ICP-Mass Spectrometry
(Perkin Elmer ELAN DRC II)
JAN 2013
ICP-MS User Procedures
•
•
Users must sign in and sign out of the log book.
Users must be present for analysis of all standards. If the data does not look good (high RSDs, erratic
internal standard intensity, or standard concentration not with 10% of expected concentration) “pause”
the run and contact the instrument manager.
•
Users should check on the progress of sample analysis at least once every hour.
1. Is the plasma on?
2. Is the autosampler moving?
3. Is the pump tubing connected and not jerking?
4. Is the internal standard intensity stable and similar to previous samples?
5. Is the RSD greater than 0% and less than 10%?
*If the answer to any of the above questions is NO “pause” the run and contact the instrument manager.
•
ANY and ALL problems (including an initial smarttune failure or misplaced pump tubing) should be
recorded in the log book with a description of the problem and solution.
•
In the case of any problem during a run “pause” the analysis and contact the instrument manager. DO
NOT attempt to fix or clean the instrument yourself! (Exception: misplaced pump tubing may be
adjusted by the user.)
*Repeated failures to follow these procedures will result in loss of instrument privileges and the
user will be required to attend a re-training session before instrument access is restored.*
ICP-MS 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 25-26 for more information on digestions.)
2.
For ICP-MS the total dissolved solids (TDS) in the sample to be analyzed should be less than 0.1% (by mass). This
includes constituents in your sample matrix in addition to your analytes. Take the concentration of element or
chemical x molecular weight ÷ density of water x 100 and sum all constituents.
Example: Lead (analyte) solid is dissolved in a 1M NaCl solution (matrix). The maximum possible lead concentration is 0.5 mM. The
samples must be diluted by a factor of more than 50 to meet the TDS limit as the %TDS in the samples is 5.86%.
0.5mmolPb 207.5gPb 0.001mol
L



 100  0.01%
L
molPb
mmol
1000gwater
1molNaCl 58.5 gNaCl
L


 100  5.85%
L
molNaCl 1000gwater
3.
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 1:10 please speak with the instrument manager about sample
preparation methods.
4.
The concentration of analyte in your samples should be less than 200 ppb for ICP-MS. Please use ICP-OES for
samples with higher concentration. If the concentration in your samples is unknown use ICP-OES for screening or
prepare a series of sample dilutions from 1:10,000 to 1:10 to run on ICP-MS, starting with the largest dilution factor.
5.
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
• Turn on the water recirculator
located behind the computer
• Open the software “ELAN”
• Click on “Instrument” icon
 Check if vacuum is on (green), and if
Ar gas and water flows are normal
(green)
water
If not, find the instrument manager immediately
vacuum
Ar
gas
plasma
4
Start-up – cont.
•
•
•
Stretch pump tubing so plastic tabs fit in slots on both sides of the pump and clamp the
three tubes in place on the pump making sure each tube fits in the groove of the
corresponding clamp. Sample tubing has black tabs, internal standard (int std) tubing has
orange and blue tabs, and drain tubing is large diameter with black tabs.
Check to make sure the sample and int std will flow into the spray chamber and that the
waste (drain tubing) will flow out of the spray chamber. (The pump rotates counterclockwise.)
Immerse sample and int std tubing into nitric acid solution (1% HNO3)
5
Start-up – cont.
• Turn on the plasma by clicking on “plasma  start”
• During the “ignition sequence” the plasma indicator will turn yellow,
when the ignition sequence is done the plasma indicator should be
green and there will be a glow from the sample introduction area
If the plasma does not light or goes out immediately check to make sure that no areas of
the instrument are red or yellow and try again (up to 3 times), if there are red or yellow
indicators or if the plasma will not light after 3 times contact the instrument manager
plasma
6
Start-up – cont.
• Check to make sure that the sample and int std lines are flowing into the
spray chamber (can lift the lines 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
 Open your dataset by clicking on “Dataset” then “File” Open your
dataset.
7
Tuning
• Immerse sample and int std tubing into Smart Tune Solution
• Click on “SmartTune” icon
• Go to “File”  “Open” and select “SmartTune Daily your name.swz”
8
Tuning – cont.
• “ Optimization” Click optimize . Click “OK “
• Save tuning results in PDF file in “C:\User Data\Smarttune results”
with date and time in the file name
• View the report by clicking on “RptView” icon
If it passes, go to the next stage “Method” (page 11).
9
Tuning – Cont.
 If Daily performance fails the software automatically runs Autolens, Nebulizer Gas
Flow and Daily performance check.
 If second time Daily performance check passes you can go to method (Page 11)
 If it fails Ask instrument manager
10
Method
 Immerse sample and int std tubing into acid solution
• Click on “Method” icon
• Go to “File  New” and select “Quantitative Analysis” or go to “File 
Open” and choose your method
11
Method – cont.
 Set “Timing”
• Sweep: 50; Reading/Rep:1;Replicates: 3-5 (speak to Instrument Manager before
changing)
• Define “Analyte” by clicking in a blank cell in the “Analyte” column, right click to
bring up the periodic table and select element and isotope and click “Ok”, repeat for
all analytes and desired isotopes of an element
12
Method – set timing cont.
 Choose an int std and input it as an “Analyte” (the int std should have a
similar mass to your analyte/analytes of interest)
• Highlight the rows containing analyte elements and int std
elements
• Go to “Edit  define group” (a gray bracket will appear in the “Int Std”
column around the group)
13
Method – set timing cont.
• Highlight the row with the int std element
• Go to “Edit  set internal standard” (an arrow will indicate which
element has been set as the int std)
You may use multiple int stds for different analytes by defining multiple groups.
14
Method – cont.
 Set “Processing” and “Equation”: default
 Set “Calibration”
•
•
•
•
Choose a “Curve Type” by right clicking, use Linear Thru Zero or Wt. Linear
Change Sample Units to “µg/L or ppb” by right clicking on the cells in the “Sample
Units” and “Standard Units” columns
Set 2-3 standards per order of magnitude (0-1, 1-10, 10-100) with their defined
concentrations
Do not set concentrations for int stds, leave blank
15
Method – cont.
 Set “Sampling”: Sample Flush (35 sec), Read Delay (45-60 sec), and Wash (90-120 sec) (If
you have a limited amount of sample, <3 mL, please talk to the Instrument Manager about
optimizing these settings.)
• Define the autosampler location, “A/S Loc.”, and name “Solution ID”
• You may enter a “Wash Override” time (longer than the normal wash time) in the row
of high concentration standards to minimize contamination of following samples
16
Method – cont.
 Set “Report”
• Check “Send to Printer” and use template “Quant summary new.rop”.
• Check “Send to File” and choose a template. Name and save your report
to the “ReportOutput” folder. (May use the same report filename for multiple
analyses.) Check all options under “Report Format” and choose “Append”
under “File Write Option”.
• Open “File  Save as” and save
your method to
C:\Elandata\Method\your folder\method
name
17
Sample List
 Click on “Sample” icon and select “Batch” tab
• Go to “File  New”, or go to “File  Open” and choose your sample file
• Define the “A/S Loc.” (autosampler location ), “Batch ID” (Date), and “Sample ID”.
*It is highly recommended that you rerun the blank before analyzing your samples*
• Select “Measurement Action” by right clicking (Set the first sample as “Run Blank, Standard,
and Sample”. Following samples should use “Run Sample”.)
• Choose “Method” by right clicking and select your method
• Open “File  Save as” and save your sample list to C:\Elandata\Sample\your
folder\sample file name
*Sample Template instructions on page 22*
18
Calibration and Measurement
If you have not yet completed tuning do so before continuing (page 8)
• Immerse sample tubing into wash solution on auto sampler and int std
tubing into the internal standard solution located near the pump, and
open all the caps of sample tubes
• Highlight the list of samples, and click on “Build Run List”
19
Calibration and Measurement (auto sampler) – cont.
 Click on “Analyze Batch” in the new window
• View calibration via “CalibView” and sample reports in the PDF file
• Save result in PDF in C:\userdata\your folder\file name
*See pages 23-24 for instructions in data reprocessing and retrieving data in excel format.*
20
Shut-down
 Wash the system: immerse the sample and int std tubing in acid
solution for 5 min and then in water for 2 min
• Take the tubing out of solution, put them in the empty tube, and wait
until spray chamber is dry (no more bubbles leave the bottom of the spray
chamber)
• Click on “Instrument”, and turn off plasma by
clicking on “stop”
• Unclamp and loosen the sample, int std,
and drain tubing
21
Sample Template
•
•
Automatically generate Sample ID and A/S Loc. by clicking “Sample Template”
“Sample ID”  Samples must be numbered and may have a prefix and/or suffix of your choice,
indicate an increment for the sample numbers to increase by (Example: No Prefix, Number 3,
Increment 1, Suffix a  3a, 4a, 5a,…)
•
•
•
“Auto Sampler Position”  Indicate the number of the A/S Loc. that the samples start at and the
increment
“Range”  indicate the row in the spreadsheet that the samples start at and where they should
end (start row + number of samples - 1)
Click “Generate”
22
Data Reprocessing
•
Reprocess data to get actual standard concentrations or 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)
•
•
If you have made no changes to your method and simply want to get your actual standard
concentrations go to your dataset  select the rows containing your blank and standards  click
“Reprocess” (sample concentrations should be the same so you don’t need to reprocess them)
If you have altered your method and need both sample and standard information reprocessed go
to your dataset  select the rows containing your blank and standards only  click “Reprocess”
 repeat  if the reported standard concentrations are the same both times close the PDF file
 select the rows containing your blank, standards, and samples  click “Reprocess” (if the
reported standard concentrations are not the same try reprocessing the standards one more time, if they don’t match your
second reprocessing get the instrument manager)
23
Data Reprocessing - Excel
•
•
•
•
To get a summary of your sample concentrations in excel format click on “Summary Report”  choose to
organize your summary by “Analyte” or “Sample”  choose “Cross Tab” and indicate the number of significant
figures you want  uncheck “Printer” and check “File”  click “Browse” and save in
C:\Elandata\ReportOutput\your folder\file name  click “OK”
In your dataset highlight the rows for your blank, standards, and samples and click “Reprocess”
Open MS Excel and open your file (C:\Elandata\ReportOutput\your folder\file name) by choosing to view “All File
Types”  use the import wizard to organize the data (data is comma delimited)  save as an Excel or CSV file
You may also get detailed sample information (intensities and RSDs) in Excel by going to Excel and opening the
file listed under the “Report” tab of your method (this data is not as easy to organize as the summary data)
24
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-MS 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.
25
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 supernatant,
and then filter the supernatant to be used for analysis using 0.45 µm, or smaller, pore size filters.
26