Test for contaminationProcess automation including pulverising, dosing and pelletising require an efficient cleaning of all components. HERZOG equipment offers different cleaning options including pressed air, wet cleaning, sand cleaning, and blind samples. We use XRF analysis to minimise potential contamination of sample material. This allows an optimal tuning of cleaning parameters according to the specific requirements of each customer.
Test for homogeneityA representative surface of the sample is essential for obtaining reliable analysis results. Pelletising of material into rings may lead to material decomposition or particle clustering potentially interfering with correct analysis. HERZOG equipment uses various XRF methods for avoiding heterogeneity within the pellets.
Influence of parametersThe results of sample preparation are influenced by various effects like, e.g., particle size effects, matrix effects, particle orientation effects, surface roughness, or fusion bead shape. During the sample preparation process the following parameters are of particular interest:
- Grinding time and grinding vessel
- Grinding aids
- Pressure level and time
- Timing of fusion
- Crucible handling during fusion
- Type of flux and sample for the fusion process
Implication for laboratory automationLaboratory automation should obtain the optimum balance between high sample throughput and best analysis quality. During the process of automation planning we do not only rely on our outstanding expertise but also on tools such as simulation software. Before delivery, the performance of all automation components is extensively tested by using test procedures like XRF analysis and grain size analysis. All parameters are perfectly adjusted and coordinated to obtain best possible analysis results, based on a close cooperation with our customers.
|Some Spectroscopic Analytical Techniques||Sample Excitation Source||Materials Analysed||Typical Sample Preparation||Usual Form of Prepared Sample||Typical Industry||Advantages||Disadvantages|
|Spark or arc optical emission (OES)||Hi-voltage electric spark or arc||Electrically conductive solids||Remelting, milling, or grinding||Flat ground surface||Metals production, education, and environmental||Speed of analysis, and low running costs||Sample has to be conductive, and requires homogeneous sample surface|
|Inductively coupled plasma OES (simultaneous & sequential detection)||R.F. induced plasma||Metallic & non-metallic solids, liquids & powders||Crushing, drilling, milling, or dissolution e.g. acid, alkali or solvent||Solution, solid or aerosols||Metallic and non-metallic, education, and environmental||Sample type and quality versatility||Lengthy sample prep time, and sequential analysis: slower & increased running costs|
|Wave length dispersive X-ray fluorescence (simultaneous & sequential detection)||Primary X-rays||Metallic & non-metallic solids, liquids & powders||Crushing, remelting, milling, grinding, pressing, fusion, or dissolution e.g. acid or solvent||Solution, solid, pressed powder or fused bead||Metallic and non-metallic, education, and environmental||Speed of analysis, and sample type and quality versatility||Sequential analysis: slower & increased running costs|
|Energy dispersive X-ray fluorescence||Primary X-rays||Metallic & non-metallic solids, liquids & powders||Crushing, remelting, milling, grinding, pressing, fusion, or dissolution e.g. acid or solvent||Solution, solid, pressed powder or fused bead||Metallic and non-metallic, education, and environmental||Portable, relatively cheap, speed of analysis, and sample type and quality versatility||Sequential analysis: slower & increased running costs, and lower precision than wave length dispersive.|
|X-ray diffraction||Primary X-rays||Metallic & non-metallic solids, liquids & powders||Crushing. Very little prep, since sample material is used to identify it and it’s crystalline structure||Powders or films||Metallic and non-metallic, education, and environmental||Sample type and quality versatility||N/A since there is no other comparable technique|