Diluters are used to simplify the process of sample preparation by diluting samples to standard concentrations. Most diluters come pre-programmed with standard (common) dilutions. Common dilutions for concentrated samples are 1/4, 1/10, 1/25, 1/50, 1/100, 1/250, 1/500, 1/1,000, and greater. By using diluters, samples can be prepared in less time than standard manual methods, such as mixing solutions in a volumetric flask. Diluters may also be used to make smaller quantities of a solution, when compared with other analytical techniques, such as atomic absorption spectrometry (AA), gas chromatography (GC), and high performance liquid chromatography (HPLC); thereby limiting solvent consumption and reducing overall waste and disposal costs.
When selecting between diluters, it is important to take the following specifications into account:
- solvent volume
- sample volume
Accuracy describes the nearness of a measurement to the standard or true value, i.e., a highly accurate measuring device will provide measurements very close to the standard, true, or known values. Precision is the degree to which several measurements provide answers very close to each other. It is an indicator of the scatter in the data. The lower the scatter, the higher the precision. Solvent volume is the amount of solvent (the substance that is used to dilute the sample) that the diluter can accept. Generally, solvent volume needs increase as concentration of the sample decreases. Similarly, sample volume is the amount of sample material that diluters are designed to accept.
Once the diluters’ performance specifications are determined, the next step is to determine the display or interface options that best suit the given application. Diluters are available with local interfaces or computer interfaces. Local interface diluters should be selected if the device will be used for single batches, occasional operation, or if the sample preparation requires close supervision and alteration. Local interface options include analog and digital panels for reaction information display and input. Computer interfaces are appropriate for continuous batching of sample, preparations that require numerous steps, or long reaction times, or in laboratory settings where multiple activities are taking place. Additionally, computer interfaces are useful if careful data tracking and logging is necessary, as well as remote display of data.