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Posts Tagged ‘water testing’

Hey Genius, Take our Tech Challenge on Chemical Testing

Posted by Cole-Parmer on February 5, 2010

Challenge: The U.S. EPA was testing rivers and lakes for chemical levels. The technician detected above-regulation levels in Lake Somhe, including phenol, toluene, mercury, oils, and more. There are a dozen different factories and pipelines which empty into Lake Somhe, and the EPA needs to determine which of these sources is contributing to the unacceptable chemical levels before doing a more in-depth analysis at the individual site.

The EPA contacted Cole-Parmer to find instruments or tests that can help them quickly and easily determine which sites are causing the problem.

Which test would be most effective for their purpose?

  1. Recommend a chemical classifier which work similar to a pH paper strip.
  2. Suggest the technician start with a colorimeter to determine phenol and toluene levels.
  3. Suggest a gas chromatograph and mass spectrophotometer to determine phenol and toluene levels.
  4. Have the EPA collect samples from each site and send to an independent testing laboratory.

See the answer.

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

Posted by Cole-Parmer on 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.

Related Articles

Good Laboratory Practices for Taking Turbidity Measurements
Water Purification

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Pimp your CSI DNA Lab, yo. Check out this pimpin microcentrifuge.

Posted by Cole-Parmer on October 16, 2009

 

Thermo Scientific Heraeus Pico 21, 24-place microcentrifuge

Thermo Scientific Heraeus Pico 21, 24-place microcentrifuge

 

Abstract
Searching for environmental microorganisms (i.e., organism mining) is a very common process today and there are many commercially available kits for the detection of DNA in soil and water. The readily available kits minimize process preparation time and the need for on-hand reagents and consumables. The end user only needs to provide pipettes and a microcentrifuge. The Thermo Scientific Sorvall 24-place microcentrifuge was selected for this application to demonstrate how easy it is to use a soil DNA isolation kit in this Thermo Scientific Sorvall microcentrifuge.

The effective performance of the Sorvall 24-place microcentrifuge is representative of our entire new line of microcentrifuges, which includes the Heraeus Pico 21, Heraeus Fresco 21, Sorvall Legend Micro 17, Sorvall Legend Micro 21, IEC Micro 17 and IEC Micro 21.

Harvested soil samples were isolated following the FastDNA SPIN Kit instructions step by step. Gel results show clear extracted DNA which will then be subjected to further downstream analysis for identification. Harvested DNA are typically further analyzed to match for known organisms or new organisms.

Materials and Methods
Soil cores were collected from the Cataloochee plot in the Great Smoky Mountains National Park in March 2006. The plot was located and sample areas identified by their GPS coordinates using a hand-held GPS device. A clean metal corer was used to obtain 100 mm long soil cores1 with minimal disturbance to the site.

Soil cores collected at these sites were held at ambient temperature during transport to the Department of Biology at the Asheville, NC campus of the University of North Carolina (UNCA) and held at ambient temperature until use by microbiology lab students. All samples were used within three days of collection.

1. Samples containing 2.5 g of wet soil were diluted into a 22.5 ml sterile 0.8 % sodium chloride solution and incubated with shaking for 15 minutes; larger particles were allowed to settle out for 2 minutes.

2. Saline above the soil layer was serially diluted using sterile water.

3. Then, 0.1 ml dilutions were plated on solid microbiological media.

4. Plates were incubated at ambient temperature for seven days.

5. Isolated colonies were streaked on fresh plates to obtain pure cultures.

6. Colony and cellular morphologies were recorded for pure cultures.

7. DNA was isolated from pure cultures using a FastDNA SPIN Kit for soil (Qbiogene). The procedure was followed per the FastDNA SPIN Kit instructions. All centrifugation steps were performed using a Thermo Scientific 24-place microcentrifuge.

8. rDNAs of the resulting DNA samples were amplified by PCR with universal primers.2

Results
Post PCR, rDNA isolates were successfully visualized using electrophoresis in 1 % agarose gels (Figure 1). DNA isolates were subjected to further downstream analysis for identification.

Lanes 2, 3, 4, 5      

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Figure 1. Lanes 2, 3, 4, and 5 are PCR products from DNA samples prepared using the FastDNA SPIN Kit for soil (Obiogene) and Thermo Scientific 24-plce microcentrifuge.

Conclusion
Our full line of 24-place microcentrifuges is ideal for today’s busy labs using FastDNA SPIN Kits for isolation of rDNAs. These microcentrifuges have simple-to-use user interfaces with easily understood icons and a brightly lit display. Those features plus the snap-on bio-containment (Click-Seal) lid make this line of microcentrifuges a perfect choice for the multi-user lab.

The Thermo Scientific Heraeus 24-place microcentrifuges are small and quiet, making them easy to place in a busy setting without interfering with valuable bench space or the work process. They are valuable tools for all laboratories.

Shop: http://bit.ly/1M7bap

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