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Hot Topics in Analytical & Chromatography - December 2009
In this issue, we address the following topics:
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 Green Karl Fischer Titration: Impact on health and growing environmental awareness has created concerns about handling reagents with toxic components. The need to reduce workers’ exposure to hazardous substances is in greater demand than ever before.
With the goal of improving laboratory safety and reducing environment toxicity, Fluka now offers the HYDRANAL®-E reagent line for reliable Karl Fischer titration without using toxic compounds.
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Features and Benefits of Karl Fischer titration with non-toxic ethanol-based E-type reagents:
- Reduced toxicity over methanol-containing reagents
- Better solubility of hydrophobic samples
- Additives increase reaction rate and conductivity of ethanol (patent-protected by EP 0 933 634 and JP 4440362)
- Several ketones can be titrated without side reactions
- Pyridine-free, similar to all HYDRANAL reagents
- Suitable for both volumetric and coulometric KF titration
- Possible replacement for most methanolic KF methods
- Compatible with all titration equipment
- End-point color appears visually more intense compared to methanolic titrations
- Users fulfill requirements of DIN EN ISO 14001
Additional Information:
- Visit the HYDRANAL E-types web page to review the application list and find out how you can eliminate toxic reagents from your KF application.
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 Cyanides by UV/Vis Spectroscopy: Cyanides are extensively used in many industrial processes; hence, they frequently occur in toxic waste and wastewater of diverse origin, also in streams that receive uncontrolled and unpurified industrial effluents. The maximum contaminant level (MCL) has been set at 0.2 ppm because EPA believes, given present technology and resources, this is the lowest level to which water systems can reasonably be required to remove this contaminant should it occur in drinking water. Above this level, cyanides in drinking water pose a health risk.
Sigma-Aldrich’s new indicator for photometric determination of cyanide exhibits a linear working range from 10-6 to 10-5M, and is therefore sufficient to monitor micromolar concentrations of cyanide. The detection limit for the sensor is 1.0 x 10-6 M, fully meeting the U.S. EPA water quality criterion of sensitivity below 0.2 mg/L. The indicator has a very fast response, within 30s, which can also be detected by the naked eye.
5a,6-Dihydro-5a,6,6-trimethyl-2,8-dinitro-12H-indolo[2,1-b][1,3]benzoxazine (Fluka 94979)
Reagent for photometric determination of cyanide, ≥96.0% (HPLC), 100 mg
Additional Information:
- New Reagents for UV/Vis Spectroscopy (Analytix journal 4/2009, page 10)
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 Nitrate Detection using ISE: Nitrate is one of the most commonly analyzed substances in environmental, food and many other types of samples. In drinking water, nitrate is a major health concern because of its toxicity, especially to young children.
EPA's maximum contaminant level (MCL) for drinking water is set at 10 mg/L. In wastewater treatment plants it is essential to monitor the nitrogen removal. The ion-selective electrode (ISE) is an EPA-approved method for the test procedure to directly read nitrate in wastewater.
Sigma-Aldrich has introduced a newly developed nitrate ionophore, which has superior characteristics over all other nitrate ionophores. Membrane electrodes prepared with the new function-tested ‘Nitrate Ionophore VI’ from Fluka exhibit a greatly increased lifetime and lower detection limit than any other nitrate-selective electrodes on the market.
Nitrate Ionophore VI (07295)
SelectophoreTM, function tested; available in 10mg, 100mg, or 500mg pack sizes
Additional Information:
- View Product Data Sheet for Nitrate ionophores
- To see all available Selectophore ionophores, including ISE reagents and accessories, visit: www.sigmaaldrich.com/selectophore
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