Analysis of environmental water samples by ICP-MS - Hacettepe ...

Analysis of environmental water
samples by ICP-MS
ICP-MS-4
July1995
Michael Plantz
Varian Optical Spectroscopy Instruments
Wood Dale IL 60191 USA
Introduction
The part per trillion multielement detection
capabilities of ICP-MS combined with its high sample
throughput are allowing ICP-MS to become the
method of choice for water analysis.
Included in this report are the ICP-MS results
obtained on two different water samples for which
certified reference values are available. These
results are for a United States Envionmental
Protection Agency (US EPA) drinking water
Performance Evaluation Sample and a certified
reference material for river water.
Experimental
Samples
1. USEPA WS-33 Performance Evaluation
Sample, level #1.
2. SLRS-2, Riverine Water Reference Material for
Trace Metals, sampled from the Ottawa River at
Chenaux, Ontario, National Research Council of
Canada.
Internal Standards
45
Sc, 89 Y, 115 In. 159 Tb, 209 Bi at 200 µg/L.
ICP-MS Instrument
Varian UltraMass
Instrument parameters
Plasma flow
Auxillary flow
Nebulizer flow
Sampling depth
Forward power
Sample pump rate
Extraction lens
First lens
Second lens
Third lens
Fourth lens
Photon stop
Entrance plate
Exit plate
15.0 L/min
1.25 L/min
1.10 L/min
9.0 mm
1.2 kW
22 rpm
-600 V
-220 V
-13.4 V
0.0 V
-50 V
-13.2 V
0 V
0 V
1
Segmented Scanning Mode
Reading spacing
0.1 AMU
Points per peak 5
Scans replicate 90
No. of replicates 3
Dwell time
500 µs/channel
Sample delay
30 s
Stabilization delay
5 s
Rinse time
20 s
Analysis time
4 min/sample
(including sample
rinseout)
Results
The results for the USEPA drinking water
Performance Evaluation samples are shown in Table
1, which compares the results acquired with the
UltraMass during a customer training course to the
official results obtained from the nationwide USEPA
Water Supply study. All the UltraMass results fall
within the acceptance ranges of the study, and are
within a few percent or less of the study's 'true value'.
Table 2 displays the results from the analysis of a
certified river water reference material by the
UltraMass. This analysis was performed along with
other environmental samples to illustrate the ability of
the UltraMass ICP-MS system to determine quickly
and accurately the trace metal concentrations in real
environmental samples. This particular sample has
certified values that are defined within a 95%
confidence interval. While no acceptance windows
are provided for this sample, it is clear that the
UltraMass results are extremely accurate. The only
exceptions are the results for calcium and sodium.
The concentrations of these elements in the sample
lay outside the calibrated range of the instrument.
The instrument software automatically provides an
estimate of the concentrations so that the sample
can be diluted for a more accurate analysis for these
elements.
If the UltraMass instrument is equipped with a Varian
SPS-5 Autosampler and Dilutor, then this dilution
would be performed automatically for each sample.

Table 1: Analysis of US EPA Performance
Evaluation Sample: WS-33, vial #1 (results
in µg/L)
Acceptance True UltraMass
Element Limits Value Value
As 33.1 - 45.1 39.5 35.5
Be 7.71- 10.4 9.07 8.3
Cd 39.2 - 58.8 49.0 49.7
Cr 135 - 163 159 156
Cu 1710 - 2090 1900 *1890
Mn 56.7 - 67.7 63.3 64.6
Ni 417 - 563 490 491
Pb 55.1 - 102 76.7 78.4
Se 78.6 - 118 98.3 98.2
Zn 1920 - 2240 2090 *2180
Note: * indicates concentration above top calibration
standard of 200 µg/L
Table 2: Analysis of External Reference Material
Sample: SLRS-2, Riverine Water
Reference Material for Trace Metals
National Research Council of Canada
(results in µg/L)
Certified Concentration
Element Concentration Found
Ca 5700 ±130 4751*
Mg 1510 ±130 1503
Na 1860 ±110 1157*
Al 84.4 ± 3.4 90.7
As 0.77 ± 0.09 0.80
Ba 13.8 ± 0.3 14.9
Cu 2.76 ± 0.17 2.54
Fe 129 ± 7 135.9
Mn 10.1 ± 0.3 9.88
Ni 1.03 ± 0.10 0.90
Sr 27.3 ± 0.4 30.21
Zn 3.33 ± 0.15 3.18
Note: * indicates estimated concentration by use of
MaxiRange;
± indicates 95% confidence interval for
certification value.
Summary
The performance of the UltraMass on these samples
displays its ability to determine quickly and
accurately the concentrations of trace metals in
environmental water samples.
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