Fluorescence specific molds are commonly used in boric acid molds, steel ring molds, and some users also use aluminum cup molds or plastic ring molds, mainly for the pre-treatment and molding of X-ray fluorescence spectrometer samples
Overview of specialized molds for fluorescence analysis
The specialized mold for fluorescence analysis is mainly used in the pre-processing and molding process of X-ray fluorescence spectroscopy (XRF) analysis samples. Its core purpose is to press the powder sample into a uniform, flat, and dense sample to ensure the accuracy and reproducibility of the analysis results.
The common types of molds mainly include the following:
Boric acid mold (border mold)
descriptionThis is a classic and commonly used type of mold. The mold ring is usually made of stainless steel or tool steel, while the base and top rod are made of hard steel. When in use, the powder sample is filled into a steel ring, and a large amount of boric acid (or microcrystalline cellulose, etc.) is filled at the bottom and top as a liner and cover layer, and then pressed into shape.
advantageBoric acid pads can effectively absorb the elastic recovery of the sample, reduce the "rebound" effect, and make the sample stronger and less prone to cracking. At the same time, the boronic acid ring forms a clean background, effectively eliminating the interference of sample edge effects on X-ray measurements.
applicationSuitable for the vast majority of powder samples, especially samples in the fields of geology, minerals, cement, ceramics, etc.
Steel ring mold (integral steel mold/non edge mold)
descriptionThe entire mold (ring, base, top rod) is made of high-strength steel (such as mold steel, hard alloy). Directly press the sample powder under high pressure without using boric acid pads.
advantageQuick sample preparation speed and simple steps. The sample surface is pure and free of boric acid dilution, making it particularly suitable for the detection of light elements such as Na, Mg, Al, Si, as boric acid strongly absorbs and interferes with the measurement of these elements.
shortcomingRequirements for the material, hardness, and smoothness of the moldhighThe sample needs to have a certain degree of adhesion, otherwise it is prone to breakage; Mold wear is significant under high pressure.
Aluminum cup/plastic ring mold (disposable mold)
Avoid cross contaminationFor laboratories with frequent changes in trace analysis or sample types, using disposable molds can prevent residual contamination between samples.
cost controllableFor certain samples, one-time use is more cost-effective than cleaning expensive high-pressure steel rings.
convenienceAfter compression molding, the sample piece is usually directly measured on the machine together with the aluminum cup/plastic ring.
descriptionThe mold ring is made of aluminum cups or plastic rings, usually disposable. Cooperate with the steel base and top rod for compression sampling.
advantage：
applicationWidely used in environmental (such as soil, dust), food, medicine, and various sample analyses that require avoiding cross contamination.
Considerations for choosing a mold:
Sample propertiesThe composition, particle size, adhesion, elasticity, etc. of the sample.
Analysis requirementsThe range of analyzed elements (especially whether light elements need to be analyzed), requirements for detection limits and accuracy.
Cost and EfficiencyThe initial investment cost, service life, sampling speed, and operational complexity of the mold.
avoid pollutionIs it possible for the tested element in the sample to react with the mold material or be contaminated.