Class Data:
Cross Country Field – Core 3 Profile
δ 13C (‰ vs.VPDB)
Gr. 3-5A
Gr. 3-15
Gr. 3-25
Gr. 3-45
Gr. 3-55
Gr. 3-61
Gr. 3-70
Gr. 3-85
Gr. 3-92
Gr. 3-100
Gr. 3-110
Gr. 3-120
Gr. 3-135
Gr. 3-145
Gr. 3-159
Depth δ13C
(cm) (‰)
5 -24.70
15 -24.14
25 -24.05
45 -23.71
55 -23.60
61 -23.47
70 -23.43
85 -24.28
92 -23.98
100 -24.30
110 -24.31
120 -24.79
135 -24.54
145 -24.53
159 -24.85
mean -24.18
st dev 0.47
Carbon Nitrogen
(%)
(%)
1.62% 0.17%
1.02% 0.12%
0.71% 0.09%
0.38% 0.05%
0.32% 0.05%
0.37% 0.05%
0.39% 0.06%
0.34% 0.05%
0.22% 0.03%
0.23% 0.04%
0.14% 0.03%
0.10% 0.03%
0.11% 0.03%
0.11% 0.03%
0.11% 0.03%
δ13C Depth:
(‰)
(cm)
-24.70
-5
-24.14
-15
-24.05
-25
-23.71
-45
-23.60
-55
-23.47
-61
-23.43
-70
-24.28
-85
-23.98
-92
-24.30
-100
-24.31
-110
-24.79
-120
-24.54
-135
-24.53
-145
-24.85
-159
-25.0
0
-24.5
-24.0
-23.5
-23.0
-20
-40
-60
Depth (cm)
ID
-80
-100
-120
-140
-160
-180
?
Inductively Coupled Plasma Optical Emission Spectrometer (ICP-OES)
ICP-OES has been widely used since the 1970's.
Instrument Description and
Theory
ICP technology was built upon the
same principles used in atomic
emission spectrometry. Samples
are decomposed to neutral
elements in a high temperature
argon plasma and analyzed based
on their mass to charge ratios. An
ICP-MS can be thought of as four
main processes, including sample
introduction and aerosol
generation, ionization by an argon
plasma source, mass
discrimination, and the detection
system. The schematic below
illustrates this sequence of
processes.
Plasma is the phase of matter with its electrons stripped. In argon
plasma, argon ions and electrons act as the conducting species. Three
power sources are dc-electric, radio and microwave frequency
generators. The most advantageous is the radio or inductively coupled
plasma (ICP) because of sensitivity and minimal interference. DC
plasma source (DCP) are also advantageous and is also simple and less
expensive.
Inductive Coupled Plasma consist of three concentric quartz tubes in
which streams of argon flow. Ionization of the argon is initiated by a
spark from a Tesla coil.
The geometries of CP source, in radial geometry or axial geometry
Inductively coupled plasma mass
spectroscopy (ICP-MS) was
developed in the late 1980's to
combine the easy sample
introduction and quick analysis of
ICP technology with the accurate
and low detection limits of a mass
spectrometer.
Figure 3. Schematic of quadrupole mass filter.
(Figure reproduced with permission from PerkinElmer,
Inc.)
analysis
Figure 2. The interface region of an ICP-MS.
(Figure reproduced with permission from
PerkinElmer, Inc.)
sample introduction
Figure 1. The ICP Torch showing the fate of the sample.
(Figure reproduced with permission from PerkinElmer, Inc.)
The resulting instrument is capable
of trace multielement analysis,
often at the part per trillion level.
ICP-MS has been used widely over
the years, finding applications in a
number of different fields including
drinking water, wastewater, natural
water systems/hydrogeology,
geology and soil science,
mining/metallurgy, food sciences,
and medicine.
An ICP-MS combines a high-temperature
ICP (Inductively Coupled Plasma) source
with a mass spectrometer.
Figure 1. The ICP Torch showing the fate of the sample.
(Figure reproduced with permission from PerkinElmer, Inc.)
The most important things to remember about the argon ICP plasma are:
•The argon discharge, with a temperature of around 6000-10000°K, is an excellent ion source.
•The ions formed by the ICP discharge are typically positive ions, M+ or M+², therefore, elements
that prefer to form negative ions, such as Cl, I, F, etc., are very difficult to determine via ICP-MS.
•The detection capabilities of the technique can vary with the sample introduction technique
used, as different techniques will allow differing amounts of sample to reach the ICP plasma.
•Detection capabilities will vary with the sample matrix, which may affect the degree of ionization
that will occur in the plasma or allow the formation of species that may interfere with the analyte
determination.
What can be analyzed?
•Water samples are typically analyzed without sample preparation if they have
been filtered and acidified during collection.
•Sediment, soil and rock samples for total elemental analysis are digested
using a 4-acid digestion procedure in order to dissolve most silicate minerals. This
digestion is carried out in open vessels on a hot-plate, so if volatile elements are
of interest, another digestion procedure such as microwave digestion should be
used.
•Geological samples for rare-earth-element (REE) analysis are typically
prepared using a sodium peroxide sinter method. In this method the ground
sample is mixed with sodium peroxide in a carbon crucible and placed in a muffle
furnace. The resulting sinter is leached with water and acidified with nitric acid
before analysis.
•Biological and organic samples are generally digested using a closed-vessel
microwave digestion procedure that is appropriate to the matrix of the sample.
This is also the best method for digesting organic samples, including crude oils.
•Speciation Analysis is performed on a variety of sample types using High
Performance Liquid Chromatography (HPLC) to separate different chemical forms
of an element followed by ICP-MS detection. Sample collection, storage, and
pretreatment steps are highly specialized.
Photographs of argon plasma
in operation & ICP torch body.
Cyclonic nebulizer in
front of torch body.
Schematic of ICP-MS main processes.
torch
detector
nebulizer
http://www.seaes.manchester.ac.uk/research/facilities/agu/equipment/ICP_MS/moreinfo/
Table 1. Recommended wavelengths
and estimated instrumental
detection limits
• The wavelengths listed are
recommended because of
their sensitivity and overall
acceptance.
• Other wavelengths may be
substituted if they can
provide the needed sensitivity
and are treated with the same
corrective techniques for
spectral interference.
Element
Aluminum
Antimony
Arsenic
Barium
Beryllium
Boron
Cadmium
Calcium
Chromium
Cobalt
Copper
Iron
Lead
Magnesium
Manganese
Molybdenum
Nickel
Potassium
Selenium
Silicon
Silver
Sodium
Thallium
Vanadium
Zinc
Estimated
Wavelength Detection
(nm)
Limit (µg/L)
308.215
45
206.833
32
193.696
53
455.403
2
313.042
0.3
249.773
5
226.502
4
317.933
10
267.716
7
228.616
7
324.754
6
259.940
7
220.353
42
279.079
30
257.610
2
202.030
8
231.604
15
766.491
variable
196.026
75
288.158
58
328.068
7
588.995
29
190.864
40
292.402
8
213.856
2
Inductively Coupled Plasma - (ICP)
Strengths
• Up to 70 elements can be determined simultaneously in a single analysis.
• The useful working range is over several orders of magnitude.
• Instrumentation is suitable to automation.
Limitations
• The emission spectra are complex and inter-element interferences are
possible if the wavelength of the element of interest is very close
to that of another element.
• During Mass Spectrometry, the common matrix elements and other
molecular species can interfere with the measurement of some
elements. Doubly charged or molecular ionic species can create
difficulties in quantifications.
• The sample to be analyzed must be digested prior to analysis in order to
dissolve the element(s) of interest.
Graphite Furnace
Atomic Absorption Spec.
(GFAA)
Graphite
Furnace
2400 oC