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Glossary

Ag/AgCl – Silver/silver chloride reference electrode is good for general purpose applications with a wide temperature range of -5 to 110 °C.

ATC or Automatic Temperature Compensation automatically corrects the measured value based on the temperature of the solution (with use of temperature sensor).

Auto-Buffer Recognition identifies and ensures correct pH buffer values are being used during calibration.

Auto-CAL or Automatic Calibration frees users from cumbersome fine adjustment or manual selection of desired standards/buffer values in calibration routine.

Auto-Data Logging allows measured or stored data sets being transferred seamlessly into memory or external peripherals at preset time interval or whenever readings stabilise.

Auto-Ranging Capability scans and switches to the appropriate measurement range.

Backlit Display offers well-contrasted backlighting on the display for optimum viewing.

Barometric Pressure Compensation compensates oxygen solubility for changes in Barometric Pressure.

Bi-Directional RS232C Linkup provides two-way RS232C communication between meter and computer via a cable to remotely control and manage meter operation.

BNC is known as British Naval Connector or Bayonet Nut Connector. This connector is used to join segments of coaxial cable.

BOD or Biochemical Oxygen Demand is a measure of the amount of oxygen that is consumed by bacteria as they decompose the organic components of waste. DO measurements are usually made at the beginning and end of a five-day incubation period for a standard test.

CAL-Due Prompt reminds user to calibrate the meter at set regular intervals.

CE-Certification or CE Marking is a conformity marking consisting of the letters “CE”. CE is an abbreviation for ‘Conformite Europeenne’, French for ‘European Conformity’. The CE Marking indicates that the product it is affixed to conforms to all relevant essential requirements and other applicable provisions that have been imposed upon it by means of European directives, and that the product has been subject to the appropriate conformity assessment procedure(s). For more information, please refer to website at www.cemarking.net

Cell Constant or k is the ratio of the distance between the two metal plates and surface area of the two metal plates during measurement.

21 CFR Part 11 – A set of criteria set forth by the FDA which qualifies electronic records and signatures to be equivalent in reliability to paper records and handwritten signatures on paper. For more information, please refer to the “Code of Federal Regulations” at www.fda.gov.

Chlorine or Cl is commonly used to disinfect water in pools and wastewater industry. Chlorine may be present in 2 forms – Free and Total Chlorine. Free Chlorine combines with contaminants to form Total Chlorine. The common method of measurement used by the colorimeter is based on the USEPA-approved DPD method of chlorine measurement.

Chlorine Dioxide – The use of chlorine dioxide as a disinfectant is seeing growth in many industrial applications. Unlike chlorine, chlorine dioxide remains a true gas dissolved in solution. The lack of any significant reaction of chlorine dioxide with water is partly responsible for its retaining its disinfecting effectiveness over a wide pH range. This property makes it a logical choice for cooling systems operated in the alkaline pH range, or cooling systems with poor pH control.

COD – The COD Test is often used to measure the amount of organic compounds in surface water by measuring the amount of oxygen required to oxidize and break down an organic compound into carbon dioxide, ammonia and water. The basis of the COD test is that anything can be oxidized into carbon dioxide using a strong oxidizing agent in acidic environments. A blank sample, created by adding all reagents to distilled water is usually used as a control in COD measurements.

Colorimetry – Different chemical substances absorb different visual light frequencies. Since the absorbance of a substance is proportional to its concentration (ie. a more concentrated solution gives a higher absorbance reading), the concentration of a known solute can be measured using a colorimeter.

Conductivity is the parameter representing the capacity of ions in an aqueous solution to carry electrical current.

Cyanuric Acid – In applications where chlorine is used for disinfection, cyanuric acid is often present as a chlorine stabiliser. Low levels of cyanuric acid are beneficial as they prevent wastage of free chlorine by the sun’s UV rays. High levels of cyanuric acid cause the chlorine to take a longer time to kill the micro-organisms. It is important to determine how much cyanuric acid should be added to maximise chlorine efficiency.

DAS or Data Acquisition Software connects the bench meter using a RS232C communications cable and can be used to control the meter from a PC. This software is available with the benchtop series 1100/2100, 1500 and 6000. The software also provides Data Acquisition functions and allows data from the meter to be captured and stored for processing on a PC. Other features of the software are the ability to zoom in to certain areas of the graph, set the length of time to capture data, set meter settings like temperature units, pH and mV alarm limits, calibration reminders, resolution and many other parameters.Updated versions are available on the website www.eutechinst.com

DIN or Deutsches Insitut fur Normung eV is a German national organization for standardization. A DIN buffer set usually refers to the 1.09, 3.06, 4.65, 6.79, 9.23, and 12.75 pH. Selected Eutech meters such as the CyberScan pH 310 is capable of up to 6 points of calibration if the DIN buffer standard is chosen. A DIN connector is a connector that conforms to one of the many standards defined by DIN. Eutech meters that feature the DIN connector include the CyberScan bench series 1500 and 6000.

DPD Method is US EPA accepted for reporting drinking water analyses (Free and Total Chlorine)
and wastewater analyses (Total Chlorine only). Please refer to the “Standard methods for the Examination of Water and Wastewater” and US EPA method 330.5 for wastewater and Standard Method 4500-Cl G for drinking water for more information.

DO or Dissolved Oxygen is the measure of the amount of gaseous Oxygen (O2) dissolved in a solution.

Double-Junction Protection in electrodes is necessary to prevent electrode poisoning. Reference junction poisoning is inevitable especially in cases where there is sulphide content in the sample. Sulphide is known to attack silver in the reference and shorten the electrode’s useful life. With the double junction protection, the ‘poison’ takes longer to reach the reference junction hence extending the electrode’s useful life. The new range of large display waterproof pocket testers feature double junction electrodes for long lasting performance.

Electrode Diagnosis provides useful information on electrode condition and characteristics after
each calibration.

EMC or Electromagnetic Compliance is one of the CE Directives specified for electrical products.
All Eutech products with CE-certification adhere to the EMC Directive. For more information, please refer to www.cemarking.net

EPA or Environmental Protection Agency leads the environmental science, research, education and assessment efforts in the US. For more information, please visit www.epa.gov

Formazin Standards – Formazin was first established by the US Environmental Protection Agency (See EPA) as a Turbidity standard in 1926. However, its importance as a standard has been relegated due to its many shortcomings, one of which being that one of the chemicals which formazin is derived from, hydrazine sulphate, is carcinogenic. Eutech’s Turbidity meters use a safe, non-toxic, non-carcinogenic alternative to formazin standards which can be used for calibration directly without mixing or dilution.

Galvanic Cell consists of two metals, the positive anode and the negative cathode, connected by a salt bridge between the individual half-cells. As the metal electrodes leave electrons behind as they dissolve in the electrolyte. The different properties of the two metals causes them to dissolve at different rates, hence a pressure is created when the number of electrons in either side of the cell differs. The pressure is translated into an electric current proportion to the oxygen concentration in the electrolyte if an electrical circuit is created between the two electrodes. The galvanic electrode does not need polarising time and is able to assume operation immediately.

GLP or Good Laboratory Practices refers to regulations that are observed to ensure high quality experimental standards and reliable data.

HVAC stands for Heating, Ventilation and Air Conditioning System.

HCl is the chemical formulation of Hydrogen Chloride that is a highly corrosive and toxic colorless gas that forms white fumes on contact with humidity. These fumes consist of hydrochloric acid which forms when hydrogen chloride dissolves in water. Hydrogen chloride gases as well as hydrochloric acid are important chemicals in chemistry, science, technology, and industry. A 0.1 M HCl can be prepared as 1 % pepsin solution to break down any protein deposits on an electrode.

IP stands for ‘Ingress Protection’. An IP number is used to specify the environmental protection of enclosures around electronic equipment. These ratings are determined by specific tests. The IP number is composed of two numbers, the first referring to the protection against solid objects and the second against liquids. The higher the number, the better the protection. Eutech products such as the CyberScan waterproof series and waterproof testers have IP67 housing. The first digit ‘6’ indicates total protection against dust and second digit ‘7’ protects against the effects of immersion between 15 cm and 1 m.

IrDA Communications – IrDA stands for Infrared Data Association, a group of manufacturers who developed a standard for transferring data via infrared light waves; a secure wireless link that
allows the meter to be connected to a computer or printer without the help of cables.

ISO 7027 is the water quality standard measured in terms of Turbidity determined by the International Organisation for Standardisation. For more information on ISO, please refer to the website www.iso.org Eutech Turbidimeters TN 100 and TB 1000 (infrared light source models) comply with the ISO 7027 standards.

kPA or Kilopascal refers to a unit of pressure. 1 kPa is approximately the pressure exerted by a 10-g mass resting on a 1-cm2 area. 101.3 kPa = 1 atm. There are 1000 pascals in 1 kilopascal.

KCl refers to the Chemical Compound Potassium Chloride which is a metal halide composed of potassium and chlorine. KCl is used in medicine, scientific applications and food processing. A heated diluted KCl can be used to unclog a reference junction.

LSD or Least Significant Digit refers to the right-most active digit of a digital display.

MTC or Manual Temperature Compensation is an alternative method for temperature compensation through the manual input of sample temperature value. ATC is more practical in most applications.

Multiple-Point Calibration ensures the highest accuracy across the full measurement range.

NIST or National Institute of Standards and Technology is a non-regulatory agency of the
United States Department of Commerce’s Technology Administration. The institute’s mission is to develop and promote measurement, standards,and technology to enhance productivity, facilitate trade, and improve the quality of life. The NIST buffer standards usually refer to pH 1.68, 4.01, 6.86, 9.18, and 12.45. For more information, please visit www.nist.gov

NTU or Nephelometric Units is the preferred expression of Turbidity.

Non-Volatile Memory retains stored data and calibration information indefinitely even if power is disconnected.

Normalisation Temperature is used to standardise measurements to a known ambient temperature value (generally at 20 °C or 25 °C).

Open Pore pH Electrode makes use of a single pore capillary reference junction that is about 200* times larger than a typical ceramic junction. (*With reference to Eutech open pore electrodes EC620130, EC620131, EC620132 and EC620133.) This unique construction protects the electrode from clogging even in difficult samples. If used in combination with specially formulated electrolyte, the flow rate into the pore is faster and leads to better contact between the reference electrode and sample. This generates a shorter response time and more accurate measurements.

ORP or Oxidation Reduction Potential measurements are used to monitor chemical reactions or to determine the oxidizing or reducing properties of a solution. The ORP measurement can be made using the millivolt mode of a pH meter and are utilized very successfully in many commercial and industrial applications such as Cyanide Oxidation, Aquarium Monitoring, Chromate Reduction, Drinking
Water, Swimming Pool Water, Pulp Bleaching, Cooling Tower, Ozone Monitoring and Water Pollution Monitoring. ORP is also known as Redox Potential.

OUR or Oxygen Uptake Rate values are given in mg/L/hr and is usually applicable in the study of the concentration of micro-organisms.

Ozone – Ozone is one of the strongest and most rapid oxidisers and disinfectants available. It does not corrode nor cause scaling. In addition, ozone has no smell, does not cause skin nor eye irritation and does not pose a health hazard. Although more expensive than traditional disinfectants like chlorine and bromine, because it does not cause corrosion nor scaling, the long-term maintenance cost of a water system which uses ozone as a disinfectant may be reduced compared to using chlorine. Ozone is gaining popularity in top spas and certain swimming pools.

Polarographic Cell – consists of two electrodes placed in the electrolyte: One with fixed potential called the reference electrode, and the other with a variable potential called the polarizable electrode. As voltage is applied to the polarizable electrode, a redox reaction occurs, where electrons break away from the electrode to bond with oxygen in the electrolyte. The rate at which the electrons break away from the polarizable electrode is linearly proportionate to the amount of oxygen available in the electrolyte, hence this movement of electrons is representative of the amount of dissolved oxygen left in the electrolyte.

pH is the measure of H+ ion activity to determine acidity or alkalinity of test sample. In general pH 7 is neutral, below pH 7 is acidic and above pH 7 is alkaline. Theoretically pH curve is 0 to 14 pH.

pH Slope – is the voltage produced per pH and is theoretically 59.12mV per pH at 25 °C. However in practice it can be anywhere between 50 to 58 mV.

PWB or Pure Water Buffer refers to water with low ionic concentration.

Replatinising is necessary when the platinum-black layer of the Conductivity sensor wears off over time. The Conductivity section of the sensor consists of two platinum plates or wires that are plated with a layer of “platinum-black”. Usually this is a relatively soft layer and is required for stable, accurate measurements. In time, the platinum-black layer may wear off in some applications and the sensor
will require replatinising.

Resistivity – A measure of how strongly a material opposes the flow of electric current. A low Resistivity indicates a material that readily allows the movement of electrical current charge.

RJ45 or Registered Jack 45 is a physical interface often used for terminating twisted pair type cables. “RJ” stands for Registered Jack which is part of the United States Code of Federal Regulations. It has eight “pins” or electrical connections per connector. Common uses include internet and Ethernet cables. The CyberScan Series 6000 offers RJ45 connector for internet and Ethernet communication capabilities to conduct on-the-spot online research and access global email account.

RS232C – RS232C stands for Recommended Standard-232, A TIA/EIA standard for serial transmission between computers and peripheral devices (modem, mouse, etc.). Using a 25-pin DB-25 or 9-pin DB-9 connector, its normal cable limitation of 50 feet can be extended to several hundred feet with high-quality cable.

RTD or Resistance Temperature Detector refers to the measurement of temperature by measuring the change in electrical resistance across metal wires. This resistance value is interpreted by an RTD thermometer. Although the RTD wire can be made of any metal, platinum is preferred for its excellent repeatability, stability and resistance to corrosion and chemicals. RTDs are more accurate and stable compared to other probes such as thermocouples. However they are not recommended for extreme temperatures. An RTD probe is chosen where accuracy and repeatability are important.

Salinity – Salinity is the measure of amount of dissolved salts in sea water and results are reported in ppt(g/L) or %. Salinity Correction compensates the variations in oxygen solubility due to salt concentration in the sample. Self-Diagnostic Messages prompt and guide users with error message codes or graphical icons for easy meter troubleshooting.

Salinity Correction compensates the variations in oxygen solubility due to salt concentration in the sample.

Self-Diagnostic Messages prompt and guide users with error message codes or graphical icons for easy meter troubleshooting.

Soft Keys – Soft keys are located close to the screen-readouts that display the functions selected when the keys are pressed; commonly used on small devices with limited space such as handphones, PDAs and handheld meters.

SOUR or Specific Oxygen Uptake Rate indicates biological activity of microbes in the wastewater treatment process and the load placed on them. SOUR is the relationship between oxygen uptake and the amount of solids. SOUR values are given
in mg/hr/g.

Stability Function averages and displays indicator or icon whenever readings stabilise.

TDS or Total Dissolved Solids is measured in mg/L, parts per million (ppm) or parts per thousand (ppt).

TDS Conversion Factor is a factor for converting Conductivity to TDS value to best suit the
specific sample being measured (e.g. KCl = 0.5, 442 = 0.67 @ 25 °C).

Temperature Coefficient indicates the temperature influence in the chemical equilibrium (eg disassociation) of the solution due to non-linearity of intrinsic salt/chemical property varies from one sample to another (typically 2.1 %/°C at 25 °C).

Temperature Compensation is necessary as most electrochemical parameters (i.e. pH, Conductivity, DO) are temperature dependent and most applications require some form of temperature compensation to ensure standardized measured values. Please refer to the definitions for ATC
and MTC on page 113.

Thermistor – Thermistors are thermally sensitive resistors which change electrical resistance due to temperature changes. They have predictable characteristics and offer long term stability. Although response times are generally faster than other types of probes, thermistors have a limited temperature range that usually cannot exceed 150 °C.

Thermocouple – Thermocouple probes are composed of two dissimilar metals, joined to produce a voltage at a given temperature. Thermocouple thermometers measure, amplify, linearise and display the proportional voltage signal generated by the thermocouple probe. Thermocouples are used in most general purpose applications where precision is not a top priority. They offer a wide temperature range and come in a variety of metal combinations or calibrations.

Thermometry – Thermometry is the measurement of temperature or temperature changes. Temperature measurements are necessary in various industries ranging from agriculture, HVAC, chemical and manufacturing, food and beverage, boiler and cooling towers, schools and laboratories to water and wastewater treatment. There are various types of thermometers that rely on different principles of measurement.

Turbidity – Turbidity, measured in Nephelometric Turbidity Units (NTU), refers to the concentration of undissolved, suspended particles present in a liquid. It is a measure of sample clarity, not colour. The cloudier a sample, the higher the turbidity reading. High turbidity is caused by particles such as silt, clay, microorganisms and organic matter. By definition, turbidity is not a direct measure of these particles, but how these particules scatter light.

USEPA Method 180.1 – A regulatory method set by US EPA which requires the following to be included in the design of Turbidity meters: 1. Primary detector for nephelometric (90 degree) measurement; 2. Light source tungsten filament lamp (white light); 3. Spectral response peak for the detector between 400 and 600 nm, the primary wavelengths of light.


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