Accuracy, together with accuracy, are desirable qualities in any laboratory analysis. While accuracy refers to the concordance between a result and the actual content that is intended to be measured, accuracy refers to a set of results that is obtained by applying a procedure that has been repeated several times in exactly the same way.
In that regard, ensuring that the conditions under which the experiment is conducted are nearly identical is critical, if the results are to be reproducible or accurate. If a set of samples needs to be heated or shaken at one step of the laboratory analysis, it is desirable that this be done consistently for the same sample and in different samples. Examples of these laboratory tests include:
- Synthesis reactions of organic and inorganic compounds.
- Sequential extraction studies of heavy metals in soils and sediments.
- Dissolving solid samples by using concentrated acids.
- Homogenization of mixtures.
In all these examples phase changes are produced that are made by thermal effect or agitation, or by the combination of both. When performing serial analyzes, having control is desirable for the experiments to be repeatable, and thus improving the results of the analyzes. Therefore, having a reliable heating plate is important.
Effect of constant heating on the accuracy of the results
The analysis of metals from solid samples such as soils, sediments, plant tissues, food samples, among others, requires that the sample be destroyed and solubilized by attack of strong acids concentrated in hot. Therefore, it is important that the mixture is continuously heated to ensure complete extraction of the metals. If warming is not constant and homogeneous, inaccurate results are likely.
On the other hand, when synthesis reactions are made, temperature control is critical, so in the case of using a heating plate, it must supply the desired amount of heat, since different scenarios can occur, which will negatively affect the product to be obtained:
- Product degradation due to heating at higher temperatures.
- Insufficient heating reaction performance.
- Variability in performance results.
Effect of agitation on the accuracy of results
There are laboratory tests that require constant agitation, for short or long periods of time. For example, to prepare solutions that will be used for different purposes, a stirred solid solution is sometimes put into dissolution before bringing to final volume. Another aid that provides agitation is during titrations, where it is required that the holder sample is homogenized with the added titrant and ensure that the reaction occurs completely. In both cases, the accuracy of the analyzes is increased if stirring is constant and reproducible.
In sequential heavy metal extraction studies, where a solid material, such as a soil or sediment, is brought into contact with an extracting solution, the mixture should be kept stirred for several hours so that most of the metal in the solid passes into the solution and is then measured. If, during that time, the agitation is not constant, the results will be unreproducible.
Kalstein heating plates for improving the reproducibility of laboratory experiments
In any laboratory where experiments and analyzes are carried out, it is important as an indicator of the quality of the results, that they are accurate and precise. In this sense, it is required, at least as regards the use of a heating plate, that it is hot in the selected form and for the duration of the experiment. Kalstein equipment manufacturer heating plates are characterized by:
- They reach temperatures up to 180 degrees and shake speeds between 100-1800 rpm.
- Digital display for temperature and speed display.
- Incorporates an additional thermal insulation board that protects the electronic components of the equipment.
Kalstein offers a variety of these devices, for which prices, purchase, quotation and additional technical details can be found on the websites HERE and HERE