Stop! Don’t drink that water. Check out this brief article on Water Testing.

November 6, 2009


Water testing is the continous sampling of various liquid streams and the analysis of their quality. These liquid streams include watercourses such as rivers and lakes, groundwater, recirculated cooling streams, boiler feedwater or condensate, and process effluents.

Water testing is not only a vital element of preserving a safe public drinking supply and a healthy environment, it can also improve industrial process efficiency for better products at reduced cost.

Our selection of water testing equipment includes test kits for bacteria and chemical compounds; colorimeters; multiparameter meters for measuring pH, ORP, conductivity/ salinity/total dissolved solids (TDS), dissolved oxygen (DO), and temperature; and turbidimeters.

Bacterial Test Kits

Eliminate time-consuming culture/plating techniques for convenient bacterial counts and assays.

Colorimeters

Measure the light absorbed by your sample after it reacts with a reagent that produces a color change. Since the intensity of absorbed light is proportional to the concentration of the compound, colorimeters accurately indicate the concentration of various compounds in your sample. Many colorimeters work with specific test kits for easy analysis. This reduces operator error, whether in reading color changes or in measuring reagents.

Multiparameter Meters

Measure pH, ORP, conductivity/salinity/total dissolved solids (TDS), and/or dissolved oxygen (DO)/biological oxygen demand (BOD).

Test Kits for Chemical Compounds

Contain prepared reagents and standards that let you easily determine the concentration of specific compounds in the sample. We offer titrimetric and colorimetric test kits for several compounds including ammonia, chlorine, carbon dioxide, heavy metals, and many others.

Colorimetric test kits:  These tests determine the concentration of a substance. The higher the concentration of a substance, the darker the color developed in the test.

Other elements can interfere with the accuracy of the tests. Read kit instructions for appropriate adjustments.

Titrimetric test kits: The concentration of a substance in a sample solution can be determined by titrimetic tests. After the sample is treated with an indicator, a standard titrant is added until a color change indicates a completed reaction. The amount of titrant used coresponds to the concentration of the substance being tested.

Turbidimeters

Turbidity in water is caused by suspended and colloidal matter such as clay, silt, finely divided organic and inorganic matter, and plankton and other microscopic organisms.

Quantify the turbidity of your sample by measuring the light scattered at a 90¡ angle to a source light beam. The meter compares the light scattered by sample particulates to light-scattered in a fluid with known turbidity and displays the measurement in nephelometric turbity units (NTU). The presence of dissolved, color-causing substances that absorb light may cause a negative interference.

Turbidimeters with scattered-light detectors located at 90° to the incident beam are called nephelometers. Nephelometers are relatively unaffected by small differences in design parameters and therefore are specified as the standard instrument for measurement of low turbidities. Poor measurement technique can have a greater effect on measurement error than small differences in instrument design.

Determine turbidity as soon as possible after sample is collected to ensure examination under original conditions.

  1. Gently agitate samples to ensure a representative measurement. If storage is required, cool to 4°C to minimize microbiological decomposition of solids.
  2. Keep cells scrupulously clean, inside and out, and discard if scratched or etched. Never handle them near the instrument’s light beam.
  3. Fill cells with samples and standards—allow sufficient time for bubbles to escape. Because small differences between sample cells can significantly impact measurement, use either matched pairs of cells or the same cell for both standardization and sample measurement.

Coagulation-Flocculation Jar Test of Water: This is a general procedure for the evaluation of a treatment to reduce dissolved, suspended, colloidal, and nonsettleable matter from water by chemical coagulation-flocculation, followed by gravity settling. The practice provides a systematic evaluation of the variables normally encountered in the coagulation-flocculation process. The coagulation-flocculation test is carried out to determine the chemical, dosages, and conditions required to achieve optimum results. The primary variables to be investigated using the recommended practice include, (but are not limited to): chemical additives, pH, temperature, and the order of addition and mixing conditions.

Significance: This jar test permits the evaluation of various coagulants and coagulant aids used in the treatment of water and waste water for the same water and the same experimental conditions. The effects of concentration of the coagulants and coagulant aids and their order of addition can also be evaluated by this practice.

View our complete selection of Water and Industrial Liquid Sampling products.
View our complete selection of Water Purification products.
View our complete selection of Water Testing products.

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Biowarfare Threat Detection

November 4, 2009

It’s 7:45 a.m. Just your average Tuesday morning. You’re waiting in line for the coffee machine at work when the sudden shriek of a fire alarm splits the air. A puff of white powder from an envelope in the mail room across the hall has coworkers streaming out the exits as a call goes out to the local emergency response team. It will be up to these first responders, with their handheld bioagent detection devices, to determine if this scare is a hoax or the real deal.

Biowarfare Agent Detector

 

Biowarfare agent detection kits have become one of local government’s most coveted weapons in the war on terrorism. They are carried by emergency units likely to be first on the scene—from fire departments, police and sheriff’s personnel, emergency medical teams and HAZMAT units, to Federal emergency management teams and privately hired corporate security professionals. They are designed to address the second step in a biowarfare incident response: identifying whether there is a credible threat posed by the incident while field samples are sent to a lab for next-day confirmation.

 

A credible threat is defined as the presence of a biowarfare agent in sufficient quantity to represent a threat to people who come into contact with the substance. A single infectious dose (I.D.) of anthrax is approximately 10,000 spores, or 10 nanograms, which is about 1/100th the size of a single speck of dust. Clearly, locating this amount in an average size room is virtually impossible. However, in the case of actual bioterrorism activity to date, as well as the many thousands of hoax incidents that occur much more frequently, the amounts used have been much larger. For example, the letter sent to Senator Daschle’s office in October 2001 contained approximately 2 grams of material, the equivalent of about 200,000 infectious doses.

 

To ensure accuracy of results, detectors such as the new BioWarfare Agent Detection Device (BADD™) carried by Cole-Parmer, are rated to detect at least 1/4 of a speck of dust (250 micrograms) and have been found capable of identifying anthrax spores in amounts as small as 1 nanogram, or 1/1000 of a speck of dust without generating false positive results from “close cousin” bacteria such as Bacillus globigil.

 

These self-contained, first response kits operate much like a home pregnancy test. They rely on a simple swabbing of the suspicious powder or liquid, which is then diluted with a special diluent and placed, in droplets, into a self-contained cassette-type test strip. The results, positive or negative, are available and visible to the human eye in three to 30 minutes, depending upon the concentration of the sample tested.

 

In the case of the BADD detector, which is capable of testing for ricin and botulinum toxins, and three strains of anthrax (Ames, Vollum, and Sterne), two test lines containing antibodies specific to the biowarfare agent being tested for “light up” when the agent is present in the sample—thus signaling a “positive” reading. If only one “control” line appears in the detection device window, it signifies a “negative” reading.

 

Although not as sophisticated as the $10,000- to $100,000-per-unit electronic reader systems used by the military and others, these sensitive test kits are easily transported, and provide all necessary materials to collect and test multiple samples in the field. Moreover, at roughly $50 per test, they are reliable and cost-effective, allowing wide deployment and use at minimal cost.

 

[As for the Federal government's recommendations, recent guidelines from the General Services Administration targeted specifically for mail handling at Federal agency mail rooms stated that handheld assay tests may produce unreliable results in certain circumstances and recommended that all samples be sent to certified laboratories for processing. However, as of August 2, 2002, the International Association of Fire Chiefs (IAFC) withdrew its support of the ban, and directed fire departments and other first responders to follow the Centers for Disease Control guidelines for handling potential exposure to anthrax, and strongly advised fire departments to not rely solely upon handheld devices. These guidelines are consistent with the recommendations of all the major field detection device manufacturers.]

 

View our complete selection of Bacteria test kits
View our complete selection of Biowarfare Agent Detection Devices (BADD)

 

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Posted by Cole-Parmer

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