Tests which determine the concentration of a substance are based on Beer's Law. Simply stated, this says that the higher the concentration of a substance, the darker the color developed in the test, so more light is absorbed by the sample.
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pH tests use an indicator which changes color with changes in the concentration of hydrogen ions, or the acidity of the solution.
Octa-Slide Comparator
The eight color standards in the Octa-Slide are placed in a bar so that they can be compared to the sample individually.
Octet Comparator
The Octet Comparator contains eight color standards with built-in filters which eliminate optical distortion. The color standards are arranged so that the sample can be compared to four standards at once.
There are two accessories which may be used with an Octet Comparator. The Bi-Color Reader (Code 2150) neutralizes sample color and/or turbidity to give more accurate readings. The Axial Reader (Code 2070) uses a mirror to extend the viewpath and intensify faint colors of low concentrations for easy distinction. Both accessories attach directly to the comparator and come with complete instructions for use.
Test Strips
Test strips are either dipped or swirled in test solutions. The resulting color reaction is compared to a color chart provided.
Color Chart Comparator
Color charts are laminated color standards. The reacted sample is held against the panel and compared to the color standards.
Electonic methods generally use a special electode for measureing a specific test factor. An electrode is immersed into a sample and an amplified current or voltage is produced and translated into a digital readout.
Electronic colorimeters measure the amount of light which travels through the reacted sample, and convert the measurement to a reading as ppm, absorbance or %T. In addition to colorimeters, LaMotte manufactures instruments to test pH, TDS/conductivity, dissolved oxygen, and turbidity.
Titrimetric
Titrimetric tests can be used to determine the concentration of a substance in a sample solution. After the sample is treated with an indicator, a standard titrant is added until a color change indicates a completed reaction. LaMotte offers four separate types of titration methods, allowing a choice of precision and convenience.
Direct Reading Titrator
The Direct Reading Titrator is a 1.0 mL microburet calibrated to allow direct reading of the test result. Each Titrator has a specific range, but may be refilled to test higher concentrations.
Dropper Pipet
The drop count test uses a pipet to provide fast, reliable measurements in the field. The number of drops used to obtain a color change is multiplied by a given factor to produce the test result.
Automatic Buret
The self-zeroing automatic buret is calibrated from 0 to 10 mL in 0.1 mL increments. It is available with a squeeze valve (pinchcock), glass stopcock, or stopcock.
Dropper Bottle
The dropper bottle test uses bottle tips which deliver a consistent standard drop size to add titrant to the sample. As with the drop count test, the number of drops used to complete the reaction is multiplied by a given equivalence factor to determine the concentration. Many dropper bottle tests use different sample sizes for different equivalences.
Electonic methods generally use a special electode for measureing a specific test factor. An electrode is immersed into a sample and an amplified current or voltage is produced and translated into a digital readout.
