Glossary Calibration Calibration is the validation of specific measurement techniques and equipment. The bias is the difference between the mean of the measurements and the reference value. The procedure that establishes and corrects the bias is the calibration. At the simplest level, calibration is a comparison between measurements — one of known magnitude or correctness made or set with one device and another measurement made in as similar a way as possible with a second device. Calibration is often regarded as including the process of adjusting the output or indication on a measurement instrument to agree with the value of the applied standard, within a specified accuracy. CAL Check™ System When used in tandem with a CAL Check™ meter, CAL Check™ equipped electrodes permit users to be informed if they have performed a proper calibration. In the event of a dirty or broken electrode or contaminated buffer solution, the system alerts the user to either check the electrode, replace the buffer solution or both. The system also reminds users when the instrument should be recalibrated. Calibration Curve In analytical chemistry, a calibration curve is a general method for determining the concentration of a substance in an unknown sample by comparing the unknown to a set of standard samples of known concentration. A calibration curve is one approach to the problem of instrument calibration; other approaches may mix the standard into the unknown, giving an internal standard. The calibration curve is a plot of how the instrumental response, the so called analytical signal, changes with the concentration of the analyte (the substance to be measured). The operator prepares a series of standards across a range of concentrations near the expected concentration of analyte in the unknown. The concentrations of the standards must lie within the working range of the technique (instrumentation) they are using. Analyzing each of these standards using the chosen technique will produce a series of measurements. For most analyses, a plot of instrument response vs. Analyte concentration will show a linear relationship. The operator can measure the response of the unknown, and using the calibration curve, they can interpolate to find the concentration of analyte. Candela The candela is the luminous intensity, in a given direction, of a source that emits monochromatic radiation of frequency 540 × 1012 hertz and that has a radiant intensity in that direction of 1/683 watt per steradian. CaT Calcium tartrate CE Mark See page 16.5 Checker® Hanna pocket-sized electronic meter. Checkfridge™ Hanna temperature monitor with magnetic backing and remote thermistor sensor on a 1 meter cable. Checktemp® Hanna Electronic Digital Thermometer with sharp-tip probe CIS Commonwealth of Independent States Cleaning Solution The solution used for cleaning the glass bulb of the electrode/ probe once a day or at least once a week to maintain accuracy and to prevent junction clogging. Clip-Lock™ Interrupting an important cycle of analysis due to a malfunctioning burette is a thing of the past. With the Hanna Clip-Lock™ system you can simply substitute the burette and complete all your tests with the same titrant! The Clip-Lock™ exchangeable burette system prevents cross contamination while reducing loss of time and reagents. Burettes simply slide out for quick exchanges, and detaching the aspiration and dispensing tubes from the titrant bottles is easy. COD Chemical Oxygen Demand is a measure of the oxygen equivalent of the organic matter in the sample that is susceptible to oxidation by a strong oxidizing agent. Colorimeter (see Photometer) Colorimetry Colorimetry is concerned with the determination of the concentration of a substance by measurement of the relative absorption of light with respect to a known concentration of the substance. In visual colorimetry, natural or artificial white light is generally used as a light source, and determinations are usually made with a simple instrument termed a photometer, or color comparator. When the eye is replaced by a photoelectric cell (thus largely eliminating the errors due to the personal characteristics of each observer) the instrument is termed a photoelectric colorimeter, or photometer. 16 Glossary 16.7 www.hannainst.com |
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