open systems - MS Spektrum

POSTĘP I KIERUNKI ROZWOJU
METOD PRZYGOTOWANIA PRÓBEK
W ANALITYCZNEJ SPEKTROMETRII
ATOMOWEJ
Sample Preparation and Presentation in Analytical
Atomic Spectrometry: Evolution and Future Trends
Henryk Matusiewicz
Politechnika Poznańska
Zakład Chemii Analitycznej
THE BEST METHOD
TO PREPARE THE SAMPLE
„ IS NOT TO PREPARE IT !
„
The ideal analytical method would employ no sample
preparation at all and transfer the analyte from the sample
directly into the analytical system. Unfortunately , such
direct methods are rare.
Pretreatment steps involved are most crucial and
generally are much more time-consuming than the
measurement sequence.
Most analytical atomic spectrometric techniques
require introduction of dissolved samples.
RELATIONSHIP BETWEEN SAMPLE PREPARATION AND DETERMINATION METHODS
METHODS THAT ALLOW
DIRECT SAMPLE ANALYSIS
METHODS THAT NEED
SAMPLE PREPARATION
X-ray Fluorescence
Neutron Activation
Thermogravimetry
Spectrographic
Gravimetry
Titrimetry
Spectrometry
Electro-analysis
Chromatography
Sample analysis is characterized by the interplay of at
least three domains of activity: sample preparaton, sample
introduction and instrumentation.
WET DIGESTION METHOD
This lecture gives an overview of the wet digestion
methods, one of the oldest and still most common and
frequently used techniques, for organic and inorganic
samples.
DIGESTION TECHNIQUE
REQUIRED REAGENTS
APPLICATION
OPEN SYSTEMS
Conventional heating
Microwave heating
Ultraviolet digestion
HNO3, HCl, HF, H2SO4 , HClO4 , H2O2 Inorganic / organic
HNO3, HCl, HF, H2SO4 , HClO4 , H2O2 Inorganic / organic
H2O2 , K2S2O8
Waters, slurries
CLOSED SYSTEMS
Conventional heating
Microwave heating
HNO3, HCl, HF, H2O2
HNO3, HCl, HF, H2O2
FLOW SYSTEMS
Conventional heating
HNO3, H2SO4 , H2O2
UV on-line decomposition H2O2 , K2S2O8
HNO3, H2SO4 , H2O2
Microwave heating
VAPOR-PHASE
ACID DIGESTION
HNO3, HCl, HF, H2O2
Inorganic / organic
Inorganic / organic
Inorganic / organic
Waters, slurries ?
Inorganic / organic
Inorganic / organic
WET DIGESTION METHOD
SUMMARY OF APPLICATION OF TOTAL WET DIGESTION PROCEDURES TO THE
ANALYSIS OF MATERIALS (DETERMINATION OF ELEMENTS)
MATERIAL/MATRIX/SAMPLE
REQUIRED ACID(S)
DIGESTION TECHNIQUE
(MODE)
WATER(S)
H2O2, HNO3
UV radiation
ENVIRONMETAL SAMPLES
Coal
Coal fly ash
Dust
Catalysts
HNO3, HCl, HF
Aqua regia + HF
Aqua regia + HF
Aqua regia
open or closed system
open or closed system
open or closed system
open system
WASTE MATERIALS
Sewage sludge
Waste water
HNO3, HCl
HNO3
open or closed or flow system
flow system
FORENSIC
HNO3
open or closed system
FOOD(S)
HNO3
open or closed system
BEVERAGES
HNO3, H2O2
open or closed or flow system
WET DIGESTION METHOD
(CONT.)
MATERIAL/MATRIX/SAMPLE
REQUIRED ACID(S)
DIGESTION TECHNIQUE
(MODE)
BIOLOGICAL SAMPLES
Botanicals
Plants
Clinical
Marine
HNO3 + H2O2 + HF
HNO3 + H2O2 + HF
HNO3
HNO3
open or closed system
open or closed system
open or closed system
open or closed system
POLYMERS
HCl, HNO3, HF, H2SO4
open or closed systems
SILICATES
Soils
Sediments
Glasses
Aqua regia + HF
Aqua regia + HF
HF
open and/or closed systems
open and/or closed systems
open systems
GEOLOGICAL SAMPLES
Rocks
Ores
Minerals
Aqua regia + HF
Aqua regia + HF
HF + H2SO4 + HCl
open or closed systems
open or closed systems
open systems
WET DIGESTION METHOD
(CONT.)
MATERIAL/MATRIX/SAMPLE
REQUIRED ACID(S)
DIGESTION TECHNIQUE
(MODE)
PETROLUM PRODUCTS
Fuels
oils
HNO3 + HCl
HNO3 + HCl
open or closed system
open or closed system
DRUG / PHARMACEUTICALS
HCl, HNO3
open systems
METALS
Ferrous
Non-ferrous
Alloys
Steels
HNO3+ (HF or HNO3 or H2SO4)
HCl or HNO3 or HF
Aqua regia + HF
HCl or HNO3, HClO4
open systems
open systems
open systems
open systems
CHEMICALS
HCl, HNO3, HF, H2SO4
open or closed systems
REFRACTORY COMPOUNDS
Ceramics
Composites
HNO3, HCl, HF, H2SO4, H2O2
HNO3, HCl, HF, H2SO4, H2O2
open or closed systems
open or closed systems
NUCLEAR MATERIALS
HNO3 or HCl, H3PO4, HClO4
open or closed systems
WET DIGESTION METHOD
•
•
•
•
•
•
•
Other sample preparation
methods, such as:
chemical extraction and leaching
enzymatic decomposition
anodic oxidation
dry ashing
fusion
sonication
etc.,
are beyond the scope of this
contribution and will not be
discussed here.
WET DIGESTION METHOD
PHISICAL PROPERTIES OF COMMON MINERAL ACIDS
AND OXIDIZING AGENTS USED FOR WET DIGESTION
MOLECULAR
COMPOUND FORMULA
WEIGHT
BOILING
DENSITY
COMMENTS
POINT
(kg / l)
MOLARITY
(oC)
CONCENTRATION
w / w (%)
Nitric acid
HNO3
63.01
68
16
1.42
122
68% HNO3,
azeotrope
Hydrochloric
acid
HCl
36.46
36
12
1.19
110
20.4% HCl,
azeotrope
Hydrofluoric
acid
HF
20.01
48
29
1.16
112
38.3% HF,
azeotrope
Perchloric
acid
HClO4
100.46
70
12
1.67
203
72.4% HClO4,
azeotrope
Sulfuric acid
H2SO4
98.08
98
18
1.84
338
98.3% H2SO4
Phosphoric
acid
H3PO4
98.00
85
15
1.71
213
Decomposes
to HPO3
Hydrogen
peroxide
H2O2
34.01
30
10
1.12
106
WET DIGESTION METHOD
PREFERRED MATERIALS FOR WET DIGESTION VESSELS
AND THEIR USE FOR TRACE ELEMENT DETERMINATIONS
MATERIAL
CHEMICAL
NAME
Borosilicate
SiO2
glass
Fused
quartz
SiO2
WATER
WORKING
ABSORPTION
TEMP. (OC)
(%)
COMMENTS
< 800
Ordinary laboratory glass
is not suitable for use in
wet digestion procedures
< 1200
For all procedures
involving wet digestion of
organic material, quartz is
the most suitable material
for vessels
Glassy carbon is used in
the form of crucibles and
dishes for alkaline melts
and as receptacles for wet
digestion procedures
Glassy
carbon
Graphite
< 500
PE
polyethylene
< 60
PP
polypropylene < 130
< 0.02
WET DIGESTION METHOD
(CONT.)
MATERIAL
CHEMICAL
NAME
WATER
WORKING
ABSORPTION
TEMP. (OC)
(%)
PTFE
Polytetrafluorethylene
< 250
< 0.03
PFA
Perfluoralkoxy
< 250
< 0.03
FEP
Tetrafluorpere< 200
thylene
< 0.01
TFM
Tetrafluormetoxil
< 0.01
< 250
COMMENTS
PTFE is generally used
only for digestion vessels
in pressure digestion
systems
WET DIGESTION METHOD
ELEMENT CONCENTRATION IN LABORATORY AIR DUST
IN AN ORDINARY LABORATORY,
IN A CLEAN ROOM AND IN A CLEAN HOOD
ELEMENT CONCENTRATION (µg/m3)
Fe
Cu
Pb
Cd
0.2
0.02
0.4
0.002
CLEAN ROOM
0.001
0.002
0.0002
n.d.
CLEAN HOOD
0.0009
0.007
0.0003
0.0002
ORDINARY LABORATORY
WET DIGESTION METHOD
In past years, sample digestion has been considered as
an achilles’ heel in the analytical sequence. Consequently,
sample digestion is often regarded as a weak link in
sample analysis that provides much scope for
improvement.
„
Since the beginning of the 1970s, a large increase of
general interest in different digestion techniques and in
publication dedicated especially to wet digestion methods
has been evident.
WET DIGESTION METHOD
OPEN SYSTEMS
Open vessel acid digestions, one of the oldest
techniques, are undoubtely the most common method of
sample decomposition or dissolution of organic and
inorganic sample materials used in chemical laboratories.
¾ CONVENTIONAL HEATING
(THERMALLY CONVECTIVE WET DIGESTION)
OPEN SYSTEMS
However, when a sample is decomposed by open wet
digestion, refluxing is compulsory. The necessary
apparatus has been described by
„ P.O.Bethge, Anal.Chim.Acta, 10, 317 (1954)
OPEN SYSTEMS
¾ MICROWAVE HEATING
(MICROWAVE - ASSISTED WET DIGESTION)
The most innovative source of energy for wet digestion
procedure is MICROWAVES.
„
Analytical chemist first began
using microwave techniques
to wet digestion of biological
samples in 1975 (the first paper
published on microwave-assisted
digestion).
OPEN SYSTEMS
A.Abu-Samra, J.S.Morris,
S.R.Koirtyohann, Anal.Chem.,
47, 1475 (1975)
The focused-microwave-assisted
system is primarily used for
„ atmospheric pressure digestions.
„
OPEN SYSTEMS
¾ ULTRAVIOLET DIGESTION (PHOTOLYSIS)
Ultraviolet (UV) digestion is utilized mainly in water
matrices (aqueous solution). Liquids are decomposed by
UV radiation in the presence of small amounts of hydrogen
peroxide, acids (mainly HNO3) or peroxodisulphate. In
photolysis, the digestion mechanism can be characterized
by the formation of OH* radicals from both water and
hydrogen peroxide that is initialized by the aid of the UV
radiation.
OPEN SYSTEMS
WET DIGESTION METHOD
CLOSED SYSTEMS
During the last few decades, methods of wet sample
preparation using closed vessels have become widely
applied. Closed systems offer the advantage that the
operation is essentially isolated from the laboratory
atmosphere, thereby minimizing contamination (closed
digestion system is particularly suitable for trace and
ultratrace analysis).
CLOSED SYSTEMS
¾ CONVENTIONAL HEATING
(THERMALLY CONVECTIVE WET PRESSURE
DIGESTION)
The digestion of inorganic and organic substances in
sealed tubes was the method first proposed for pressure
digestion at the end of 19th century, and some of these
applications are still difficult to replace by other digestion
methods.
„ The use of sealed glass tubes goes back to
„ A.Mitscherlich, J.Prakt.Chem., 81, 108 (1860) and
L.Carius, Justus Liebigs Ann.Chem., 116 (1860)
„ Often referred to as the Carius’Technique, first
described in 1860.
„
CLOSED SYSTEMS
CLOSED SYSTEMS
Digestion in autoclaves with metal inner reaction
vessels was originally proposed in 1894
„ P.Jannasch, Z.Anorg.Allgem.Chem., 6, 72 (1894)
„ Extensive use of pressure digestion in analytical
procedures began in 1960.
CLOSED SYSTEMS
Most sample vessels
for use in thermally
convective pressure
digestion are
constructed from PTFE,
PFA, PVDF or quartz
and glassy carbon.
J.Ito, Bull.Chem.Soc.Jpn., 35, 225 (1962)
F.J.Langmyhr, S.Sveen, Anal.Chim.Acta., 32, 1 (1965)
B.Bernas, Anal.Chem., 40, 1682 (1968)
CLOSED SYSTEMS
G.Knapp, Fresenius Z.Anal.Chem., 317, 213 (1984)
CLOSED SYSTEMS
¾ MICROWAVE HEATING
(MICROWAVE-ASSISTED PRESSURIZED
WET DIGESTION)
Closed-vessel microwave-assisted digestion technology
has been acknowledged as one of the best solutions for
clean chemistry applications and has a unique advantage
over other closed-vessel technologies.
CLOSED SYSTEMS
The inspiration for pressure digestion studies came
from a US Bureau of Mines Raport.
„ S.A. Matthes et al., Techn. Prog. Rep., 120, 9 (1983)
CLOSED SYSTEMS
„MICROWAVE TEFLON BOMB”
Microwaves only heat the
liquid phase, while vapors do
not aborb microwave energy.
CLOSED SYSTEMS
It was developed a focused-microwave-heated bomb
that would exceed the operational capabilities of existing
microwave digestion systems and permit the construction
of an integrated microwave source / bomb combination.
„ H.Matusiewicz, Anal.Chem., 66, 751 (1994)
WET DIGESTION METHOD
FLOW SYSTEMS
Continuous flow-through thermal digestion,
UV digestion, and microwave digestion systems were
designed to overcome some of the limitations by replacing
the vessels with flow-through tubing (coil).
„
Samples are digested by pumping them through a coil
containing a digestion matrix while being heated by
ƒ thermal
ƒ UV
ƒ microwave
FLOW SYSTEMS
¾ CONVENTIONAL HEATING (THERMAL)
„
„
System presented by
T.J.Gluodenis, J.F.Tyson, J.Anal.At.Spectrom.,
7, 301 (1992)
FLOW SYSTEMS
¾ UV ON-LINE DECOMPOSITION
UV digestion is a clean sample preparation method,
as it does not require the use of large amounts of oxidants.
Furthermore, UV digestion is effective and can be readily
incorporated into flow injection manifolds.
FLOW SYSTEMS
¾ MICROWAVE HEATING
(MICROWAVE-ASSISTED PRESSURIZED
FLOW-THROUGH DIGESTION)
The earliest work reported in this field was by
M.Burguera et al., Anal.Chim.Acta, 179, 351 (1986)
who applied a flow injection system for on-line
decomposition of samples.
FLOW SYSTEMS
An „ideal” continuous flow and stopped flow digestion
system was presented by
V.Karanassios et al., J.Anal.At.Spectrom., 6, 457 (1991)
WET DIGESTION METHOD
VAPOR-PHASE
ACID DIGESTION
(GAS-PHASE REACTION)
An alternative approach
to acid digestion of the
sample matrix that prevents
introduction of impurities
exploits gas-phase reaction.
VAPOR-PHASE ACID DIGESTION
A more vigorous treatment involves bomb digestion in
pressure vessels designed to incorporate the techniques
of a closed pressure vessel and vapor-phase digestion
in a single unit.
Heating can be accomplished in an ordinary oven (with
conductive heating)
1 STAINLESS STEEL BODY
2 PTFE VESSEL
3 PTFE ADAPTER
a REACTION VESSEL
b MICROSAMPLING DEVICE
VAPOR-PHASE ACID DIGESTION
or using a microwave field.
WET DIGESTION METHOD
¾ EFFICIENCY OF WET DIGESTION
(DECOMPOSITION AND DISSOLUTION)
PROCEDURES
Comlete digestion of the sample is required to achieve
reproducible and accurate elemental results by
instrumental analytical techniques (AAS, AFS,
ICP/MIP/ DCP – OES ).
The most important criterion for the sample
decomposition is a sufficient destruction of the organic
matrix.
In order to investigate the completeness of dissolution
of inorganic materials, the recovery (or incomplete) and
accuracy of major, minor and trace element determination
are usually applied.
In principle, temperature, sample mass and digestion
time determine the effectiveness of a digestion.
EFFICIENCY OF WET DIGESTION
EFFICIENCY OF WET DIGESTION
Good agreement between microwave heated ashing
system and a traditional thermal acid decomposition
procedure in a quartz bomb can be obtained.
RESIDUAL CARBON
DIGESTION SAMPLE FINAL VOL,
MASS, g
mL
METHOD
EFFICIENCY
DIGESTION
IN
IN
OF OXIDATION
TIME,
DIGESTATE, DRY SAMPLE,
%
min
mg
/
g
µg / mL
MICROWAVE
HEATED
BOMB
0.1
10
4
30 ± 3
3 ± 0.3
99.4
HIGH
PRESSURE
ASHER
0.1
10
120
20 ± 2
2 ± 0.2
99.6
RESIDUAL CARBON CONTENT IN DIGESTED SAMPLES
OF BOVINE LIVER ( NIST-SRM 1577 a )
WET DIGESTION METHOD
ADVANTAGES AND DISADVANTAGES OF WET DIGESTION METHODS
DIGESTION
TECHNIQUE
OPEN
SYSTEMS
Conventional
heating
POSSIBLE
WAY
OF LOSSES
SAMPLE SIZE (g)
SOURCE
OF BLANK ORGANIC INORGANIC
MAXIMUM
TEMP.
(oC)
PRESSURE
(bar)
DIGESTION
TIME
volatilization
acids,
<5
vessels, air
< 10
< 400
several
hours
Microwave
heating
volatilization
acids,
<5
vessels, air
< 10
< 400
< 1h
UV digestion
none
< 90
several
hours
CLOSED
SYSTEMS
Conventional
heating
Microwave
heating
liquid
retention
acids (low) < 0.5
<3
< 320
< 150
several
hours
retention
acids (low) < 0.5
<3
< 320
< 200
< 1h
WET DIGESTION METHOD
(CONT.)
DIGESTION
TECHNIQUE
POSSIBLE
WAY
OF LOSSES
SAMPLE SIZE (g)
SOURCE
OF BLANK ORGANIC INORGANIC
MAXIMUM
TEMP.
(oC)
PRESSURE
(bar)
DIGESTION
TIME
FLOW
SYSTEMS
Conventional
heating
incomplete
digestion
acids (low)
< 0.1
(slurry)
UV on-line
digestion
incomplete
digestion
none
liquid
Microwave
heating
incomplete
digestion
acids (low)
< 0.1
(slurry)
< 0.3
(slurry)
< 250
< 40
several
minutes
none
none
< 0.1
< 0.1
< 200
< 20
< 1h
VAPORPHASE
ACID
DIGESTION
< 0.1
(slurry)
< 320
> 300
several
minutes
several
minutes
< 90
WHERE IS SAMPLE PREPARATION
„ HEADED?
¾ HIGH-TEMPERATURE (360 OC) /
HIGH-PRESSURE (300 bar) FLOW SYSTEM
FOR ON-LINE SAMPLE DIGESTION
Q.Z.Bian et al., Anal.Chim.Acta., 538, 323 (2005)
¾ MICROWAVE-ENHANCED FLOW SYSTEM
FOR HIGH-TEMPERATURE (250 OC) /
HIGH-PRESSURE (40 bar)
SAMPLE DIGESTION
„
U.Pichler et al., Anal.Chem., 71, 4050 (1999)
COMBINED DIGESTION
TECHNIQUES
(A NEW RESEARCH FIELD)
¾ OXIDATION OF ORGANICS IN WATER
SOLUTION BY OZONE COMBINED
WITH ULTRAVIOLET RADIATION
¾ OZONATION; OZONE / UV; UV / H2O2
DEGRADATION OF ORGANICS
¾ UV-PHOTOCATALYTIC OXIDATION
OF ORGANICS WITH TiO2 CATALYSTS
¾ OZONE DEGRADATION OF ORGANICS
USING MICROWAVE IRRADATION
¾ INTEGRATED MICROWAVE / UV
PHOTOCATALYZED / TiO2
DECOMPOSITION OF ORGANICS
S.Horikoshi et al., J.Photochem.Photobiol., 161, 221 (2004)
¾ HIGH-TEMPERATURE / HIGH-PRESSURE,
MICROWAVE-ASSISTED UV SAMPLE
DIGESTION
This technique combines the
benefits of pressurized
microwave-assisted digestion
(70 bar) with those observed
for UV decomposition.
D.Florian, G.Knapp, Anal.Chem., 73, 1515 (2001)
¾ HIGH-TEMPERATURE / HIGH-PRESSURE,
MICROWAVE-ASSISTED UV SAMPLE
DIGESTION
molybdenum
foil
tungsten wire
Cd lamp
This technique combines the benefits of high
temperature ( 320 oC) / high pressure (130 bar)
microwave-assisted UV sample digestion.
¾ ULTRASOUND ASSISTED MICROWAVE
DIGESTION
Simultaneous microwave and ultrasound irradiation for
digestion of solid and liquid samples.
S.Chemat et al., Ultrasonics Sonochem., 11, 5 (2004)
Analytical atomic spectrometric techniques are still a
most appropriate techniques for elemental determinations
ƒ
Atomic Absorption Spectrometry (AAS)
ƒ
Plasma Optical Emission Spectrometry (OES)
ƒ
Atomic Fluorescence spectrometry (AFS)
mainly due to its simplicity and low cost.
Solution nebulization or liquid sample aliquoting are the
most common methods for introducing sample into atomic
spectrometers.
PROCESSES IN A FLAME / PLASMA
Is it still possible, necessary and beneficial to perform
research in analytical atomic spectrometry?
AAS
FLAME
ICP DISCHARGE
AFS
GDL DISCHARGE
GF
MIP DISCHARGE
CMP DISCHARGE
DCP DISCHARGE
LIQUID-SAMPLE
INTRODUCTION TECHNIQUES
¾ PNEUMATIC NEBULIZATION
CONCENTRIC NEBULIZER
CROSS-FLOW NEBULIZER
FRITTED-DISC NEBULIZER
VEE-GROOVE NEBULIZER
GRID-TYPE NEBULIZER
¾ ULTRASONIC NEBULIZATION
¾ THERMOSPRAY
¾ JET IMPACTION
¾ NEBULIZER / SPRAY CHAMBER /
DESOLVATION SYSTEM
¾ HYDRIDE GENERATION TECHNIQUE
BATCH
CONTINUOUS
purge
sample/acid
gas
and
purge gas
reductant
reductant
detector
detector
sample/
acid
waste
sample
FLOW INJECTION
injection valve detector
acid
reductant
purge
gas
reaction
coil
gas-liquid separator
waste
¾ COLD VAPOR TECHNIQUE
BATCH SYSTEM FOR MERCURY COLD VAPOR GENERATION
¾ MICROFLOW – SCALE NEBULIZERS
ƒ
ƒ
ƒ
ƒ
ƒ
microconcentric
high efficiency
direct injection
micro – mist
micro – ultrasonic
¾ FLOW INJECTION ANALYSIS
FUTURE TRENDS
New technology for continuous monitoring and
controlling microwave reaction progress:
ƒ temperature
ƒ pressure
pressure (bar)
incident power (W)
ƒ incident energy
o
temperature ( C)
reflected power (W)
ƒ reflected energy
„
300
and
in situ
microwave-assisted
digestion
250
(bar)
(oC)
(W)
200
150
100
50
0
0
200
400 600
800 1000 1200 1400
time (s)
FUTURE TRENDS
¾ MULTIDIMENSIONALITY
(COUPLING TECHNIQUES)
Tandem sources have been implemented in an efford to
realize ideal capabilities, where two (or three) separately
operable sources are coupled to take advantage of the
optimum attributes of each.
FUTURE TRENDS
HYPHENATED VAPOR GENERATION
ATOMIC SPECTROMETRIC TECHNIQUES
¾ HYPHENATED TECHNIQUE
HG IN SITU TRAPPING F-AAS
FUTURE TRENDS
NEW DEVELOPMENTS IN HYDRIDE
GENERATION – ATOMIC SPECTROMETRY
¾ SIMULTANEOUS DETERMINATION OF HYDRIDE
FORMING ELEMENTS WITH „NORMAL”
ELEMENTS IN A SINGLE ANALYTICAL RUN
FUTURE TRENDS
¾ HYPHENATED TECHNIQUES
COMPONENT DIAGRAM OF THE ELABORATED HG-ETV-MIP-OES SYSTEM
FUTURE TRENDS
’’ High – resolution continuum source AAS: the better
way to perform atomic absorption spectromerty”.
Bernard Welz
INSTRUMENTAL CONCEPT FOR HR-CS AAS
FUTURE TRENDS
FUTURE TRENDS
In vivo sample uptake and on-line sample digestion
combined with flow injection system.
M.Burguera et al., J.Anal.At.Spectrom., 10, 343 (1995)
FUTURE TRENDS
¾ NANOTECHNOLOGY
Microscale chemistry could reduce the volume of
reagents, consumption of sample and generation of waste
by several orders of magnitude. Miniaturization of
instrumentation (microanalysis systems) compliments this
drive.
The fact that miniaturized
chips would be coupled to fullsized spectrometers should
not detract from this
profitability.
CONCLUSION
Microwave sample preparation will become a standard
laboratory tool, similar to analytical atomic spectrometry,
and will have as many varieties of specialized equipment
as these earlier analytical staples.
Analytical chemists no longer have to accept the
technological mismatch between sample preparation and
analytical atomic spectrometric instrumentation.
FAR FUTURE
DIGESTION SYSTEM-HIGH-PERFORMANCE SPECTROMETER
(AAS / AFS / ICP / MIP / DCP / XXX / YYY / …?
Methodological blank problem? Owing to our inability
to control contamination and, hence, the method blank.
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