Product category:
Liquid Analysis: Titration, HPLC, IC
News Release from: Metrohm UK | Subject: 662 Photometer
Edited by the Processingtalk Editorial
Team on 20 January 2004
Magnesium determination by photometric
titration
Magnesium carbonate is added to cooking salt as an anti-caking agent and as an aid to improve the flow characteristics of table salt: these levels of magnesium can be determined photometrically
Magnesium carbonate is added to cooking salt as an anti-caking agent and as an aid to improve the flow characteristics of table salt Many doctors and health experts believe high levels of salt (in particular the sodium part of salt) in diets can contribute to hypertension (high blood pressure)
This article was originally published on Processingtalk on 5 Jan 2007 at 8.00am (UK)
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Photometric measurements and titrations
Photometric indication using the Metrohm 662 Photometer can bring an improvement in the detection of the end point of titration procedures, eliminating human and lighting variation factors
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With this in mind many companies are producing so called "low sodium salt" that do (as the name suggests) have lower levels of sodium but can contain as much as 17 percent magnesium salts.
These levels of magnesium can be determined photometrically with the use of a photometer and an autotitrator.
The sample is weighed into a beaker and 10ml of NH3/NH4Cl buffer is added along with 80mls of distilled water.
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1 ml of methylthymol blue salt colour indicator is added and the solution is then titrated with 0.1 mol/L EDTA.
The 662 Photometer is a compact, microprocessor-controlled instrument that is very versatile and has many applications.
It has been developed for direct photometric measurements and the photometric endpoint determination of titrations.
The features of this unit are listed as: very easy to use; display of transmission, absorption and concentration.
Transmission and absorption are the traditional measured quantities.
The 662 Photometer offers the additional possibility to determine the concentration of sample solutions after previous calibration.
The optical and electronic stability as well as the noise characteristics are excellent; even difficult measuring problems pose no major difficulties.
The measured value can be compensated such that also titrations with very small signal changes can be safely evaluated.
Measurements can be performed in any sample container, be it a beaker, a test tube, a titrating vessel, etc The long, flexible light guide is just as convenient to use as a pH electrode; its resistance to solvents is excellent, with a wide wavelength range.
The whole visible region (including white light) is available without any gaps; there is no restriction to just a few spectral regions.
Thanks to the continuous wavelength scale with stepless adjustment, measurements can always be performed at the point of maximum absorption.
Accordingly, there is no loss of sensitivity due to non-optimal selection of the wavelength.
Expensive optical cuvettes are no longer needed: the long, flexible glass-fibre light guide of the 662 Photometer makes photometric determinations just as easy as, e.g, a pH measurement in a wide range of different vessels and over the entire visible wavelength range (400 - 700 nm).
For photometric titrations we recommend the 662 photometer in conjunction with our Titrando range of titrators. Request a free brochure from Metrohm UK ...
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