SIST EN ISO 17294-1:2007
(Main)Water quality - Application of inductively coupled plasma mass spectrometry (ICP-MS) - Part 1: General guidelines (ISO 17294-1:2004)
Water quality - Application of inductively coupled plasma mass spectrometry (ICP-MS) - Part 1: General guidelines (ISO 17294-1:2004)
This part of ISO 17294 specifies the principles of inductively coupled plasma mass spectrometry (ICP-MS) and provides general directions for the use of this technique for determining elements in water. Generally, the measurement is carried out in water, but gases, vapours or fine particulate matter may be introduced too. This International Standard applies to the use of ICP-MS for water analysis.
Wasserbeschaffenheit - Anwendung der induktiv gekoppelten Plasma Massenspektrometrie (ICP-MS) - Teil 1: Allgemeine Anleitung (ISO 17294-1:2004)
Dieser Teil von ISO 17294 legt die Grundlagen der induktiv gekoppelten Plasma-Massenspektrometrie (ICP MS) fest und gibt allgemeine Hinweise für die Anwendung dieser Technik zur Bestimmung von Elementen in Wasser. Im Allgemeinen wird die Messung in Wasser durchgeführt, kann aber auch auf Gase, Dämpfe oder feine partikuläre Substanzen angewendet werden. Diese Internationale Norm bezieht sich auf die Anwendung der ICP-MS für die Wasseranalytik.
Die eigentliche Durchführung der Elementbestimmung für spezifische Elemente und Matrizes wird jeweils in separaten Internationalen Normen beschrieben. Die individuellen Teile von diesen Internationalen Normen verweisen auf diese Anleitung für die grundlegenden Prinzipien, Verfahren und Gerätekonfigurationen.
Qualité de l'eau - Application de la spectrométrie de masse avec plasma a couplage inductif (ICP-MS) - Partie 1: Lignes directrices générales (ISO 17294-1:2004)
L'ISO 17294-1:2004 spécifie les principes de la spectrométrie de masse avec plasma à couplage inductif (ICP-MS) et présente les directives générales en vue de l'utilisation de cette technique pour la détermination d'éléments dans l'eau. En règle générale, le mesurage est effectué dans l'eau, mais des gaz, des vapeurs ou de fines matières particulaires peuvent également être introduits. L'ISO 17294-1:2004 est axée sur l'application de l'ICP-MS pour l'analyse de l'eau.
La détermination finale des éléments est décrite dans une autre partie de l'ISO 17294 pour chaque série d'éléments et de matrices. Les parties individuelles de l'ISO 17294 renvoient le lecteur aux lignes directrices présentées dans l'ISO 17294-1:2004 en ce qui concerne les principes fondamentaux de la méthode et la configuration de l'instrument.
Kakovost vode - Uporaba induktivno sklopljene plazme z masno selektivnim detektorjem (ICP-MS) - 1. del: Splošne smernice (ISO 17294-1:2004)
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN ISO 17294-1:2007
01-februar-2007
Kakovost vode - Uporaba induktivno sklopljene plazme z masno selektivnim
detektorjem (ICP-MS) - 1. del: Splošne smernice (ISO 17294-1:2004)
Water quality - Application of inductively coupled plasma mass spectrometry (ICP-MS) -
Part 1: General guidelines (ISO 17294-1:2004)
Wasserbeschaffenheit - Anwendung der induktiv gekoppelten Plasma
Massenspektrometrie (ICP-MS) - Teil 1: Allgemeine Anleitung (ISO 17294-1:2004)
Qualité de l'eau - Application de la spectrométrie de masse avec plasma a couplage
inductif (ICP-MS) - Partie 1: Lignes directrices générales (ISO 17294-1:2004)
Ta slovenski standard je istoveten z: EN ISO 17294-1:2006
ICS:
13.060.50
SIST EN ISO 17294-1:2007 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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EUROPEAN STANDARD
EN ISO 17294-1
NORME EUROPÉENNE
EUROPÄISCHE NORM
October 2006
ICS 13.060.50
English Version
Water quality - Application of inductively coupled plasma mass
spectrometry (ICP-MS) - Part 1: General guidelines (ISO 17294-
1:2004)
Qualité de l'eau - Application de la spectrométrie de masse Wasserbeschaffenheit - Anwendung der induktiv
avec plasma à couplage inductif (ICP-MS) - Partie 1: gekoppelten Plasma Massenspektrometrie (ICP-MS) - Teil
Lignes directrices générales (ISO 17294-1:2004) 1: Allgemeine Anleitung (ISO 17294-1:2004)
This European Standard was approved by CEN on 11 September 2006.
CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European
Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national
standards may be obtained on application to the Central Secretariat or to any CEN member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
under the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status as the official
versions.
CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France,
Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania,
Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36 B-1050 Brussels
© 2006 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 17294-1:2006: E
worldwide for CEN national Members.
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EN ISO 17294-1:2006 (E)
Foreword
The text of ISO 17294-1:2004 has been prepared by Technical Committee ISO/TC 147 "Water
quality” of the International Organization for Standardization (ISO) and has been taken over as
EN ISO 17294-1:2006 by Technical Committee CEN/TC 230 "Water analysis", the secretariat of
which is held by DIN.
This European Standard shall be given the status of a national standard, either by publication of
an identical text or by endorsement, at the latest by April 2007, and conflicting national
standards shall be withdrawn at the latest by April 2007.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of
the following countries are bound to implement this European Standard: Austria, Belgium,
Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary,
Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland,
Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
Endorsement notice
The text of ISO 17294-1:2004 has been approved by CEN as EN ISO 17294-1:2006 without any
modifications.
2
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INTERNATIONAL ISO
STANDARD 17294-1
First edition
2004-09-01
Corrected version
2005-03-01
Water quality — Application of
inductively coupled plasma mass
spectrometry (ICP-MS) —
Part 1:
General guidelines
Qualité de l'eau — Application de la spectrométrie de masse avec
plasma à couplage inductif (ICP-MS) —
Partie 1: Lignes directrices générales
Reference number
ISO 17294-1:2004(E)
©
ISO 2004
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ISO 17294-1:2004(E)
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ii © ISO 2004 – All rights reserved
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ISO 17294-1:2004(E)
Contents Page
Foreword. iv
1 Scope. 1
2 Normative references . 1
3 Terms and definitions. 1
4 Principle . 5
5 Apparatus. 5
6 Interferences by concomitant elements .13
7 Adjustment of the apparatus . 19
8 Preparatory steps. 21
9 Procedure. 26
Annex A (informative) Spectral interferences, choice of isotopes and method detection limits for
quadrupole ICP-MS instruments . 29
Bibliography . 33
© ISO 2004 – All rights reserved iii
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ISO 17294-1:2004(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 17294-1 was prepared by Technical Committee ISO/TC 147, Water quality, Subcommittee SC 2, Physical,
chemical and biochemical methods.
ISO 17294 consists of the following parts, under the general title Water quality — Application of inductively
coupled plasma mass spectrometry (ICP-MS):
— Part 1: General guidelines
— Part 2: Determination of 62 elements
This corrected version of ISO 17294-1:2004 incorporates correction of symbols for instrument detection limit
and method detection limit, corrections to Equations (1) and (3), and various minor editorial corrections.
iv © ISO 2004 – All rights reserved
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INTERNATIONAL STANDARD ISO 17294-1:2004(E)
Water quality — Application of inductively coupled plasma
mass spectrometry (ICP-MS) —
Part 1:
General guidelines
1 Scope
This part of ISO 17294 specifies the principles of inductively coupled plasma mass spectrometry (ICP-MS)
and provides general directions for the use of this technique for determining elements in water. Generally, the
measurement is carried out in water, but gases, vapours or fine particulate matter may be introduced too. This
International Standard applies to the use of ICP-MS for water analysis.
The ultimate determination of the elements is described in a separate International Standard for each series of
elements and matrix. The individual parts of this International Standards refer the reader to these guidelines
for the basic principles of the method and for configuration of the instrument.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the reference document
(including any amendments) applies.
ISO Guide 30, Terms and definitions used in connection with reference materials
ISO Guide 32, Calibration in analytical chemistry and use of certified reference materials
ISO Guide 33, Uses of certified reference materials
ISO 3534-1, Statistics — Vocabulary and symbols — Part 1: Probability and general statistical terms
ISO 3696:1987, Water for analytical laboratory use — Specification and test methods
ISO 5725-1, Accuracy (trueness and precision) of measurement methods and results — Part 1: General
principles and definitions
ISO 5725-2, Accuracy (trueness and precision) of measurement methods and results — Part 2: Basic method
for the determination of repeatability and reproducibility of a standard measurement method
ISO 6206, Chemical products for industrial use — Sampling — Vocabulary
ISO 6955, Analytical spectroscopic methods — Flame emission, atomic absorption and fluorescence —
Vocabulary
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 5725-1, ISO 6206, ISO 6955 and
ISO Guide 32 and the following apply.
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ISO 17294-1:2004(E)
3.1
accuracy
closeness of agreement between test result and the accepted reference value
NOTE The term accuracy, when applied to a set of observed values, describes a combination of random error
components and common systematic error components. Accuracy includes precision and trueness.
3.2
analyte
element(s) to be determined
3.3
blank calibration solution
solution prepared in the same way as the calibration solution but leaving out the analyte
3.4
calibration solution
solution used to calibrate the instrument, prepared from (a) stock solution(s) or from a certified standard
3.5
check calibration solution
solution of known composition within the range of the calibration solutions, but prepared independently
3.6
determination
entire process from preparing the test sample solution up to and including measurement and calculation of the
final result
3.7
laboratory sample
sample sent to the laboratory for analysis
3.8
linearity
straight line relationship between the (mean) result of measurement (signal) and the quantity (concentration)
of the component to be determined
3.9
linearity verification solution
solution with a known concentration of the matrix components compared to the calibration solutions, but
having an analyte concentration half that of the (highest) calibration solution
3.10
instrument detection limit
L
DI
smallest concentration that can be detected with a defined statistical probability using a contaminant-free
instrument and a blank calibration solution
3.11
mean result
mean value of n results, calculated as intensity (ratio) or as mass concentration (ρ)
NOTE The mass concentration is expressed in units of milligrams per litre.
3.12
method detection limit
L
DM
smallest analyte concentration that can be detected with a specified analytical method with a defined
statistical probability
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ISO 17294-1:2004(E)
3.13
net intensity
I
signal obtained after correction for (poly)atomic ion interferences using an elemental equation
3.14
net intensity ratio
I
R
net intensity divided by the signal of a reference element
3.15
optimization solution
solution serving for mass calibration and for the optimization of the apparatus conditions
EXAMPLE Adjustment of maximal sensitivity with respect to minimal oxide formation rate and minimal formation of
doubly charged ions.
3.16
precision
closeness of agreement between independent test results obtained under prescribed conditions
NOTE Precision depends only on the distribution of random errors and does not relate to true value or the specified
value.
3.17
“pure chemical”
chemical with the highest available purity and known stoichiometry and for which the content of analyte and
contaminants should be known with an established degree of certainty
3.18
raw intensity
I
raw
obtained uncorrected signal
3.19
reagent blank solution
solution prepared by adding to the solvent the same amounts of reagents as those added to the test sample
solution and with the same final volume
3.20
reproducibility
R
precision under reproducibility conditions
[ISO 3534-1]
3.21
reproducibility conditions
conditions where test results are obtained with the same method on identical test items in different
laboratories with different operators using different equipment
[ISO 3534-1]
3.22
reproducibility standard deviation
standard deviation of test results obtained under reproducibility conditions
[ISO 3534-1]
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ISO 17294-1:2004(E)
3.23
reproducibility limit
value less than or equal to which the absolute difference between two single test results obtained under
reproducibility conditions may be expected to be, with a probability of, generally, 95 %
3.24
repeatability
r
precision under repeatability conditions
[ISO 3534-1]
3.25
repeatability conditions
conditions where independent test results are obtained with the same method on identical test items in the
same laboratory by the same operator using the same equipment within a short interval of time
[ISO 3534-1]
3.26
repeatability standard deviation
standard deviation of test results obtained under repeatability conditions
[ISO 3534-1]
3.27
repeatability limit
value less than or equal to which the absolute difference between two single test results obtained under
repeatability conditions may be expected to be, with a probability of, generally, 95 %
3.28
result
outcome of a measurement
NOTE The result is typically calculated as mass concentration (ρ), expressed in milligrams per litre.
3.29
sensitivity
S
ratio of the variation of the magnitude of the signal (dI) to the corresponding variation in the concentration of
the analyte (dC) expressed by the equation:
dI
S =
dC
3.30
stock solution
solution with accurately known analyte concentration(s), prepared from “pure chemicals”.
NOTE Stock solutions are reference materials within the meaning of ISO Guide 30.
3.31
test sample
sample prepared from the laboratory sample, for example by grinding or homogenizing
3.32
test sample solution
solution prepared with the fraction (test portion) of the test sample according to the appropriate specifications,
such that it can be used for the envisaged measurement
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ISO 17294-1:2004(E)
3.33
trueness
bias
closeness of agreement between the average value obtained from a large series of test results and an
accepted reference value
NOTE The measure of trueness is usually expressed in terms of bias, which equals the sum of the systematic error
components.
3.34
uncertainty of measurement
parameter, associated with the result of a measurement, that characterises the dispersion of the values that
could reasonably be attributed to the analyte concentration
4 Principle
ICP-MS stands for Inductively Coupled Plasma Mass Spectrometry. In the present context, a plasma is a
small cloud of hot (6 000 K to 10 000 K) and partly ionized (approximately 1 %) argon gas. Cool plasmas have
temperatures of only about 2 500 K. The plasma is sustained by a radio-frequency field. The sample is
brought into the plasma as an aerosol. Liquid samples are converted into an aerosol using a nebulizer. In the
plasma, the solvent of the sample evaporates, and the compounds present decompose into the constituent
atoms (dissociation, atomization). The analyte atoms are in most cases almost completely ionized.
In the mass spectrometer, the ions are separated and the elements identified according to their mass-to-
charge ratio, m/z, while the concentration of the element is proportional to the number of ions.
ICP-MS is a relative technique. The proportionality factor between response and analyte concentration relates
to the fact that only a fraction of the analyte atoms that are aspirated reach the detector as an ion. The
proportionality factor is determined by measuring calibration solutions (calibration).
5 Apparatus
5.1 General
The principal components of the ICP-mass spectrometer are as shown in Figure 1 in the form of a schematic
block diagram.
Figure 1 — Schematic block diagram of an ICP-mass spectrometer
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ISO 17294-1:2004(E)
5.2 Sample introduction
5.2.1 General
To introduce solutions to be measured into the plasma, a pump, a nebulizer and a spray chamber are
generally used. The pump supplies the solution to the nebulizer. In the nebulizer, the solution is converted into
an aerosol by an (argon) gas flow, except when an ultrasonic nebulizer is used; see 5.2.3. Large drops are
removed from the aerosol in the spray chamber by means of collisions with the walls or other parts of the
chamber and they are drained off as liquid. The resulting aerosol is then transferred into the plasma via the
injector tube of the torch (see 5.3) with the help of the nebulizer gas (sample-introduction gas).
The sample introduction system is designed in such a way that
a) the average mass per aerosol droplet is as low as possible;
b) the mass of the aerosol transported to the plasma in each period of time is as constant as possible;
c) the droplet size distribution and the added mass of the aerosol in each period of time is, as far as possible,
independent of the solution to be measured (matrix effect, see 6.3);
d) the time the aerosol takes to stabilize after introduction of a solution is as short as possible;
e) the parts of the system in contact with the sample or the aerosol are not corroded, degraded or
contaminated by the solution;
f) carry-over from one sample to subsequent samples is minimized.
The components of the sample introduction system shall be able to withstand corrosive substances that may
be in the solutions, such as strong acids. The material used for pump tubing should be resistant to dissolution
and chemical attack by the solution to be nebulized. Components that come into contact with the solution are
often made of special plastics. The use of glass and quartz shall be avoided if hydrofluoric acid is nebulized.
In those cases, the nebulizer, spray chamber and torch injector tube shall be made of suitable inert materials.
The various components of the sample introduction system are discussed hereafter in relation to the above
requirements and some “examples” are compared.
5.2.2 Sample pump
The use of a peristaltic pump to feed the solution to the nebulizer is not necessary with some nebulizers (see
5.2.3), but is desirable in almost all cases in order to render the supply of the solution less dependent on the
composition of the solution. A sampling pump is used on all modern instruments.
It is advisable to use a peristaltic pump having the largest possible number of rollers and a velocity as high as
possible to avoid major surges in the supply of the solution. The quantity of solution that is pumped is mostly
between 0,1 ml and 1,5 ml per minute.
5.2.3 Nebulizer
1)
The most common nebulizers are the concentric nebulizer [for example Meinhard ], the cross-flow nebulizer,
the V-groove nebulizer and the ultrasonic nebulizer (USN). The first one is self-aspirating, and the second one
can be, and these nebulizers can then be used without a pump (but seldom are). Nebulizers (except for the
USN) can be made of glass or of hard, inert plastic.
1) The Meinhard nebulizer is an example of a suitable product available commercially. This information is given for the
convenience of users of this part of ISO 17294 and does not constitute an endorsement by ISO of this product.
6 © ISO 2004 – All rights reserved
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ISO 17294-1:2004(E)
The concentric nebulizer consists of two concentric tubes, the outer one being narrowed at the end. The
solution flows through the central tube and the nebulizer gas (see 5.4) through the tube around it, creating a
region of lower pressure around the tip of the central tube and disrupting the solution flow into small droplets
(the aerosol). This nebulizer performs best with solutions with a low content of dissolved matter, although
there are also models that are less sensitive to significant amounts of dissolved matter in the solution to be
nebulized.
The cross-flow nebulizer consists of two capillary tubes mounted at a right angle, one being used for the
supply of the solution and the other for the supply of the nebulizer gas. Depending on the distance between
the openings of the capillary tubes and their diameters, the nebulizer can be self-aspirating. With larger
diameters, the chance of blockages occurring is of course smaller, but a pump will have to be used to supply
the solution.
In the V-groove nebulizer, the solution flows through a vertical V-groove to the outflow opening of the
nebulizer gas. The solution is nebulized by the high linear speed of this gas at the very small diameter outflow
opening. The V-groove nebulizer was developed for solutions with a high concentration of dissolved matter
and/or with suspended particles, although it is also used successfully with diluted and/or homogenous
2)
solutions. Similar nebulizers are the Burgener nebulizer and the cone-spray nebulizer, with similar outer
shapes as the concentric nebulizer. With these nebulizers, the solution flows out into a cone-shaped area at
the tip of the nebulizer instead of a V-groove and flows over the outflow opening of the nebulizer gas.
In the ultrasonic nebulizer, the solution is pumped through a tube that ends near the transducer plate that
vibrates at an ultrasonic frequency. The amount of aerosol produced (the efficiency) is typically 10 % to 20 %
of the quantity of the pumped solution. This is so high that the aerosol has to be dried (desolvated) before
being introduced into the plasma, which would otherwise be extinguished. The aerosol is transported to the
plasma by the nebulizer gas. Disadvantages of the ultrasonic nebulizer include its greater susceptibility to
matrix effects, diminished tolerance to high dissolved solid contents and a longer rinsing time.
For the other nebulizers described above, the efficiency is typically only a few percent. The efficiency
increases when the solution introduction rate is decreased. Specially designed concentric micro-nebulizers
made of special types of hard plastic operate at solution flow rates of 10 µl/min to 100 µl/min and efficiencies
approaching 100 %. These concentric micro-nebulizers often show a very good precision (low relative
standard deviation of the signal) and can also be combined with a membrane desolvator [see 6.2.1 a)].
Several other types of nebulizer may be used for specific applications.
5.2.4 Spray chamber
In the spray chamber [for example Scott (double concentric tubes), cyclonic or impact bead], the larger drops
of the aerosol are drained off in liquid form. To create and keep over-pressure in the chamber, the liquid shall
be removed via a sealed drain tube utilizing hydrostatic pressure or by pumping. The liquid shall be removed
evenly in order to avoid pressure variations in the chamber, which can result in variations in the signal.
By cooling the spray chamber to 2 °C to 5 °C, the water vapour formed in the nebulization process condenses,
thereby reducing the water load of the plasma. This results in a reduction in the formation of interfering
polyatomic ions (oxides); see 6.2.2.
5.2.5 Other systems
There are other types of introduction systems for particular applications. They include laser or spark ablation
of a solid sample, evaporation of the solution by means of a graphite furnace or a metal filament, introduction
of a gas or a gas form of the analyte (as in the hydride generation technique), systems for the direct
introduction of solid matter into the plasma (for example in the form of a slurry of a finely dispersed powder in
a solvent) and the introduction with a graphite rod directly into the plasma.
2) The Burgener nebulizer is an example of a suitable product available commercially. This information is given for the
convenience of users of this part of ISO 17294 and does not constitute an endorsement by ISO of this product.
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ISO 17294-1:2004(E)
With the Direct Injection Nebulizer (DIN), a pneumatic concentric micro-nebulizer, instead of the inner tube
(injector; see 5.3), is placed in the torch. It has a sample introduction efficiency of almost 100 % with a sample
uptake rate of typically 10 µl/min. A DIN can be used for techniques giving transient signals (for example
coupling to chromatographic or flow injection devices) and for minimizing the memory effects of, for instance,
boron, molybdenum and mercury.
These systems will not be discussed in this document.
5.3 Torch and plasma
The torch consists of three concentric tubes and can be designed as a single unit or a unit constructed of
independent parts. Quartz is the material generally used. Sometimes the innermost tube (the sample
introduction tube or injector tube) is made of inert material, for example aluminium oxide. It usually ends at
4 mm to 5 mm before the first winding of the coil. The aerosol produced in the sample introduction system
flows through the sample introduction tube, transported by an (argon) gas flow (the nebulizer gas) with a flow
rate of approximately (0,5 to 1,5) l/min.
The auxiliary gas flows between the sample introduction tube and the middle tube with a flow rate of 0 l/min to
3 l/min. Whether or not an auxiliary gas is used depends on the type of device concerned, the solvent used,
the salt concentration, etc. The function of the auxiliary gas is to increase the separation of the plasma and the
torch and thus reduce the temperature at the end of the injector (and intermediate) tube. This will avoid
deposits of dissolved material or the build-up of carbon (when organic solvents are nebulized) on the injector
tube.
The plasma gas flows between the midd
...
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