complex matrices.
Ultra-trace analysis, detection of trace elements and heavy metals
Due to its high sensitivity, ICP-MS is particularly suitable for ultra-sensitive MS measurements. Extremely low concentrations of heavy metals and trace elements are reliably detected. Typical applications include environmental analysis, food screening, and high-precision research in chemistry.
Method Selection and Methodology
The choice of suitable methods in elemental analysis depends on the samples, the elements to be determined, and the target concentrations. ICP-OES, ICP-MS, or AAS each offer specific advantages for the precise determination of metals and trace elements.
Method selection (ICP-OES, ICP-MS, AAS) based on matrix, element, and target value
The decision for a specific method depends on the sample matrix, the concentration of the elements to be measured, and the desired target values. For instance, ICP-OES and ICP-MS are suitable for multi-element analysis or trace elements, while AAS is particularly used for selective single-element analysis in analytics.
Separations, Speciation Analysis, and Interference Management
For complex samples or heavy metal analysis, additional steps such as separations, speciation analysis, or targeted interference management may be necessary. These methods ensure that precise and reliable elemental analysis is possible, even in the presence of challenging matrices.
Quality Assurance in Elemental Analysis Testing
Reference materials, control standards, and validated methods ensure the accuracy and reproducibility of elemental analysis. All results are documented in a traceable manner.
Reference Materials, Recoveries, Internal/External Control Standards
The use of reference materials as well as internal and external control standards is central to quality assurance. Recovery studies verify the reliability of the analyses and ensure that every elemental determination is performed in a reproducible and correct manner.
Measurement Uncertainty, Validation, and Documentation of Analyses
Measurement uncertainties are evaluated, methods are validated, and all results are documented to ensure that department-specific requirements, laboratory certifications, and regulatory standards are met.
Applications of Elemental Analysis
Elemental analysis is applied in numerous fields: from metals and alloys and chemical processes to food and environmental samples.
Metals/Alloys and Materials-Related Analysis
The elemental analysis of metals and alloys is a central component of materials testing, quality control, and research. It provides reliable data on the composition and purity of materials.
Chemistry/Process Monitoring and Product-Related Analyses
In chemical processes, elemental analysis supports the monitoring of production steps, compliance with specifications, and product control.
Food and Environmental Samples: Heavy Metals, Trace Elements, Mercury
In food and environmental samples, heavy metals, trace elements, and mercury are monitored to ensure consumer protection and compliance with statutory limit values.
Results and Reporting
The evaluation and interpretation of the elemental analysis provide specific information regarding limit values, compliance, and quality control. Results are transparently documented in department-specific reports.
Data Evaluation, Limit Value Assessment, and Proof of Conformity
Data evaluation includes the assessment of limit values, traceability of analyses, and the preparation of certificates of conformity. This ensures that every elemental analysis meets the requirements of various departments and provides reliable information.
Department-specific Reports and Customer-specific Requirements
Specific reports and tailored evaluations ensure that results are presented in a way that is understandable, practical, and actionable. This enables clients to make specific decisions based on the elemental analysis.
FAQ on Elemental Analysis
Here we answer frequently asked questions regarding elemental analysis, method selection, sample preparation, and the precise determination of elements in various fields.
What detection limits does elemental analysis achieve with ICP-MS compared to ICP-OES for trace elements and heavy metals?
ICP-MS analysis offers significantly lower detection limits than ICP-OES. It enables the determination of trace elements and heavy metals in ultra-trace concentrations within the ng/L (parts per trillion) range. In contrast, ICP-OES typically detects concentrations in the µg/L (parts per billion) range. Due to this high sensitivity, ICP-MS is preferred in modern elemental analysis, particularly for complex samples from the chemical, food, or metals industries.
How much sample material is required, and which sample preparation (preservation/digestion) is ideal for metal, chemical, and food samples?
The required sample quantity depends on the method used. ICP-MS and AAS can operate with just a few milligrams to grams, whereas ICP-OES typically requires several grams. Prior to analysis, careful sample preparation is crucial. This includes homogenization, cleaning, or preservation tailored to the sample type, as well as chemical digestion. This ensures that metals, heavy metals, trace elements, and mercury are reliably made available for analysis using ICP, OES, MS, or AAS.
When is AAS (Atomic Absorption Spectrometry) more appropriate than ICP-based methods for the determination of individual elements?
AAS (Atomic Absorption Spectrometry) is particularly suitable when only individual elements or specific metals need to be precisely determined. Flame AAS and Graphite Furnace AAS (GFAAS) offer high selectivity, while ICP-OES or ICP-MS are better suited for multi-element analysis or trace element determinations. Consequently, atomic absorption spectrometry is frequently used in food and environmental analysis for targeted heavy metal determinations.
How are contaminations in samples avoided so that the analysis and results remain reliable?
Contamination is avoided through standardized sampling and meticulous sample preparation. Clean chemical digestion procedures, as well as the use of blanks and internal or external control standards, ensure the reliability of the results. This ensures that the determination of metals, heavy metals, trace elements, and mercury in elemental analysis remains reliable and reproducible.
What does cold vapor AAS (CV-AAS) offer for the determination of mercury compared to mass spectrometry (MS)?
Cold vapor AAS (CV-AAS) is specialized for the selective and highly sensitive determination of mercury. It achieves very low detection limits and high precision in food, environmental, and chemical samples. MS-based procedures, such as ICP-MS, are more universally applicable for multiple elements and trace elements, but generally offer less specificity for mercury.
What matrix effects influence the determination of elements in plasma, and how do you correct for interferences?
Matrix effects occur in ICP plasma due to concomitant substances such as salts or organic substances, which influence the atomization or ionization of metals and trace elements. They can distort the accuracy of the determination of metals, heavy metals, and mercury. Interferences are corrected using internal standards, correction factors, or specialized separations and speciation analysis. This ensures that elemental analysis remains precise even for complex samples.
Do you offer elemental analytical screenings as well as targeted elemental analysis depending on the field (materials/metals, chemicals, food)?
Yes, elemental analysis encompasses both broad screenings and targeted determinations of individual elements. It is adapted to specific fields so that metals, alloys, heavy metals, trace elements, and mercury are reliably analyzed in chemical, food, or environmental samples.
How are measurement results evaluated (LOD/LOQ) and documented in reports—including limit values and proofs of conformity?
The evaluation is carried out taking into account the LOD (Limit of Detection) and LOQ (Limit of Quantification). Measurement results are documented in field-specific reports. Limit values and proofs of conformity are clearly listed, enabling laboratory clients to make well-founded decisions based on reliable analysis.
Can specialized analytical questions (e.g., heavy metals, ultra-traces) be solved using a cross-method approach—combining ICP-MS, ICP-OES, and AAS?
Yes, complex questions such as the determination of heavy metals in ultra-trace concentrations are frequently solved through the combined use of ICP-OES, ICP-MS, and AAS. Each method contributes its specific strengths: ICP-OES for multi-element analysis, ICP-MS for ultra-sensitive determinations, and AAS for selective individual determinations. This ensures comprehensive and precise elemental analysis.
What are the typical turnaround times for elemental analytical determinations, and which factors (method, sample preparation) shorten the process?
Turnaround times (TAT) depend on the method, sample volume, and sample preparation. ICP-OES and AAS allow for rapid analysis, while ICP-MS for ultra-sensitive trace element determinations can take slightly longer. Optimized sample preparation, standardization, and automated analysis significantly shorten the process, ensuring that results are provided in a timely manner.
