Product category:
Liquid Analysis: Titration, HPLC, IC
News Release from: Metrohm UK | Subject: 774 Oven Sample Processor and 831 KF Coulometer
Edited by the Processingtalk Editorial
Team on 28 April 2004
The determination of water in hair - the
easy way
With a unique technique developed by Metrohm, water in hair analysis times are shorter and the reproducibility of results is significantly better: plus the hair sample needed is tiny!
People expect a lot from shampoos and conditioners Unfortunately, it is not easy to tell a good shampoo from a poor one
This article was originally published on Processingtalk on 2 Jul 2008 at 8.00am (UK)
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Cost, fragrance, and lots of foam is what most people look for in shampoo products.
Lather and foam is of little importance, but they often get the most attention.
Foaming occurs when surfactant molecules gather around air instead of oil.
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The result is millions of tiny bubbles.
Obviously, the air bubbles are using the surfactants that should be removing dirt and oil.
We have all seen shampoo advertisements showing happy, beautiful people taking showers with their heads heaped high with mounds of lather.
These images have taught the public to associate lather with cleansing ability.
The truth is, lots of foamy lather only means too much shampoo was used.
Excess foam equals waste.
Sebum and other oils quickly destroy foam.
Ideally, the head should have just enough lather to lubricate the scalp and hair.
This will help your fingers massage the shampoo more effectively into the hair.
Fragrances and foaming qualities are not good ways to evaluate shampoos and conditioners.
A good way to evaluate the moisturizing performance of the shampoo and conditioners is to determine the water content of the hair before and after treatment with the relevant product.
A sample of hair is taken from the head prior to treatment.
The hair is then washed with the shampoo/conditioner, dried and a further sample is cut from the hair.
Fairly large samples of hair were taken.
Historically the analysis of water in hair was not only time consuming but very inaccurate.
The sample was typically digested with hot acid and then added to a solvent (typically methanol).
This sample solution was then injected into a volumetric Karl Fischer instrument where the moisture content was determined.
At every step errors were introduced and subsequently poor relative standard deviations were achieved on the results.
However, with a unique technique developed by Metrohm, analysis times are shorter and the reproducibility of results is significantly better.
Using the 774 Oven Sample Processor in conjunction with the 831 KF Coulometer analysis times are typically 3 - 5 minutes and RSD's on results are less than 1%, and more importantly for the hair donor, sample sizes are tiny!! The hair is weighed into a vial and the top is sealed (crimped).
This sample is then introduced into an oven where the water evolved is titrated in the KF coulometric cell.
The refined methodology of the 774 OSP brings decisive advantages, listed below.
Strictly reproducible analysis conditions for all samples, this is shown by the considerably improved precision of the results.
Manual sample preparation is reduced to a minimum, just "weigh, crimp and analyse".
Considerable savings in time and money, less reagent costs for example, no more acid and solvent extraction.
No contamination of the oven, consequently there is no carryover and memory effects.
Improved water release from the sample as the carrier gas does not just pass over the sample but directly through it.
Fast analysis times; typically 3 minutes, and up to 35 samples at a time!.
We also have applications where the bound and unbound moisture can be determined separately. Request a free brochure from Metrohm UK ...
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