ICP-Optical Emission Spectroscopy
(Perkin Elmer Optima 7300DV)
Sept 2010
ICP-OES Sample Preparation
1.
Completely dissolve solids (including nanoparticles) in your samples into aqueous solutions
and/or filter to remove solids (pore size of 0.45 µm or less). Samples containing biological
matter or polymers should be digested with concentrated acid AND hydrogen peroxide.
(See page 24-25 for more information on digestions.)
2.
Use 1% nitric acid (trace metal grade, ≤1ppb) to dilute your samples and standards and
prepare a blank solution of just 1% nitric acid. Samples should be diluted to a final
concentration of acid of less than 5%. If you are not diluting your samples, or your dilution
factor is less than 1:5 please speak with the instrument manager about sample preparation
methods.
3.
Use HDPE or LDPE bottles for long-term storage of solutions. The NRF will not be
responsible for any contamination issues resulting from improper storage.
Start-up
• Open the software “WinLab32”
• Click on “Plasma” icon
 If plasma is off check if spectrometer is
ready (open “System → diagnostics”, and
click on “Spectrometer” tab)
If not ready, find the instrument manager
immediately.
 If plasma is on, skip to “Tuning”
3
Start-up – cont.
• Stretch tubing so plastic tabs fit in slots on both sides of the pump and
clamp the tubes in place on the pump making sure each tube fits in the
groove of the corresponding clamp. Sample tubing has black tabs and drain tubing
has red tabs.
• Check to make sure the sample will flow into the spray chamber and that
the waste (drain tubing) will flow out of the spray chamber. (The pump rotates
clockwise.)
• Immerse sample tubing into acid solution (1% nitric acid)
4
Start-up – cont.
• Turn on the plasma by clicking on “plasma  on”
• When the plasma lights you will see a green glow in the shielded window
• Check to make sure that the sample line is flowing into the spray chamber
(can lift the line out the solution to introduce an air bubble) and that waste is flowing
out of the bottom of the spray chamber through the drain tubing (if the spray
chamber is not properly drained the plasma will shut off)
If the flow directions are not correct turn off the plasma and fix the tubing positions before restarting
the plasma
• Wait for 30 minutes for the instrument to warm up, you may make or edit a
method during this time
5
Tuning
•
•
•
•
•
Immerse sample tubing into Mn Solution
Open “Tools → Spectrometer Control”
Click on “Hg Realign” and press “OK”
Wait till Spectrometer window shows “Hg Lamp Off”
Immerse sample tubing into acid solution
6
Method
• Go to “File → New → Method” and press “OK” in “Create New Method”
window or go to “File → Open → Method” and choose your method
7
Method – cont.
• Set “Spectrometer”
• Define Elements: click on empty cell, click on “Periodic Table”, select
element from the table, click on “λ Table”, highlight desired
wavelengths, and press “Enter Selected Wavelengths in Method”,
repeat for all elements of interest
8
Method – spectrometer cont.
•
•
Settings: set “Time(sec)” as min of 5 and max of 20 and “Replicates”
as 3
Spectral Windows: default
9
Method – cont.
• Set “Sampler”
• Plasma: set “Plasma Conditions” as “Same For All Elements”
and select “Plasma View” as “Axial” for samples with low
concentration and “Radial” for samples with high concentration
(Speak with the Instrument Manager if you have a broad concentration range
and need to use the plasma condition “vary by element”)
• Peristaltic Pump & Autosampler: default
10
Method – cont.
• Set “Process”: default
• Set “Calibration”:
• Define Standards: name IDs for blanks and standards, you
should have one Calib Blank and several Calib Stds
• Ignore “A/S Location”
11
Method – calibration cont.
• Calib Units and Concentrations: change units and set standard
concentrations, use 2 – 3 standards per order of magnitude in
concentration (0-1, 1-10, 10-100)
12
Method – calibration cont.
• Blank Usage: select blank solution from the list
• Equation and Sample Units: change units to same as calibration
and choose a line type
• Others: default
• Set “Checks” and “QC”: default
• Set “Options”: check “Start each sample on a new page” and
“Detailed Cal Summary”
13
Method – cont.
• Open “Edit → Check Method”
• If method has no errors go to “File → Save as → Method” and
name the method
• If method has errors go back and correct the reported error
14
Sample Info
• Open “File → New → Sample Info File”, and name your
samples
• Open “File → Save as → Sample Info File” and name the
sample information file
15
Calibration
• If using an old method go to “File → Open → Method”, and select the
method
• If using an old sample information file go to “File → Open → Sample
Info File”, and select your sample file
• Click on “Manual” icon
• In “Results Data Set Name” enter a new data set
name or open an old dataset, select “Save Data”
and “Print log”
• Immerse sample tubing into blank solution
16
Calibration – cont.
•
•
•
•
Click on “Analyze Blank” (view report via “Results” or the PDF file)
Immerse the sample tubing into standard solution
Click on “Analyze Standard”
Repeat for all standards, the drop down list indicating the standard
name will automatically update
• View calibration results by clicking on “Calib” tab
17
Measurement
• Immerse the sample tubing into sample solution
• Name sample ID if not using a sample info file, if using a sample
info file the ID will automatically update
• Click on “Analyze Sample”
• View report via “Results” or the PDF file
• Save results in PDF format in your folder in
the C drive “user data” folder
See page 20-23 for information on data reprocessing and
exporting to excel.
18
Shut-down
• Wash the system: immerse the sample tubing in acid solution for 10
min and then in water for 5 min
• Take the sample tubing out of solution, put it in the empty tube, and
wait until the spray chamber is dry (no more bubbles leave the bottom of the
spray chamber)
• Click on “Plasma”, and turn off plasma by clicking on “off”
• Unclamp and loosen the sample and drain tubing
19
Data Reprocessing
•
•
Reprocess data after making adjustments to your method (you can change your calibration line type, remove
standards, remove internal standard weighting, etc… but must save the method as the same name for reprocessing to work
correctly)
Click on the “Reproc” icon click “Browse” by “Data Set To Reprocess” and highlight your data
set  click “Ok”
20
Data Reprocessing
•
•
•
Click “Browse” by “Reprocessed Data Set” and name the reprocessed data file
Check “Print Log” and “Save Reprocessed Data”, uncheck all other boxes
Highlight your blank, standards, and samples  click “Reprocess”
21
Data Export
•
•
Go to the computer desktop and open “Data Manager” software
Highlight the dataset you want to export and click the “Export” icon
22
Data Export
•
•
•
In the Data Export Wizard click “Use Existing Design”  open “Basic export.xpt” or your own
design
Click “Finish” to go directly to the export step or click “Next” to modify the design
If you clicked “Finish”  click “Export Data” click “Finish”  data will be saved in
C:\userdata\Data Manager Export\dataset name
23
Digestion Methods
• Nitric acid is typically the primary component of acid digestions.
• Hydrochloric acid is useful as a complexation reagent for
precious metals. HCl should always be used when Ag or Sb are
analytes of interest to ensure good recovery.
• The use of hydrogen peroxide enhances the oxidation
properties of nitric acid especially in the digestion of organics.
Caution should be used when digesting with peroxide as it
increases reactivity.
!! IMPORTANT : Hydrofluoric acid (HF) should NOT be used for
digestion of materials to be analyzed by ICP-OES as the torch,
spray chamber, and nebulizer are quartz. !!
1.
2.
3.
4.
5.
Place up to 1.0 g (or up to 1 mL) of sample into each reaction vessel.
Add 9 mL of nitric acid to each vessel.
Add hydrochloric acid and/or hydrogen peroxide and allow to react for 1 minute.
Heat reaction vessels to 180°C over 5-10 minutes and hold at 180°C for another 10 minutes to 1 hour.
Allow to cool then dilute with ultrapure water to an acid content of 5% or less.
24
Digestion Methods – Application Notes
• Always use extreme caution and wear protective gear when performing digestions!
• If the amount of sample is limited scale down the amount of acid and peroxide proportionally.
• Never fill a reaction vessel more than half way! Overfilling may cause unsafe pressure levels in enclosed
vessels or bubbling over in open vessels. This is especially true when hydrogen peroxide is used.
•The amount of time you heat a sample depends on your heating method and your sample.
• Microwave or oven digestions systems usually require 10-30 minutes of heating.
• Hot block or hot plate digestions usually require 30-60 minutes of heating.
• The type of reaction vessel depends on your heating method.
• For microwave or oven digestions use the appropriate sealed vessel, usually teflon.
• For hot block digestions use glass or plastic tubes manufactured specifically for digestions. Do not cap or seal tubes!
• For hot plate digestions use heavy duty glass erlenmeyer flasks. Do not cap or seal flasks!
• If your sample still has solid particles in it after digestion:
• If you require a complete digestion you may need to use a smaller amount of sample or heat your sample longer.
• If you do not require a complete digestion you should dilute your sample, centrifuge it, carefully remove the supernatent,
and then filter the supernatent to be used for analysis using 0.45 µm, or smaller, pore size filters.
25