Elemental Analysis Service Heriot Watt University Christina Graham.
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Transcript of Elemental Analysis Service Heriot Watt University Christina Graham.
Elemental Analysis Service
Heriot Watt University
Christina Graham
What is Elemental Analysis?
Elemental analysis is the determination of the percentage of an element in a sample
Our instrument the CE 440 analyses for the elements carbon, hydrogen, and nitrogen
Other elements can be done externally
Schematic DiagramExeter CE-440 Elemental Analyser
O
He
2Combustion Reduction Mixing
Area
SampleVolumeDetectors
Tube Tube
How will the service operate?
One day a week All samples submitted the previous
day in the sample bottle provided All samples accompanied by a
completed request form Results and sample returned to you
the next day
Risk / Hazard assessment Please specify if sample is harmful (specify) /
volatile / hygroscopic / air sensitive / scarce / etc.
%C
%H %N
Formula
Theoretical Information
* Please draw approximate structure * on reverse side of submission form
Date of Analysis Operator
Results
Comments
Assay No.
%C %H %N
Name User / Sample Code
Supervisor
Department
Telephone
E-mail Date Submitted Tick box if duplicate analysis is required
General Information
* Users outwith the University should * specify the company and address on the reverse side of submission form
Christina Graham, Elemental Analysis Service, Department of Chemistry, Heriot-Watt University, Edinburgh, EH14 4AS
Tel 0131 449 5111 Ext.4233, E-mail [email protected]
Elemental Analysis Request Form Department of Chemistry Heriot- Watt University
Project Code
Request Form
Your sample code should consist of your initials and a number that refers to an individual sample.
Give the formula or at least an indication Deduce your %CHN content It is very useful draw the structure on the
back of the form It is essential to complete the hazard
assessment
How much sample do I need?
If your hydrogen content is <3%3.0mg
If your hydrogen content is >3%2.0mg
Samples having a large residue of the order 50% - up to 5mg
Excess sample is always returned
Good Working Practice
Ensure that your sample is as pure as it can possibly be
Sample must be free from solvent
Submit samples regularly and on time
Make sure you hand in enough sample
Solvent Purity
Example - A sample of phenyl hydrazine (1.6mg) containingapprox. 2% w/w methanol.
C6H5NHNH2 - 108.14 g/mol
1.6mg 'sample' is actually -1.568mg Phenyl hydrazine (1.450 x10-2 mmol)
0.032mg MeOH (9.988 x10-4 mmol)
Theoretical formula - C6H8N2Actual formula - C6H8N2. 0.069MeOH = C6.069 H8.276 N2O0.069
%C %H %NTheoretical 66.62 7.47 25.91Actual 66.04 7.57 25.39
Elemental Analysis Total Usage Jan 2000- July 2004
Total
0
50
100
150
200
250
Jan May Sep Jan May Sep Jan May Sep Jan May Sep Jan
Take care and try to get it right first time!!
For publishable results each element must be within + 0.3%
If sample result is poor you would have to re-purify, dry and resubmit
this costs time, money and is unfair to others
Some points to note
Cost of an internal sample is £3 Cost of an external sample is £9 - £15
for a duplicate Keep a note of your sample code and
assay number - a computer record and hard copy will be kept for 5 years
Online help
Home page is http://www.che.hw.ac.uk/research/services/chn.html
%CHN calculator Solvent correction calculator On-line request form
Please don`t say to me!! Sample is totally pure
as the NMR is perfect Is the instrument
working properly? Urgent sample - only
10 of them! Not too worried about
the result - just a quick check I have the right stuff!!!
Good Luck with your research!!!
Looking forward to analysing your samples!!!
Thank you for your time today!!!!