Table 1. Typical regulated elements and allowable limits for drinking water in the
United Kingdom (NS30), European Union (EU) and United States of America (USA)
Element
Silver (Ag)
Aluminum (Al)
Arsenic (As)
Boron (B)
Barium (Ba)
Berilium (Be)
Calcium (Ca)
Cadmium (Cd)
Chromium (Cr)
Copper (Cu)
Iron (Fe)
Mercury (Hg)
Potassium (K)
Magnesium (Mg)
Manganese (Mn)
Molybdenum (Mo)
Sodium (Na)
Nickel (Ni)
Phosphorous (P)
Lead (Pb)
Antimony (Sb)
Selenium (Se)
Thallium (Tl)
Uranium (U)
Vanadium (V)
Zinc (Zn)
NS30
(µg/L)
EU
(µg/L)
USA
(µg/L)
10
200
50
2,000
1,000
–
250,000
5
50
3,000
200
1
12,000
50,000
50
–
150,000
50
2,200
50
10
10
–
–
–
5,000
–
200
10
1,000
–
–
–
5
50
1,000
200
1
–
–
50
–
200,000
20
–
10
5
10
–
–
50
–
100
200
10
–
2,000
4
–
5
100
1,000
300
2
–
–
50
–
–
–
–
15
6
50
2
30
–
5,000
w w w. p e r k i n e l m e r. c o m
N O T E
Drinking-water regulations have
been established in most industrialized nations. Although the
list of elements for each country
is typically very similar, the
regulatory limits can vary, as
shown in Table 1. ICP-MS has
become a popular technique for
the analysis of drinking water
because of its very low detection
limits and short analysis time.
Performing an analysis for as
many as 30 elements by ICP-MS
generally takes less than 5 minutes
per sample, compared to several
hours per sample using other
techniques with similar detection
capabilities, such as graphite
furnace atomic absorption.
A P P L I C A T I O N
Introduction
I C P M A S S S P E C T R O M E T RY
Interference Removal and
Analysis of Environmental Waters
Using the ELAN DRC-e ICP-MS
Authors
Kenneth R. Neubauer, Ph.D.
Ruth E. Wolf, Ph.D.
PerkinElmer Life and
Analytical Sciences
710 Bridgeport Avenue
Shelton, CT 06484 USA
However, depending on the matrix
content and sample-preparation
strategies, some elements (such as
arsenic, selenium, chromium, iron
and nickel) may suffer from polyatomic interferences in ICP-MS.
These interferences may be even
more troublesome in other environmental water samples, such as bottled
water or wastewater because of the
higher matrix content. These interferences can be overcome in most
cases by applying elemental correction equations or monitoring an
alternative isotope. Unfortunately,
for monoisotopic elements such as
arsenic, an alternative isotope is
not available. Additionally, some
matrices have such high levels of
interferences that the use of interference corrections becomes difficult.
Table 2 lists some commonly
occurring interferences in ICP-MS
that may affect the analysis of
environmental samples such as
drinking water.
An alternative approach to applying
interference correction equations is
to remove the interferences prior to
analysis. This can be accomplished
with the ELAN® DRC-e ICP-MS
(PerkinElmer SCIEX™, Concord, ON,
Canada). The ELAN DRC-e uses
patented Dynamic Reaction Cell™
(DRC™) technology to chemically
remove the interferences from the
ion beam before they enter the
analyzer quadrupole. The DRC
consists of a quadrupole mass filter
in an enclosed cell located between
the ion optics and the analyzer
quadrupole of an ICP-MS. The
enclosed cell can be pressurized
with a reaction gas that chemically
reacts with the interfering species
to remove them from the ion beam.
In addition, the active quadrupole
inside the DRC provides the ability
to establish a mass bandpass
2
window, with both a high-mass and
low-mass cutoff, inside the cell.
Ions that are not stable within this
mass bandpass window are ejected
from the cell before they can enter
the analyzer quadrupole. The bandpass window can be automatically
changed with the analyte mass via
Dynamic Bandpass Tuning (DBT)
to carefully control the chemistry
occurring inside the cell. This
unique feature provides control of
the reaction chemistry to eliminate
the possibility of new interferences
forming within the reaction cell. In
addition, Axial Field Technology
(AFT) provides optimal performance
in any matrix. With the ELAN DRC-e,
interferences are eliminated by this
combination of chemical resolution
and DBT inside the Dynamic Reaction
Cell, minimizing the need to use
correction equations.
The data presented in this paper
demonstrate the capabilities of the
ELAN DRC-e for running all of the
elements in U.S. Environmental
Protection Agency (EPA) Method
200.8, the standard method used
in the U.S.A. for the analysis of
drinking waters and wastewaters
Table 2. Common interferences in ICP-MS
Interfering Species
Affected Elements
40Ar35Cl+, 40Ar37Cl+, 40Ca35Cl+, 40Ca37Cl+
75As+, 77Se+
79BrH+, 81BrH+
80Se+, 82Se+
35Cl16O+, 37Cl16O+
51V+, 53Cr+
40Ar12C+
52Cr+
40Ar14N+
54Fe+
40Ar16O+, 40Ca16O+
56Fe+
40Ar16OH+, 40Ca16OH+
57Fe+
42Ca16O+, 44Ca16O+
58Ni+, 60Ni+
40Ar23Na+
63Cu+
Table 3. ELAN DRC-e instrumental parameters
Parameter
RF Power
Nebulizer Gas Flow
Sample Introduction Rate
Nebulizer
Spray Chamber
Reaction Gas
DRC Pressurization Time
DRC Gas Flow Change Time
DRC Vent Time
Detector Mode
Lens
Sampler/Skimmer Cones
Dwell Time
Points per Peak
Sweeps per Reading
Readings per Replicate
Replicates
Value
1300 W
~0.85-0.95 L/min (set for < 3% oxides)
1 mL/min
Cross-flow Gem-tip
Ryton® Scott-type Double-pass
Methane (99.999%)
30 sec
15 sec
30 sec
Dual
Scanning
Nickel
50 ms
1
20
1
3
by ICP-MS. Although the data was
based on Method 200.8, it can also
be used to demonstrate performance
improvements for these elements
under the methods required by
other countries.
Although the majority of elements
specified in U.S. EPA Method 200.8
are determined without much
difficulty by conventional ICP-MS,
a few may suffer from interferencerelated problems in certain matrices.
In these cases, an alternative samplepretreatment step or alternate analytical technique may be needed to
confirm the results, which increases
the time and cost of the analysis.
It would be highly advantageous to
Table 4a. Isotopes monitored and applicable parameters in standard mode
†
Analyte
Isotope
RPq†
Al
Sb
As
Ba
Be
Cd
Cr
Co
Cu
Fe
Pb
Mn
Mo
Ni
Se
Ag
Tl
Th
U
V
Zn
Ca
Mg
Na
K
27
121, 123
75
135, 137
9
111, 114
52
59
63, 65
54, 57
208
55
98
60
82
107
205
232
238
51
66
43, 44
24
23
39
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.65
0.65
0.65
0.65
Correction Equations
Experimental
-3.127 * [ArCl77 - (0.815 * Se82)]
+1 * Pb206 + 1 * Pb207
-1.008696 * Kr83
RPq is the Dynamic Bandpass Tuning parameter
Table 4b. Isotopes monitored and applicable parameters in DRC mode
†
Element
m/z
CH4 Flow
(mL/min)
RPq†
Cr
Ni
As
Se
Se
52
60
75
78
80
0.60
0.60
0.15
0.60
0.60
0.70
0.70
0.70
0.70
0.70
RPq is the Dynamic Bandpass Tuning parameter
run all the elements in a single
multielemental analysis in order
to improve sample throughput and
decrease the cost of analysis. The
data in this paper show that by
using the ELAN DRC-e, all of the
elements in a typical drinking-water,
bottled-water or wastewater sample
analyzed using U.S. EPA Method
200.8 can be run in a single analysis
using a single reaction gas – even
those with problematic interferences.
All work discussed here was
performed on an ELAN DRC-e
in a normal laboratory setting
(i.e., non-cleanroom conditions).
The guidelines outlined in the U.S.
EPA Method 200.8 turnkey application note were followed.1 The
objective of this work was to
develop a single, robust analytical
method using one reaction gas for
the analysis of water samples in
order to maximize sample throughput, overall laboratory productivity
and ease-of-use. The instrument
conditions used for this method
are displayed in Table 3. While the
stated goal has been achieved, it
should be noted that, if necessary,
superior performance for some
elements determined in DRC mode
may be achieved using individually
optimized conditions for each
element or a different reaction gas.
Tables 4a and 4b show the elements
measured, the mode used, and the
appropriate reaction-cell conditions.
DRC-mode analysis indicates that
the DRC was pressurized with a
reaction gas and Dynamic Bandpass
Tuning applied. For all the DRCmode analyses, 99.999% methane
(Matheson Gas Products, East
Rutherford, NJ, USA) was used as
the reaction gas. Standard mode
w w w. p e r k i n e l m e r. c o m
3
indicates that the DRC cell was not
pressurized (i.e., the reaction gas was
turned off) and is approximately
equivalent to running the elements
on an ELAN 9000 instrument. All
of the elements analyzed in DRC
mode were also analyzed in standard
mode for comparison purposes. By
analyzing samples this way, each
sample is run one time with one
method, and both DRC- and standardmode analyses are accomplished
with one optimization file. This
scheme eliminates the need to
analyze each sample more than
once, to use two methods or to use
two optimization files.
For various elements, multiple
isotopes were monitored for comparison purposes. Table 4a also
shows any interference corrections
(if used) for standard-mode analysis.
Calibration standards were made in
1% nitric acid at the levels indicated
in Table 5 and run as an external
calibration curve. The calibration
blank was a 1% nitric acid solution,
and blank subtraction was used. An
internal standard mixture was added
to the blank, the standards and each
sample to yield a final concentration
of 20 µg/L 6Li, 45Sc, 71Ga, 103Rh, 115In,
165
Ho and 193Ir.
A wastewater reference material
(High Purity Standards, Charleston,
SC, USA) and a municipal wastewater were digested using U.S. EPA
Method 200.2. Spikes were added
prior to digestion.
Results
Interference Reduction
The major elements in environmental
water that suffer from interferences
include Cr, Ni, As and Se; their
associated interferences are ArC+,
CaO+, ArCl+ and Ar2+, respectively.
These interferences originate from
4
Table 5. Calibration standard concentrations
Analytes
Standard 1
(µg/L)
Standard 2
(µg/L)
Standard 3
(µg/L)
Al, Sb, As, Ba, Be, Cd,
Cr, Co, Pb, Mn, Mo, Ni,
Se, Ag, Tl, Th, U, V, Zn
10
20
100
Na, Mg, K, Ca, Fe
200
1,000
10,000
Table 6a. Instrument detection limits (IDLs) and Matrix-IDLs in standard mode
Analyte
m/z
Be
Al
V
Cr
Mn
Co
Ni
Cu
Zn
As
Se
Mo
Ag
Cd
Sb
Ba
Tl
Pb
Th
U
Na
Mg
K
Ca
Fe
9
27
51
52
55
59
60
63
66
75
82
98
107
114
121
135
205
208
232
238
23
24
39
43
54
IDL
(µg/L)
0.005
0.010
0.005
0.013
0.002
0.001
0.004
0.006
0.010
0.026
0.070
0.002
0.003
0.002
0.002
0.006
0.001
0.001
0.002
< 0.001
0.106
0.048
0.789
1.104
0.593
Matrix-IDL
(µg/L)
200Matrix-IDL
(µg/L)
0.004
0.117
1.22
0.952
0.023
0.009
0.358
0.006
0.070
0.077
0.122
0.010
0.008
0.013
0.015
0.019
< 0.001
0.010
0.003
0.001
0.383
0.139
3.07
N.A.
0.606
–
–
–
–
–
–
0.577
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
N.A. = Not Applicable (Ca in matrix)
Table 6b. Instrument detection limits (IDLs) and Matrix-IDLs in DRC mode
Analyte
m/z
IDL
(µg/L)
Matrix-IDL
(µg/L)
200Matrix-IDL
(µg/L)
Cr
Ni
As
Se
52
60
75
80
0.003
0.004
0.006
0.006
0.150
0.111
0.176
0.010
–
0.071
–
–
matrix and/or plasma species. To
reduce these interferences, methane
was used as the reaction gas.
Although Fe can suffer from ArN+,
ArO+, CaO+, ArOH+ and CaOH+
interferences at low levels, it is
usually present at elevated levels
in North American drinking waters,
and therefore can be determined in
standard mode.1
The ELAN software performs an
optimization routine that allows the
correct gas flow to be chosen. This
optimization is performed once, and
the optimum gas-flow settings are
then stored in the analytical method
for use in routine analysis.
An example showing the reactioncell gas eliminating an interference
appears in Figure 1. In this example, methane is the reaction gas and
the matrix consists of 50 mg/L Ca,
0.5% HCl and 0.2% MeOH. In this
figure, the red line represents the
signal due to the matrix, and the
blue line is the signal resulting from
the matrix + 1 µg/L Ni plotted as
a function of methane flow. The
difference between these lines
represents the signal due to 1 µg/L
Ni. From this plot, it is evident that
methane removes the CaO+ interference on Ni. The appropriate cell
gas flows for the other elements
were determined in a similar
manner. The final methane flow
and bandpass parameters used for
the analysis are shown in Table 4b.
Method Validation
Both instrumental detection limits
(IDLs) and matrix instrument
detection limits (Matrix-IDLs) were
determined (Table 6). As defined by
the U.S. EPA, detection limits were
calculated by measuring a sample
eight times, using three replicates
per measurement. The standard
deviation of these eight measurements was then multiplied by three
Figure 1. Cell gas optimization plot of Ni in a calcium matrix. The red line (squares) represents
the signal at m/z 60 at various CH4 flows from a matrix consisting of 50 mg/L Ca + 0.5% HCl +
0.2% methanol. The blue line (diamonds) is for the same solution, but spiked with 1 µg/L Ni.
Table 7. Analysis of a drinking-water certified reference material (Trace Metals in
Drinking Water, High Purity Standards)
Standard Mode (unless indicated)
Analyte
m/z
Certified
Value
(µg/L)
Experimental
Value
(µg/L)
Recovery
(%)
Be
Al
V
Cr
Cr DRC-e
Mn
Co
Ni
Ni DRC-e
Cu
Zn
As
As DRC-e
Se
Se DRC-e
Mo
Ag
Cd
Sb
Ba
Tl
Pb
Th
U
Na
Mg
K
Ca
Fe
9
27
51
52
52
55
59
60
60
63
66
75
75
82
80
98
107
114
121
135
205
208
232
238
23
24
39
43
54
20
120
30
20
20
40
25
60
60
20
70
80
80
10
10
100
2
10
10
50
10
40
–
10
6,000
9,000
2,500
35,000
100
20.2
121
30.8
20.7
19.3
39.5
24.8
60.4
54.8
20.0
63.4
75.5
75.5
9.0
9.6
96.6
1.9
9.7
9.5
49.0
10.1
39.6
0.002
9.8
6,200
9,350
2,130
31,200
114
101
100
101
103
97
99
99
101
91
100
91
94
94
90
96
97
94
97
95
98
101
99
–
98
103
104
85
89
114
to obtain the detection limit for each
element. The instrument detection
limit (IDL) for each element was
determined by measuring a 1%
nitric acid blank; the Matrix-IDLs
were determined in the same manner, except a solution consisting of
50 µg/L Ca, 0.2% methanol and
0.1% HCl was analyzed. This matrix
solution was devised to test the
detection capabilities of the ELAN
DRC-e in a sample matrix containing
the common interfering species of
calcium, chloride and carbon which
can lead to the interferences listed
in Table 2. In addition, since many
natural waters and wastewaters
contain high levels of calcium that
lead to increased levels of CaO+
interference and false positives for
nickel in these types of samples, the
Ni detection limit was also evaluated
in a solution containing 200 mg/L
calcium (Matrix200-IDL). The
advantage of DRC-mode analysis
is evident in the results in Tables
6a and 6b.
As Tables 6a and 6b illustrate, the
detection limits determined in DRC
mode are superior to those determined in standard mode for most
elements and are adequate for the
determination of analytes at normal
levels in drinking-water samples.
Even at high calcium concentrations, the DRC-mode Matrix200-IDL
for nickel is substantially better than
that determined in standard mode
and comparable to the Matrix-IDL
determined in the solution containing calcium, chloride and carbon.
Thus, the use of DRC mode will
result in a more robust determination for nickel using the mass 60
isotope (the most abundant practical
isotope) in various types of calciumcontaining matrices, such as hard
waters and treated wastewaters.
Table 8. Analysis of trace metals in a natural-water certified reference material (NIST 1640)
Standard Mode (unless indicated)
Analyte
m/z
Certified
Value
(µg/L)
Experimental
Value
(µg/L)
Recovery
(%)
Be
Al
V
Cr
Cr DRC-e
Mn
Co
Ni
Ni DRC-e
Cu
Zn
As
As DRC-e
Se
Se DRC-e
Mo
Ag
Cd
Sb
Ba
Tl
Pb
Th
U
Na
Mg
K
Ca
Fe
9
27
51
52
52
55
59
60
60
63
66
75
75
82
80
98
107
114
121
135
205
208
232
238
23
24
39
43
54
34.94
52.0
12.99
38.6
38.6
121.5
20.28
27.4
27.4
85.2
53.2
26.67
26.67
21.96
21.96
46.75
7.62
22.79
13.79
148.0
< 0.1
27.89
–
–
29,350
5,819
994
7,045
34.3
32.8
44.3
11.7
33.0
36.6
111
19.2
25.7
25.9
81.7
53.4
25.8
25.4
22.2
18.8
45.0
7.13
22.7
13.3
138
0.01
27.0
0.03
0.80
28,500
5,600
885
6,450
34.2
94
85
90
85
95
91
95
94
94
96
100
97
95
101
85
96
94
99
97
93
–
97
–
–
97
96
89
92
100
To test the method performance, a
drinking-water standard reference
material, Trace Metals in Drinking
Water (High Purity Standards), was
analyzed. The results are presented
in Table 7. The data in Table 7 show
that the experimental values for the
analytes in Method 200.8 are
generally within 10% of the certified
values for all the elements determined in both standard and DRC
modes. This is considered an acceptable recovery for U.S. EPA Method
200.8, which requires the measured
value of an external quality-control
sample to be within ±10% of the
stated value. The alkali metals are
not listed as analytes in Method
200.8, but are included for informational purposes. The results for
K and Ca are somewhat low,
probably due to the comparatively
low value of the high calibration
standard for these elements as
compared to the levels present in
the sample. Table 8 shows similar
results for a certified natural-water
sample and Table 9 for a wastewater
w w w. p e r k i n e l m e r. c o m
6
material. The Al and V values in the
wastewater sample are higher than
expected. The high Al value is
likely due to contamination during
the digestion step. The high V
measurement may be due to the
presence of another interference,
such as ClO+, arising from the HCl
used in the digestion step.
To evaluate the method on real
samples, drinking-water, bottledwater and wastewater samples were
analyzed. The results for these
samples, as well as recoveries for
a 10 µg/L spike, are presented in
Tables 10, 11 and 12. These results
show that the major matrix species
are present at different levels in the
samples, as evidenced by the
differing Ca, Na, K and Mg concentrations. Nevertheless, spike recoveries are within ±10% for all
elements present in the samples
at concentrations under 50 µg/L.
The wastewater sample spikes were
added prior to digestion, so the
acceptable limits for the spike
recovery are broader at ±20%.
For samples where the unspiked
concentrations are greater than ten
times the spike value, recovery
calculations were not performed.
Table 9. Analysis of a wastewater certified reference material (Trace Metals in
Wastewater E, High Purity Standards)
Standard Mode (unless indicated)
Analyte
m/z
Certified
Value
(µg/L)
Experimental
Value
(µg/L)
Recovery
(%)
Be
Al
V
Cr
Cr DRC-e
Mn
Co
Ni
Ni DRC-e
Cu
Zn
As
As DRC-e
Se
Se DRC-e
Mo
Ag
Cd
Sb
Ba
Tl
Pb
Th
U
Na
Mg
K
Ca
Fe
9
27
51
52
52
55
59
60
60
63
66
75
75
82
80
98
107
114
121
135
205
208
232
238
23
24
39
43
54
5
25
25
25
25
25
25
25
25
25
25
5
5
5
5
25
5
25
5
25
5
25
–
–
–
–
–
–
25
5.21
32.9
34.1
23.7
25.1
24.9
22.7
23.1
24.3
23.6
25.9
3.68
5.24
4.03
3.60
22.9
4.87
23.3
5.00
24.2
4.37
23.4
–
–
–
–
–
–
26.5
104
132
137
95
100
100
91
92
97
95
104
74
105
81
72
92
97
94
100
97
97
94
–
–
–
–
–
–
106
In the public-water sample (Table
10), a difference of about 8 µg/L
is observed in the nickel values
measured under standard and DRC
conditions. The higher value results
from standard-mode analysis and
indicates an interference contributing to the apparent 60Ni signal, most
likely CaO+. Applying DRC-mode
conditions eliminates the interference and leads to a much better
spike recovery (98%). The same
effect is also evident for Ni in the
bottled-water sample (Table 11).
Figure 2a. Stability analysis of low-level elements (0.1-0.7 µg/L) in tap water over 9.5 hours. In the
legend, s= standard mode, D=DRC mode.
w w w. p e r k i n e l m e r. c o m
7
These results indicate that the DRC
mode removes interferences, thereby
allowing lower concentrations to
be measured.
The stability of the method was
evaluated by analyzing a tap-water
sample for 9.5 hours against an
external calibration curve. Figures
2a and 2b show stability plots of
several DRC- and standard-mode
elements; Figure 2a shows data for
low-level analytes (concentrations
below 0.7 µg/L), and Figure 2b
shows data for high-level elements
(greater than 1 mg/L). These plots
demonstrate the stability of the
method while switching between
standard- and DRC-mode analysis
by showing how stable the measurements are, both at very low and very
high levels.
Interferences can greatly affect
an analysis, but the ELAN DRC-e
eliminates them, leading to more
stable analyses. This is demonstrated
in Figure 3, for the determination of
52
Cr in a tap-water sample over 9.5
hours. In standard mode, the 52Cr
signal is initially approximately
0.5 µg/L but continuously decreases
with time to slightly less than
0.1 µg/L. This indicates that an
interference must be present on 52Cr
signal in standard mode, leading to
the instability of the signal, as well
as the high baseline values. The most
probable explanation for the decline
in this standard-mode mass 52 signal
is the decreasing carbon content of
the water, resulting from CO2 outgassing to establish an equilibrium.2
As the carbon-dioxide content of
the water decreases with time, the
amount of carbon available in the
sample matrix to form ArC+ in the
plasma decreases; hence, the decrease
in the background signal at mass 52
8
Table 10. Analysis of a Connecticut public water supply with a 10 µg/L spike
Standard Mode (unless indicated)
Analyte
m/z
Sample
(µg/L)
Sample + Spike
(µg/L)
Spike Recovery
(%)
Be
Al
V
Cr
Cr DRC-e
Mn
Co
Ni
Ni DRC-e
Cu
Zn
As
As DRC-e
Se
Se DRC-e
Mo
Ag
Cd
Sb
Ba
Tl
Pb
Th
U
Na
Mg
K
Ca
Fe
9
27
51
52
52
55
59
60
60
63
66
75
75
82
80
98
107
114
121
135
205
208
232
238
23
24
39
43
54
0.007
21.0
< DL
< DL
< DL
1.9
0.05
51.2
43.1
651
294
0.4
0.4
0.5
0.2
0.2
0.02
< DL
0.1
8.2
0.008
2.2
0.008
0.003
14,393
2,818
1,984
14,977
22.0
10.6
31.0
10.2
10.1
10.0
11.6
10.3
60.0
52.9
*
*
11.5
11.4
12.7
10.6
10.2
10.1
10.5
10.7
18.5
9.2
12.1
8.8
8.7
*
*
*
*
*
106
100
96
96
99
97
103
88
98
*
*
111
110
120
103
100
101
105
106
103
92
99
88
87
*
*
*
*
*
*Spike was too low relative to the native concentration
Figure 2b. Stability analysis of high-level elements (2-20 mg/L) in tap water over 9.5 hours. These
elements were determined in standard mode.
from ArC+. Since this interference is
eliminated using DRC mode, the
background for the signal is substantially lower at about 0.1 µg/L
and very stable (with the exception
of a small plateau around the 5-hour
mark due to Cr contamination in one
of the autosampler vials). It is also
interesting to note that after approximately 7.5 hours, the standard-mode
background signal level at mass 52
is at the same level as in DRC mode.
Presumably, this indicates that
equilibrium has been established
and carbon dioxide is no longer
being liberated from the sample.
Conclusion
The results of this study indicate
that the ELAN DRC-e can be used
to analyze environmental-water
samples using both standard-mode
and DRC-mode analysis in a single
analytical run using a single reaction
gas. The total time of analysis per
sample, including sample uptake,
read delay and rinse times, was just
under 6 minutes per sample for a
total of 45 isotopes, although fewer
isotopes would be used in a typical
analysis (multiple isotopes were
used for method-development and
validation purposes). The data
shown were analyzed following
the guidelines in U.S. EPA Method
200.8 for drinking-water and
wastewater analysis in the United
States. Following this method, the
IDLs, Matrix-IDLs and recoveries
for a certified reference material
are reported.
The use of a reaction gas in the
ELAN DRC-e provides the ability
to measure lower levels of certain
elements in samples due to the
elimination of matrix- and plasmabased polyatomic interferences. The
data also show that the stability of
the system is maintained, even while
Table 11. Analysis of a bottled water and 10 µg/L spike
Standard Mode (unless indicated)
Analyte
m/z
Sample
(µg/L)
Sample + Spike
(µg/L)
Spike Recovery
(%)
Be
Al
V
Cr
Cr DRC-e
Mn
Co
Ni
Ni DRC-e
Cu
Zn
As
As DRC-e
Se
Se DRC-e
Mo
Ag
Cd
Sb
Ba
Tl
Pb
Th
U
Na
Mg
K
Ca
Fe
9
27
51
52
52
55
59
60
60
63
66
75
75
82
80
98
107
114
121
135
205
208
232
238
23
24
39
43
54
< DL
0.6
0.1
< DL
0.2
0.1
< DL
1.0
0.3
< DL
< DL
0.3
0.4
0.1
0.1
0.5
0.008
< DL
0.8
107
0.007
< DL
0.008
1.7
6,300
26,232
974
60,120
90.5
9.3
10.2
9.4
10.1
10.8
9.2
10
10.9
10.5
9.9
9.0
10.7
10.3
10.2
9.6
10.5
9.5
9.8
10.9
*
10.5
10.0
9.8
11.6
*
*
*
*
*
93
96
93
93
106
91
100
99
102
99
90
104
99
101
95
100
95
98
101
*
105
100
98
99
*
*
*
*
*
*Spike was too low relative to native concentration
Figure 3. Chromium signals in standard (blue squares) and DRC (red triangles) modes for a 9.5
hour analysis of tap water. The lower, steadier signal in DRC mode indicates removal of the ArC+
interference. The decreasing Cr signal in standard mode results from dissolved CO2 outgassing
over time, resulting in a decreasing carbon (ArC+) background.
w w w. p e r k i n e l m e r. c o m
9
switching between DRC and standard
modes of analysis within a method.
These results demonstrate that the
ELAN DRC-e ICP-MS can be used
for effective multielemental analysis
of drinking water, bottled water and
a typical municipal wastewater,
even those with significant calcium
content. It is superior to conventional ICP-MS for several key
elements because common polyatomic interferences are removed.
References:
1. U.S. EPA Method 200.8 for the
Analysis of Drinking Waters and
Wastewaters, Application Note
D-6527, Ruth E. Wolf, Eric
Denoyer and Zoe Grosser,
PerkinElmer Instruments, 2001.
2. Environmental Chemistry, 5th
Edition, Stanley E. Manahan,
Lewis Publishers, 1991, pages
40-42, 156.
Table 12. Analysis of a municipal wastewater and 10 µg/L pre-digestion spike
Standard Mode (unless indicated)
Analyte
m/z
Sample
(µg/L)
Sample + Spike
(µg/L)
Spike Recovery
(%)
Be
Al
V
Cr
Cr DRC-e
Mn
Co
Ni
Ni DRC-e
Cu
Zn
As
As DRC-e
Se
Se DRC-e
Mo
Ag
Cd
Sb
Ba
Tl
Pb
Th
U
Na
Mg
K
Ca
Fe
9
27
51
52
52
55
59
60
60
63
66
75
75
82
80
98
107
114
121
135
205
208
232
238
23
24
39
43
54
0.02
698
10.3
4.13
5.35
131
0.493
10.0
9.6
51.2
53.8
< DL
6.06
1.19
1.48
3.14
2.89
0.172
0.403
97.1
0.05
2.96
0.01
0.24
–
9,470
6,000
37,000
480
9.51
*
20.8
12.4
15.3
*
9.49
17.9
18.0
60.9
64.0
8.8
15.9
9.25
9.56
12.6
11.3
9.04
9.73
108
8.14
11.5
–
8.31
*
*
*
*
*
95
*
105
83
100
*
90
79
84
97
102
88
98
81
81
95
84
89
93
109
81
85
–
81
*
*
*
*
*
*Spike was too low relative to native concentration
PerkinElmer Life and
Analytical Sciences
710 Bridgeport Avenue
Shelton, CT 06484-4794 USA
Phone: (800) 762-4000 or
(+1) 203-925-4602
www.perkinelmer.com
For a complete listing of our global offices, visit www.perkinelmer.com/lasoffices
©2004 PerkinElmer, Inc. All rights reserved. The PerkinElmer logo and design are registered trademarks of PerkinElmer, Inc. Dynamic Reaction Cell and DRC are trademarks of PerkinElmer,
Inc. or its subsidiaries, in the United States and other countries. ELAN is a registered trademark of MDS Sciex, a division of MDS, Inc. All other trademarks not owned by PerkinElmer, Inc.
or its subsidiaries that are depicted herein are the property of their respective owners. PerkinElmer reserves the right to change this document at any time without notice and disclaims
liability for editorial, pictorial or typographical errors.
006869_01
ELEC070400