Special
Issue on 50 Years of Analytical Chemistry in Uranium Exploration
in AMD
A
comparative study of the uranium fluorescence behaviour in optical
and laser fluorimetry in the presence of metals: Uranium determination
at trace level in lanthanum, cerium, yttrium and thorium
A
single stage simultaneous separation and pre concentration of
rare earth elements on activated carbon for its determination by
ICP-OES
after wet ashing - Application to soil samples
G.Chakrapani,
P.L.Mahanta, V.V.Hanuman and P.K.Srivastava
Separation,
preconcentration and estimation of rare earth and trace elements
by inductively coupled plasma-atomic emission spectrometry (ICP-AES)
in thorium matrices
Prithwish
Chakraborty, Vijay Kumar, Smeer Durani and K.Satyanarayana
Determination
of phosphate in water samples by vanadomolybdates method in presence
of silica using UV-visible spectrophotometer - A study of the effect
of acid concentration
2-Thenoyl
trifluoroacetone (TTA) functionalized Amberlite XAD-2: A newly
designed chelating resin for enrichment of Cu(II), Cd(II), Co(II),
Ni(II), Pb(II), Zn(II), Mn(II), Fe(III) from water prior to their
determination by flame-AAS and UO(II) by fluorimetry. A green analytical
method
Solvent
extraction of zirconium(iv) and hafnium (iv) with the neutral ligand
1-phenyl -2,3 dimethyl -5pyrazolone in presence of perchlorate
as the anion
A
new sample solution preparation method for columbite - tantalite
minerals using lithium metaborate fusion: ICP-AES determination
of Nb, Ta, Ti, Fe, Mn, Zr, W, Sn, Al, Si, Ca, Mg, Na, K, REE, Y
and U
A
COMPARATIVE STUDY OF THE URANIUM FLUORESCENCE BEHAVIOUR IN OPTICAL
AND LASER FLUORIMETRY IN THE PRESENCE OF METALS: URANIUM DETERMINATION
AT TRACE LEVEL IN LANTHANUM, CERIUM, YTTRIUM AND THORIUM
A.Premadas1 and G.Saravanakumar2
Chemistry
Laboratory
Atomic
Minerals Directorate for Exploration and Research
The
paper presents the data on the quenching behaviour of certain metals
on uranium fluorescence both
in solid and aqueous phases recorded using an optical fluorimeter and
the Laser Induced Fluorimeter (LIF) respectively. The result shows
that LIF has very good tolerance for the rare earth elements (REEs),
Y and Th as compared to an optical fluorimeter. On this basis a simple
and rapid procedure is developed for the direct LIF determination of
uranium in the oxides of La, Ce, Y and Th, and it can be applied to
other REEs also, and the determination limit is 10 mg g-1 . The proposed
procedure is useful for the determination of uranium in rare earth
elements and thorium oxides produced commercially from monazite mineral.
After the selective solvent extraction separation of uranium from the
oxides of La, Ce, Y and Mn, using a mixture of mono and bis-(2-ethylhexyl)
phosphate as solvent from 2M HCl medium, the determination limit of
uranium is brought down up to 0.2 mg g-1 in the oxides of La, Ce, Y
and Mn. The accuracy of the method is fairly good (± 7% error)
offering the RSD of 4 to 7%.
Key-words:
Uranium, Fluorescence, Quenching, Determination in La, Ce, Y and Th.
APPLICATION
OF LASER FLUORIMETRY IN URANIUM EXPLORATION - DETERMINATION OF URANIUM
IN LITHO GEOCHEMICAL SAMPLES
C.R.Khorge,
V.V.Hanuman, G.Chakrapani and P.K.Srivastava
Chemical
Laboratory
Atomic
Minerals Directorate for Exploration and Research
Department
of Atomic Energy
AMD
Complex, Civil Lines, Nagpur 440001
Abstract
A simple and rapid laser fluorimetric
method is described for the determination of uranium at ppm level in
litho geochemical samples of diverse matrices. The method is developed
using ortho phosphoric acid as fluorescence enhancing reagent. The
main advantage of the method is the high tolerance for inorganic quenchers,
as compared to other reagents such as polyphosphate, pyrophosphate
buffers that works in neutral medium. The optimum concentration of
ortho phosphoric acid required and the quenching behaviour of some
common major and minor elements were studied. Uranium can be determined
down to 0.5 ppm level by standard addition method in normal rock and
soil samples.
The validity of the procedure is checked with CRMs viz., SO-2, SO-3,
SO-4 and MRG-1 and also with synthetic mixtures of composition conforming
to acidic, basic and ultra basic rocks. The accuracy and reproducibility
of this method are good with RSD ~ 5 % (n=8 for MRG– 1). This method
was successfully applied to litho geochemical samples received from
various investigation groups of AMD.
LIQUID-SOLID
EXTRACTION OF URANIUM (VI) WITH TOPO - MOLTEN NAPHTHALENE AND DETERMINATION
BY LASER FLUORIMETRY IN GEOLOGICAL SAMPLES
Sanjay
Kumar1,
M.Krishnakumar1 and A.A.Patwardhan2
Chemistry
Laboratory,
Atomic
Minerals Directorate for Exploration and Research
Department
of Atomic Energy
1Shillong
- 793 011, 2Nagpur-440001
Abstract
A
simple, rapid, sensitive, cost-effective and efficient method for
separation of uranium using tri-n-octylphosphine
oxide (TOPO)-molten naphthalene as solid phase extractant and its determination
by laser fluorimetry in geological samples (rock, soil, sediment) was
developed. Under optimum conditions, using 50 mg TOPO and 100 mg naphthalene,
50 - 5000 ng of uranium in 10 mL sample solution (3 % (v/v) HNO3) could
be extracted quantitatively. The extracted uranium was stripped using
tetra sodium pyrophosphate (5% (v/v) solution, pH adjusted to 7.0 with
H3PO4) and determined by laser fluorimetry. The influence of different
acid concentrations, the amount of solid phase extractant, sample volumes,
different stripping reagents, their volumes and effect of foreign ions
on the extraction and determination of uranium (VI) were investigated.
Synthetic samples of varying concentration as regards uranium were
prepared and analysed. Recoveries ranging from 90 % to 105 % were obtained.
The method was validated by analyzing four certified reference materials
namely, BL-5, DH-1a, SY-2, SY-3 and the values obtained for uranium
agreed well with the certified values. The method was also applied
to the determination of uranium in geological samples (rock, soil and
sediment) by laser fluorimetry and the results obtained compared favorably
with those obtained from the pellet fluorimetry method. Following the
proposed method, determination limit for uranium was found to be 1 µg/g
with RSD ± 10 %.
DETERMINATION
OF URANIUM BY INDUCTIVELY COUPLED PLASMA OPTICAL EMISSION SPECTROMETRY
R.Lalithambal,
P.K.Bhargava, G.S.Chowdary and Adarsh Kumar
Chemistry
Laboratory, Northern Region,
Atomic
Minerals Directorate for Exploration and Research
Department
of Atomic Energy
New
Delhi
Abstract
Uranium
was determined by ICP-OES using 409.014nm emission line. When present
in quantities greater than
100 ppm, a sample solution of 1.0 gram in 100 ml was aspirated directly
into the plasma without separation of Uranium from the matrix elements.
If the uranium content of the sample is less than 100 ppm, uranium
was separated from the matrix by extracting it into ethyl acetate;
an aliquot of organic extract is evaporated, taken in nitric acid and
aspirated into argon plasma. 1 µg/g of uranium in sample can
also be determined.
FERRIC
HYDROXIDE GEL, GOETHITE AND HUMIC ACID GEL AS SOLID PHASE ADSORBENTS
FOR URANIUM AND THEIR THERMOANALYTICAL STUDIES
G.Suryaprabhavathy,
S.Charulata and D.S.R.Murty
Chemistry
Laboratory,
Atomic
Minerals Directorate for Exploration and Research
Begumpet,
Hyderabad
Abstract
Radioactive sand stone samples of
sedimentary rocks constitute fine particles like clays, hydrous iron
oxides (goethite) and humic acid. All these colloidal particles have
the property of sorption, ion-exchange etc. under suitable conditions.
Hence the ability of these fine particles for uranium sorption and
retention has been investigated in detail individually on ferric hydroxide
gel, goethite and humic acid gel and the thermoanalytical studies were
also carried out.
Freshly precipitated ferric hydroxide gel exhibited uranyl sorption upto 9%.
Natural and synthetic goethite showed upto 2.8%, and humic acid upto 6% under
optimum conditions of pH and uranyl concentration. Differential thermal analysis
was carried out to characterise ferric hydroxide gel, natural and synthetic goethite
and humic acid gel.
BIOSORPTION
OF URANIUM FOR SEPARATION/ PRECONCENTRATION PRIOR
TO ITS ESTIMATION BY FLUORIMETRY
Leela
Gopal, M.A.Nayeem and D.S.R.Murty
Chemistry
Laboratory,
Atomic
Minerals Directorate for Exploration and Research
Department
of Atomic Energy
Begumpet,
Hyderabad
Abstract
Investigations have been carried
out extensively for separation/ pre-concentration of uranium from aqueous
solutions using inexpensive baker’s yeast. Various experimental parameters
have been optimized for complete solid phase adsorption of uranium
and its final recovery. The adsorption on baker’s yeast is quantitative
from 1.0 pH onwards but decreases drastically below 1 pH. The effect
of amount of baker’s yeast, contact time, pH, volume of aqueous solution,
the presence of various cations and anions and reagents for desorption
are optimized. As the uranium carbonate complexes are very strong in
solutions, the carbonate reduces the uranium adsorption from pH 4 and
above. Maximum uranium recovery from the baker’s yeast is observed
by ignition and treatment with nitric acid.
Keywords: Biosorption, Baker’s yeast, Fluorimetry
PERFORMANCE
EVALUATION OF VARIOUS CHEMICAL ANALYTICAL METHODS FOR THE ACCURATE
DETERMINATION OF U3O8 IN
YELLOW CAKE
P.K.Tarafder,
K.R.K.Sarma and P.K.Ghosh
Chemistry
Laboratory,
Atomic
Minerals Directorate for Exploration and Research
Department
of Atomic Energy
Khasmahal
P.O., Tatanagar, Jamshedpur
Abstract
A Yellow cake (Magnesium Diuranate,
MgU2O7) sample was analysed by a host of available gravimetric, titrimetric,
fluorimetric and spectrophotometric methods and its uranium oxide content
determined. Gravimetric methods applied were diuranate precipitation
followed by its ignition to U3O8; homogeneous precipitation as phosphate
and its ignition to pyrophosphate; oxine precipitation followed by
its ignition to U3O8 and peroxyuranate precipitation followed by its
ignition to U3O8 were applied. Other methods like redox titration with
dichromate, H2O2 spectrophotometry and pellet as well as Laser fluorimetry,
etc. were also applied. The results obtained using the above methods
were compared. While the results obtained from most of the methods
studied, compared favorably, those obtained from the redox titration
(Florence method) was found to be incongruent.
The present paper describes the systematic studies carried out to evaluate
the performance of different chemical analytical methods for the estimation
of uranium in MgU2O7 sample.
APPLICATION
OF DIFFERENT SELECTIVE EXTRACTIONS IN URANIUM EXPLORATION GEOCHEMISTRY
Usha
Nathan
Chemistry
Laboratory, Southern Region
Atomic
Minerals Directorate for Exploration and Research
Department
of Atomic Energy
Nagarbhavi,
Bangalore
Abstract
Analysis of soil and sediment samples
to quantify the uranium present, using selective extraction methods
to distinguish different phases, is of particular interest in uranium
exploration geochemistry to locate deeply buried mineral deposits.
Phases present in soils and sediments which are likely to scavenge
‘free’ elements include amorphous Mn and Fe oxides, the humic and fulvic
components of humus and clays. In this paper, different selective reagents
were applied to extract uranium from the different phases in all the
types of weathered rocks of Lalbarra, Nainpur District, Madhya Pradesh.
These values helped in quantifying the physico-chemical parameters
responsible for the formation of uranium deposits. Major mineralized
litho units in Lalbarra area are 1) carbonatised and silicified Lametas
specially sandstone 2) Hematised and goethised (oxidized) amygdular
basalts and massive basalts 3) iron rich silicified rocks and iron
poor silicified rocks. The selective reagents used were sodium pyrophosphate,
ammonium acetate, sodium carbonate, ammonium oxalate and nitric acid.
Compared to ammonium acetate reagent at pH 4.5, the Na2CO3+H2O2 at
pH 8.3 showed higher uranium leachability in all the litho units clearly
indicating that uranium mineralization was associated with silicification.
The leachable uranium using Na4P2O7 reagent at pH 10 in the infratrappeans,
massive basalts and the amygdular basalts showed that uranium was associated
with organically chelated iron. High uranium leachability with ammonium
oxalate reagent at pH 3.3 confirmed that uranium was hosted in iron
oxides.
PRECONCENTRATION
STUDIES OF REE ON CHITIN AND SAWDUST
Anitha
Mary Thomas and *D.S.R.Murty
Atomic
Minerals Directorate for Exploration and Research
Department
of Atomic Energy
Nagarbhavi,
Bangalore, *Begumpet, Hyderabad
Abstract
Determination of rare earth elements
by ICP – AES has been attempted after their preconcentration on Chitin,
a biopolymer and also on Sawdust. Various adsorption desorption parameters
are optimised. REE’s are sorbed at pH 4 and recovered by heating with
5% HNO3. The possible mechanism of sorption is surface adsorption .The
method is applied on selected rock samples like barytes, calcites and
water samples.
Key words: REE, preconcentration, chitin, sawdust
A
SINGLE STAGE SIMULTANEOUS SEPARATION AND PRE CONCENTRATION OF RARE
EARTH ELEMENTS ON ACTIVATED CARBON FOR ITS DETERMINATION BY ICP-OES
AFTER WET ASHING - APPLICATION TO SOIL SAMPLES
G.Chakrapani,
P.L.Mahanta, V.V.Hanuman and P.K.Srivastava
Atomic
Minerals Directorate for Exploration and Research
Department
of Atomic Energy, Central Region
AMD
Complex, Civil Lines, Nagpur - 440 001
Abstract
A
simple, rapid, cost effective simultaneous separation and pre concentration
method is developed for
determination of Rare earth elements in soil samples at sub ppm levels
by inductively coupled plasma-optical emission spectrometry (ICP-OES).
The method is based on sorption of REEs on powered activated carbon
(AC) in 2–3 M HF medium. The soil samples are decomposed by HF-HCl
treatment followed by fusion of residue with Na2CO3. Keeping in view
its application to soil samples, experimental parameters such as effect
of HF, amount of AC, contact time, sample weight were optimized for
quantitative sorption. The unique feature of the method is, REEs are
desorbed quantitatively from activated carbon, by completely oxidizing
and solubilizing AC by wet digestion (HNO3 – HClO4 treatment). Thus
the time consuming and tedious method of ignition of charcoal to ashes
is avoided, to increase the sample throughput in geochemical exploration
studies. The precision of the method is ± 7% at 1 ppm level.
The accuracy of the method is evaluated by analyzing soil standard
reference materials i.e. by using CANMET (Canada Center for Mineral
and Energy Technology) standards, such as SO-2, SO-3 and SO-4. The
composition of these soil standards closely match with the composition
of soil samples under investigation. The method is being applied on
numerous soil samples collected during geochemical exploration of uranium.
The REEs in soil samples are determined down to ppm and sub ppm levels,
based on separation of REEs from two gram soil sample making up to
final volume of 25 ml . The method could be adopted by any laboratory
as the input involved is inexpensive activated carbon associated with
minimal skill unlike the reported methods of ion exchange and solvent
extraction.
Key words : Rare earth elements, Soil, Pre concentration, Activated
Carbon, ICP-OES and Wet ashing
SIMULTANEOUS
SEPERATION OF RARE EARTH ELEMENTS FROM GEOLOGICAL SAMPLES BASED
ON PRECONCENTRATION ON ACTIVATED CARBON AND ITS DETERMINATION BY
ICP-OES
G.Chakrapani,
S.K.Jain and P.K.Srivastava
Atomic
Minerals Directorate for Exploration and Research
Department
of Atomic Energy, Central Region
AMD
Complex, Civil Lines, Nagpur - 440 001
Abstract
A
simple and cost effective preconcentration method is described for
the determination of Rare earth elements (REEs)
in geological samples (Barium rich) by ICP-AES. The method presented
is a single stage separation technique and involves simultaneous separation
of barium and preconcentration of REEs onto Activated Carbon (AC) from
barites. The REEs are selectively sorbed onto AC at pH 6 ± 1,
in presence of complexing agent, triethanolamine, used to prevent precipitation
by various interfering elements. The effects of various parameters
for quantitative sorption of REEs on AC are discussed. The REEs are
desorbed from AC simply by treating AC with 3.2 M HNO3, thus avoiding
the tedious and time consuming operation of ashing AC. The decontamination
factor for Ba is around 1600. The concentration of Ba in the final
preconcentrate (25 ml) is <10 ug/ml and its interference on REEs
by ICP-AES is negligible. An high enrichment factor for REEs is achievable
by taking large sample weight, to have a better precision. Accuracy
of the method is evaluated by comparing it with ion exchange method.
The precision of the method is ± 10 % at one ppm level. The
method has been applied on numerous barite samples for determination
of REEs.
DETERMINATION
OF RARE EARTH ELEMENTS AND YTTRIUM IN ROCK SAMPLES BY INDUCTIVELY
COUPLED PLASMA OPTICAL EMISSION SPECTROMETRY
Adarsh
Kumar, Beena Sunilkumar, R.Lalithambal and G.S.Chowdary
Chemistry
Laboratory,
Atomic
Minerals Directorate for Exploration and Research,
Department
of Atomic Energy
Northern
Region, New Delhi.
Abstract
Rare
earth elements and yttrium in rock samples were determined by ICP
-OES (Model JY2000- 2). As this
instrument is provided with 4320 grooves/mm grating, the results obtained
by direct determination without separation from the matrix elements
(1.0g/100ml) and those obtained after separation (1.0g / 25ml) are
compared. Rock samples that are enriched ~50 times with respect to
chondrite levels can be determined without separation. Some of the
inter rare-earth element interferences and quantum of interferences
are presented in this paper.
SEPARATION,
PRECONCENTRATION AND ESTIMATION OF RARE EARTH AND TRACE ELEMENTS
BY INDUCTIVELY COUPLED PLASMA ATOMIC EMISSION SPECTROMETRY (ICP
- AES) IN THORIUM MATRICES
Prithwish
Chakraborty1,
Vijay Kumar2, Smeer Durani3 and
K.Satyanarayana4
Chemistry
Laboratory,
Atomic
Minerals Directorate for Exploration and Research
Department
of Atomic Energy
1Shillong
- 793 011, 2Jaipur
– 302 030,
3Hyderabad
- 500 016 and 4Bangalore
- 560 072
Abstract
A simple, sensitive and efficient method is developed
for the separation of Rare earth elements (REEs) La-Lu, & Y and
some trace elements Cd, Co, Cr, Cu, Ni, V, Zn from thorium matrix and
their subsequent estimations by ICP-AES. In thorium-rich geological
samples, the estimation of REE’s by ICP-AES suffers from the spectral
interferences due to the presence of excess of Th. In the proposed
method, thorium is separated from the matrix by the solvent extraction.
To optimize the separation of REEs and trace elements from Th matrix,
synthetic mixture solutions was prepared containing Th, REEs and trace
elements maintaining different acidic conditions (1M, 2M, 4M, 6M, 8M & 10M
HNO3 and 2M, 4M, 6M & 8M HCl) and each solution was subjected
to solvent extraction. The solvent extraction was carried out using
a
mixture of di-2-ethylhexyl phosphoric acid (in 30 % Toluene) and
1- pentanol in the ratio of 5:1. The aqueous phase containing the
required
elements was evaporated to dryness and an acidity of 5% HCl is maintained
in final volume. Solutions were analysed by ICP-AES and the quantitative
recovery of REEs and Trace elements were obtained at 6M HNO3 acidity
condition. The developed method was applied to the certified standard
reference material; IGS-36 and the values obtained were comparable
with the certified values. The method was also applied to the real
time monazite samples and the recovery was quantitative. Corrections
have been applied for the REEs inter-elemental interferences in ICP-AES.
Key words: ICP-AES, REEs, Solvent extraction
ANION
EXCHANGE CHROMATOGRAPHIC SEPARATION AND DETERMINATION OF REEs AND
OTHER TRACE ELEMENTS IN Fe
-RICH SAMPLES BY ICP -AES
K.Satyanarayana,
B.Gomathyamma and B.K.Balaji
Chemistry
Laboratory, Southern Region,
Atomic
Minerals Directorate for Exploration and Research
AMD
Complex, Nagarbhavi, Bangalore.
Abstract
An
inductively Coupled Plasma Atomic Emission Spectrometric (ICP – AES)
method has been developed for determination
of rare earth elements (REEs), Y, Sc and other trace elements like
Ba, Be, Cr, Mn, Ni, Sr, Th and V in Fe – rich geological materials
after separation and preconcentration through anion exchange column
chormatography using Amberlite IRA-400 (Cl- form) in 6 M HCl solutions
and after decomposing the samples with HF – HCl acid mixture. The advantage
of this method is that the Fe3+ is completely retained
in the resin and the eluant contains all the above trace elements including
Y and
Sc. The eluant has been evaporated and taken in 25 ml volume at 5%
acidity with reference to HCl and this solution is used for the aspiration
in ICP – AES. The accuracy of the method is tested by various methods
of separation and determination of REE which include cation – exchange
separation, fluoride separation and solvent extraction methods and
also by analysing few Standard Reference Materials like FER – 1 to
4, SY - 2 and SY - 3. The approved values are in excellent agreement
with the reported values for other trace elements in FER – 1 to 4 and
for REE, Y and Sc in SY – 2 and SY – 3 after doping them with 250 mg
of Spec Pure Iron Matrix. This method is rapid, simple, accurate and
precise, with % RSD ranges from 2 – 5 %.
DEVELOPMENT
OF CLOUD POINT EXTRACTION - UV-VISIBLE SPECTROPHOTOMETRIC METHOD
FOR VANADIUM (V) DETERMINATION IN HYDROGEOCHEMICAL SAMPLES
Smeer
Durani1,
Neerja Mathur1 and G.S.Chowdary2
Chemistry
Laboratory, Atomic
Minerals Directorate for Exploration and Research
Department
of Atomic Energy
1Begumpet,
Hyderabad, 2West Block VII, R.K.Puram, New Delhi
Abstract
The cloud point
extraction behavior (CPE) of Vanadium (V) using 5,7 dibromo 8-hydroxyquinoline
(DBHQ) and Triton X 100 was investigated. Vanadium (V) was extracted
with 4 ml of 0.5 mg/ml DBHQ and 6 ml of 8% (V/V) Triton X 100 at the
pH 3.7. A few hydrogeochemical samples were analysed for vanadium using
the above method.
Key-words:
Spectro-photometry, Vanadium, DBHQ, Triton-X, Cloud point, Extraction
SPECTROPHOTOMETRIC
DETERMINATION OF FLUORIDE IN WATER
P.K.Tarafder
and R.K.Mondal
Chemistry
Laboratory, Atomic Minerals Directorate for Exploration and Research
Department
of Atomic Energy
Khasmahal
P.O. Tata Nagar, Jamshedpur
Abstract
Alizarin
Red-S, which is used routinely for the spectrophotometric determination
of aluminium in silicate rock
samples, has been successfully applied in the estimation of fluoride
at ppm levels in a number of hydrogeochemical samples. The reddish-orange
lake formed by the co-ordination of Al +3 ion with Alizarin
Red-S at a pH of 3.8 is inhibited in the presence of fluoride ion.
By this method,
fluoride can be estimated up to 10 ppm in hydrogeochemical and environmental
water samples. No other interference except Al+3 was encountered in
the estimation of fluoride in hydrogeochemical and environment samples
by this method. The results obtained have been found to be in good
agreement with those obtained by the standard method of fluoride determination.
DETERMINATION
OF PHOSPHATE IN WATER SAMPLES BY VANADO-MOLYBDATE METHOD IN PRESENCE
OF SILICA USING UV-VISIBLE SPECTROPHOTOMETER - A STUDY OF THE EFFECT
OF ACID CONCENTRATION
Satya
Prakash and Vijay Kumar
Chemistry
Laboratory, Western Region,
Atomic
Minerals Directorate for Exploration and Research
Studies
were carried out on the effect of acid concentration on the interference
of silica in the estimation
of phosphate in water samples by the vanado-molybdate method. It has
been observed that silica upto 500 µg/ml does not interfere in
the estimation of phosphate if the colour is developed at 1.4 to 1.5
N of HNO3 and hence absorbance measurements can be carried out directly
at that acidity without desiccating and filtering off silica.
2-THENOYL
TRIFLUOROACETONE (TTA) FUNCTIONALIZED AMBERLITE XAD-2: A NEWLY
DESIGNED CHELATING RESIN FOR ENRICHMENT OF Cu(II), Cd(II), Co(II),
Ni(II), Pb(II), Zn(II), Mn(II), Fe(III) FROM WATER PRIOR TO THEIR
DETERMINATION BY FLAME-AAS AND UO2(II)
BY FLUORIMETRY. A GREEN ANALYTICAL METHOD
Manjeet
Kumar
Chemistry
Laboratory,
Atomic
Minerals Directorate for Exploration and Research
Department
of Atomic Energy
West
Block - VII, R.K.Puram, New Delhi.
Abstract
Amberlite XAD–2 has been functionalized
by coupling it through an –N=N– group with TTA. The resulting chelating
resin, characterised by elemental analyses, TGA and IR spectra, has
been used to preconcentrate trace metals from water samples prior
to their determination by flame–AAS or fluorimetry. The pH ranges
for quantitative sorption, recovery studies, sorption capacity of
the resin, loading half time (t1/2) and effect of electrolytes on
the sorption of these metal ions have been studied. The enrichment
factor and the lower limits of detection for Cu, Cd, Co, Ni, Pb,
Zn, Mn, Fe and uranyl ion has been found to be 200, 70, 64, 80, 40,
180, 80, 72 and 125; and 1.43, 1.75, 3.93, 5.15, 18.14, 0.46, 1.5,
5.53 and 0.74 mg L–1, respectively.
Key-words: Chelating resin, Amberlite, Limits of detection, Sorption,
DETERMINATION
OF ANIONS IN HYDROGEOCHEMICAL SAMPLES FOR URANIUM EXPLORATION
USING ION CHROMATOGRAPHY
A.Thangaraj,
Vijay Kumar and P.N.Bangroo
Chemistry
Laboratory, Western Region,
Atomic
Minerals Directorate for Exploration and Research
Department
of Atomic Energy, AMD Complex,
Sector
V Extension, Pratap Nagar, Sanganer, Jaipur
Abstract
The potential of Ion Chromatography
for the estimation of anions has been utilized /applied in the determination
of various anions present in water samples generated during the hydrogeochemical
survey for the exploration of Uranium. Various combinations of eluent
concentrations were tried out and the most suitable concentration
was applied for proper separation of the anions. The method was applied
in the estimation of various anions including among others fluoride,
nitrite, nitrate and bromide in water samples received in the laboratory.
PERFORMANCE
VERIFICATION OF UV-VIS SPECTROPHOTOMETERS USING SIMPLE DIAGNOSTIC
TESTS
Smeer
Durani, A.V.Raghunadh, K.Subramanyam and D.S.R.Murty
Chemistry
Laboratory,
Atomic
Minerals Directorate for Exploration and Research
Department
of Atomic Energy
Begumpet,
Hyderabad
Abstract
UV-VIS Spectrophotometers have
been used as a tool for chemical analysis for many years. These instruments
are reliable and convenient to use and therefore, they find important
application in many fields. In the present case, the performance
evaluation of UV-VIS Spectrophotometer, Shimadzu Model UV-2100 was
checked for wavelength accuracy, stray light, resolution, noise,
baseline flatness, photometric accuracy and photometric reproducibility.
The performance evaluation carried out, suggests that deviations
are within permissible limits.
Atomic
Minerals Directorate for Exploration and Research
Department
of Atomic Energy
Northern
Region, New Delhi.
Abstract
Some of the simple diagnostic
tests like intensity ratio of atomic and ionic lines of magnesium,
monochromator resolution, resolution of doublets and triplets and
detection limits were carried out in our laboratory and results obtained
are presented.
CHARACTERISATION
OF THE ANALYTICAL PERFORMANCE OF ICP-MS BY SIMPLE DIAGNOSTIC
TESTS
V.Padmasubashini,
Leela Gopal, A.K.Singh and D.S.R.Murty
Chemistry
Laboratory,
Atomic
Minerals Directorate for Exploration and Research
Department
of Atomic Energy
Begumpet,
Hyderabad
Abstract
A Micromass Platform ICP-MS
was installed in our laboratory last year. As the first step, the
analytical performance of the newly installed ICP-MS was assessed
by carrying out various simple diagnostic tests to ascertain whether
the instrument fulfilled the various specifications quoted by its
manufacturers. These tests helped in the optimization of various
instrumental parameters of ICP-MS in order to get accurate and
precise analytical results. The details and results of the diagnostic
tests are presented in this paper. These tests also contributed
towards acquiring a better understanding of the working of the
instrument and the principles underlying its operation and maintenance.
TRENDS
IN THE METHODS OF MEASUREMENT IN ANALYTICAL CHEMISTRY
D.P.S.Rathore
Chemistry
Laboratory, Western Region,
Atomic
Minerals Directorate for Exploration and Research
Department
of Atomic Energy
Jaipur
Abstract
In
this paper, the trends in the methods of measurement in an instrumental
technique for analytical
chemical measurement is presented. There are three methods of measurement
in analytical chemistry, namely (i) calibration method, (ii) standard
addition method and (iii) differential technique. Calibration method
is the most commonly used for testing the linearity of the response
of the instruments in the concentration range of the analyte adhering
to Beer’s law. In the Standard addition (Internal standards) method,
the addition of known amount of analyte to a sample and the observation
of the response from that standard provides an easy method of accounting
for any interferences in the sample. Standard additions method
is generally recommended to test the validity of a new analytical
method and also to account for any matrix effect. Differential
technique (DT) is based on the comparison of the signal response
of the accurately known standards with a sample of similar but
unknown concentration on same sample weight or dilution basis.
Differential technique using reference standards guarantees the
quality of an analytical result (accuracy, high precision, reliability,
comparability & traceability). It is a self-standardized and
an absolute methodology of measurement .
Key-words:
measurements, calibration, standard addition, differential technique,
instrumental technique.
NICKEL
SULFIDE AND LEAD FIRE ASSAY TECHNIQUES IN THE DETERMINATION
OF GOLD AND PLATINUM GROUP ELEMENTS (PGEs) IN GEOLOGICAL SAMPLES
S.Nandakishore,
A.V.Raghunadh and D.S.R.Murty
Chemistry
Laboratory,
Atomic
Minerals Directorate for Exploration and Research
Begumpet,
Hyderabad
Abstract
It
was for the first time in AMD, chemical laboratory, the Nickel
Sulfide and Lead fire assay techniques were introduced for the
determination of gold and Platinum Group Elements(PGE), in geological
samples. The paper discusses about maiden experiences, working
with high temperature fusions in big furnaces with large amount
of the fluxes and samples to over come the problems of nugget
effect and low abundance of precious metals and to break complex
matrix, in which these elements are present in nature. It also
discusses the problems faced during the dissolution of the Ag
prill, and measurement by ICPMS and AAS. The safety precautions
to be taken while working with this technique, which is skill
based and labour intensive are also enumerated in this paper.
Since, the fire assay was started very recently, we are presenting
only initial results with only three standard reference materials
SARM-7, SARM-53 and MA-1b which were used for standardizing the
procedures.
Key words: Nickel Sulfide Fire assay, Lead fire assay, Silver prill
.
DITHIZONE
SUPPORTED NAPHTHALENE - A NOVEL ADSORBENT FOR GOLD, PALLADIUM
AND SILVER
Anitha
Mary Thomas and
*D.S.R.Murty
Atomic
Minerals Directorate for Exploration and Research
Department
of Atomic Energy
Nagarbhavi,
Bangalore, *Begumpet, Hyderabad
Abstract
A simple, precise adsorption
method is developed for separation/ preconcentration of gold, palladium
and silver on microcrystalline naphthalene as a solid support for
dithizone. Metals are collected on the adsorbent at pH 1 in nitric
acid medium. Adsorbed elements are recovered by removing naphthalene
by sublimation and destructing dithizone with HNO3/HClO4 treatment.
The method is applied in the determination of gold and silver in
various geological sample matrices. Accuracy is tested by analysing
certified reference materials.
Key words: preconcentration, dithiozone, naphthalene, PG elements
DETERMINATION
OF SILVER IN SULFIDE BEARING ROCK SAMPLES
R.Lalithambal,
J.C.Sachdev, G.S.Chowdary and Adarsh Kumar
Chemistry
Laboratory,
Atomic
Minerals Directorate for Exploration and Research
Department
of Atomic Energy
Northern
Region, New Delhi
Abstract
Silver was determined in sulfide
bearing rock samples by flame atomic absorption spectrometry after
a simple treatment of the samples with nitric acid. Graphite furnace
was used for samples which contained less than 0.5 parts per million
of silver. Inductively coupled plasma optical emission spectrometry
was used to confirm values that are greater than one part per million
and ensure that no silver remained in the silicate matrix after complete
dissolution of the sample by hydrofluoric acid and nitric acid treatment.
DETERMINATION
OF THORIUM IN GEOLOGICAL MATERIALS BY ICP-OES AFTER SEPARATION
USING ACTIVATED CHARCOAL
Beena
Sunilkumar,
G.S.Chowdary and Adarsh Kumar
Chemistry
Laboratory, Northern Region,
Atomic
Minerals Directorate for Exploration and Research
Department
of Atomic Energy, New Delhi
Abstract
The procedure reported in literature
for determination of Thorium in geological samples involves the well
known method for separation of Thorium as fluoride precipitate and
subsequent estimation of Th by ICP OES or spectrophotometry using
Arsenazo III as a chromogenic reagent. In this paper a method has
been standardized for the estimation of Th by ICP OES after separating
Th using activated charcoal. The present method is very sensitive,
precise, simple and economical. The major advantage of this method
is that rare-earth elements can be estimated along with thorium in
the same solution. When thorium present is greater than 50 ppm, it
can be directly determined without separation from the matrix elements.
Th II 401.913 nm analytical line was used for the determination by
ICP- OES.
Key-words:
ICP-OES, Thorium, Geological samples, Arsenazo III, Spectrophotometry.
DETERMINATION
OF Th AND REE IN COLUMBITE - TANTALITE SAMPLES BY ICP-OES
V.V.Hanuman,
C.R.Khorge, R.Radhamani, Sajitha Nair and P.K.Srivastava
Chemical
Laboratory, Central Region,
Atomic
Minerals Directorate for Exploration and Research
AMD
Complex, Civil Lines, Nagpur
Abstract
A simple method of decomposition
and separation of Th and REE in columbite- tantalite is developed
for determination by ICP- OES. The sample is decomposed with hydrofluoric
and hydrochloric acid in presence of little sulphuric acid to avoid
drying on water bath. Th and rare earth is separated as fluoride
together with un decomposed sample. The residue is fused with a 1:
1 mixture of sodium di hydrogen orthophosphate and sodium pyrophosphate.
The melt is dissolved in water for measurement. Nitric acid is found
unsuitable due to loss in Ce in some of the samples. Matrix elements
(more than 97.5) are removed in single step by both the treatment.
The free cassiterite present in samples is not attacked during acid
digestion. However, the same is easily decomposed in fusion. U (IV)
is also precipitated along with Th and REE when hydrochloric acid
is used. As expected Uranium is lost when nitric acid is used. The
results are compared with existing well-established procedure involving
peroxide fusion for decomposition; hydroxide and fluoride precipitation
separation. Both the method yielded comparable result. The method
is simple, comparatively rapid and very much suitable for routine
application for determination of REE , Th and U(IV) content. The
RSD of the method was found to be in the range of 1- 1.5% for various
elements.
RAPID
DECOMPOSITION OF MONAZITE AND XENOTIME FOR DETERMINATION OF Th
AND REE BY INDUCTIVELY COUPLED PLASMA EMISSION SPECTROMETRY
R.Radhamani,
P.Murugesan and P.K.Srivastava
Chemical
Laboratory, Central Region,
Atomic
Minerals Directorate for Exploration and Research
AMD
Complex, Civil Lines, Nagpur 440001
Abstract
A rapid method of decomposition
and dissolution of REE phosphate minerals is developed for the determination
of Th and REE by inductively coupled plasma optical emission spectrometry.
Sample is decomposed by fusion with 1: 1 mixture of sodium di-hydrogen
phosphate and sodium pyrophosphate in a platinum crucible. Unlike
Ti and Nb –Ta minerals the melt cannot be dissolved in water. Ce
polyphosphate precipitates, which is soluble in dilute hydrochloric
acid. The solution is diluted to desired volume before measurement
by ICP-OES. The results are computed from the calibration standard
containing same quantity of hydrochloric acid and polyphosphate.
The results are compared with the results obtained by established
procedure involving sulphuric acid decomposition. Comparable results
are obtained. The validity of the method is checked by analysing
standard reference material. The method is simple, comparatively
less time consuming eco-friendly and very much suitable for routine
analysis of REE concentrate. The RSD of the procedure varies in the
range of 0.5 to 1.5% from element to element.
Keywords : Monazite, Xenotime, Decomposition with phosphate flux. ICP OES
DETERMINATION
OF ZIRCONIUM AND HAFNIUM IN GEOLOGICAL MATERIALS BY ICP-AES AFTER
PRE-CONCENTRATION ON ACTIVATED CARBON
V.Padmasubashini
and D.S.R.Murty
Chemistry
Laboratory,
Atomic
Minerals Directorate for Exploration and Research
Department
of Atomic Energy,
Begumpet,
Hyderabad.
Abstract
Systematic investigations have
been carried out on the adsorption of Zr and Hf on activated carbon
and on the influence of various experimental parameters like pH,
amount of carbon, contact time and volume of sample solution. The
efficiency of different acids for the desorption of Zr and Hf from
activated carbon have also been studied. Investigations on the interference
behaviour of various anions and cations commonly encountered in geological
materials as well as complexants routinely used in analysis, on the
adsorption of Zr and Hf have also been carried out. A simple and
efficient procedure for the estimation of Zr and Hf in geological
samples by ICP-AES after pre-concentration/separation by adsorption
on activated carbon has been developed. The validity of the method
has been verified by applying it to some standard reference materials
and values obtained are in good agreement with the certified values.
The method has also been applied to the determination of Zr in some
geological samples.
SOLVENT
EXTRACTION OF ZIRCONIUM(IV) AND HAFNIUM(IV) WITH THE NEUTRAL
LIGAND 1-PHENYL -2,3 DIMETHYL -5-PYRAZOLONE
IN PRESENCE OF PERCLORATE AS THE ANION
Roopa
Bose, D.S.R.Murty1, K.Satyanarayana
Chemistry
Laboratory,
Atomic
Minerals Directorate for Exploration and Research
Department
of Atomic Energy,
Nagarbhavi,
Bangalore, 1Begumpet, Hyderabad.
Abstract
A liquid liquid extraction study
of zirconium and hafnium in association with anion perchlorate and
the neutral ligand,1-phenyl-2,3,dimethyl–5-pyrazolone into the best
suited solvent has been studied in detail. The parameters influencing
the percent extraction of Zr(IV) and Hf(IV), such as various solvents,
equilibration time, reagent concentration, concentration of the metal
ions and presence of diverse ions have been studied in detail. The
stoichiometry of the extracted species obtained by the slope ratio
method indicate that the composition of the extractable complexes
of Zr(IV) and Hf(IV) are ZrO(Apy)2(ClO4)2 and HfO(Apy)2(ClO4)2 respectively.
The equilibrium constants of the quantitatively extractable complexes
have also been established. Based on the distribution data, Zr(IV)
could be successfully separated from it's binary mixture with uranium
.
A
NEW SAMPLE SOLUTION PREPARATION METHOD FOR COLUMBITE - TANTALITE
MINERALS USING LITHIUM METABORATE FUSION: ICP-AES DETERMINATION
OF Nb, Ta, Ti, Fe, Mn, Zr, W, Sn, Al, Si, Ca, Mg, Na, K, REE,
Y AND U
A.Premadas1
and P.Murugesan2
Chemistry
Laboratory,
Atomic
Minerals Directorate for Exploration and Research
A complete sample decomposition
and solution preparation procedure for the columbite and tantalite
minerals using lithium meta-borate fusion suitable for the ICP-AES
determination of major, minor and certain trace elements is described.
The sample solution of the fused mass is prepared in either sulphuric
acid-oxalic acid or hydrochloric acid-oxalic acid medium and the
solution is stable up to at least one month period of time studied.
After suitable dilution Nb, Ta, Ti, Fe, Mn, Zr, W, Sn, Al, Si, Ca
and Mg are determined directly by ICP-AES, the REE and Y are determined
after the cation exchange separation. The Na and K are determined
by FASS and U is determined by the fluorimetric method. The advantages
of the present method are compared with the reported methods. The
accuracy of the method is checked by analyzing certain standard reference
materials like IGS-33 (columbite) and IGS-34 (tantalite) for Nb,
Ta and Ti, and also by applying the present method on synthetic columbite-tantalite
type samples. The method is simple, rapid, accurate and reproducible.
SPECTROPHOTOMETRIC
DETERMINATION OF Nb AND Ta IN COLUMBITE - TANTALITE AND TIN
SLAG
P.L.Mahanta,
Amitabha Ray and P.K.Srivastava
Chemical
Laboratory, Central Region,
Atomic
Minerals Directorate for Exploration and Research
Civil Lines,
Nagpur.
Abstract
A
simple, effective and accurate method of decomposition, dissolution
and separation for the spectro-photometric
determination of Nb and Ta in Cb-Ta and Tin slag samples is described.
Cb-Ta samples are fused with (1:1) mixture of Sodium di-hydrogen
ortho-Phosphate and Tetra Sodium Pyrophosphate in a Pt crucible.
The melt is dissolved in distilled water. Tin slag samples are
treated with HF+ HNO3 to remove Si and then evaporated with HNO3 and fumed with H2SO4 to remove HF & HNO3 completely. Acid hydrolysis
was carried out in presence of SO2 solution. Nb and Ta are precipitated
quantitatively from HCL solution. The precipitate is filtered,
dried and again fused with the same flux and dissolved in distilled
water to get a clear solution. Suitable aliquots are taken for
the analysis of Nb by H2O2 and Ta by malachite green method. Iron
interferes in the analysis of Nb by H2O2 method so the optimum
parameters for quantitative Precipitation of Nb and Ta and complete
removal of Fe like volume of sample solution, HCl concentration
and effect of SO2 water are investigated.
The validity of the method is checked with CRMs IGS-33, IGS-34
and synthetic mixtures of varied composition conforming to Cb-Ta
and Sn slag. For tin slag samples validity of results were checked
by comparing with ICP AES analysis without separation. The RSD
of the method varies between 1-5% depending on concentration
Atomic
Minerals Directorate for Exploration and Research
Department
of Atomic Energy,
New
Delhi.
Abstract
A
method is described for the determination of arsenic in geological
materials by Inductively
Coupled Plasma Optical Emission Spectrometry (ICP OES). Arsenic
is separated from the major matrix elements by solvent (chloroform)
extraction of Arsenic (V)-Ammonium Pyrrolidine Dithiocarbomate
(APDC) complex. The method was validated by analyzing standard
reference materials. Arsenic at 1 µg/g level and above can
be determined.
ULTRA-TRACE
DETERMINATION OF MANGANESE BY DIRECT AND EXTRACTIVE FURNACE
ATOMIC ABSORPTION SPECTROPHOTOMETRY(GFAAS)
P.K.Tarafder
and S.K.Pradhan
Chemistry
Laboratory,
Atomic
Minerals Directorate for Exploration and Research
Department
of Atomic Energy,
Khasmahal
P.O., Tatanagar, Jamshedpur
Abstract
Two methods, direct as well
as extractive Graphite Furnace Atomic Absorption Spectrophotometric
(GFAAS) methods have been developed for the ultra-trace determination
of manganese in hydrogeochemical and silicate rock samples. Manganese,
irrespective of its valance state, was extracted as an ion pair
of Mn-Naphthalene-2,3-diol anionic chelate and CTA+ into ethyl
acetate in the pH range 10 to 12. Nanogram (ng) levels of manganese
has been successfully separated from the complex matrices of silicate
rocks and hydrogeochemical samples by using liquid-liquid extraction
of manganese in the form of above mentioned ion associate complex.
The recovery of manganese has been found to be more than 99.99%.
By applying the method, manganese in a number of hydrogeochemical
samples, including tap water as well as silicate rock samples has
been successfully determined with high degree of accuracy and precision
using GFAAS. The results obtained for manganese estimation in these
samples compare favorably with those obtained by flame-AAS. The
present paper describes the systematic studies on the optimization
of extraction parameters and GFAAS parameters for the analysis
of hydrogeochemical and silicate rock samples for the determination
of manganese.
Key-words: GFAAS, Manganese, Water samples, Hydrogeochemical.
SPECTROPHOTOMETRIC
DETERMINATION OF MOLYBDENUM IN CONCENTRATES
P.K.Tarafder,
Raghbendra Thakur and R.K.Mondal
Chemistry
Laboratory,
Atomic
Minerals Directorate for Exploration and Research
Department
of Atomic Energy,
Khasmahal
P.O., Tatanagar, Jamshedpur
Abstract
A
new method for the rapid and accurate estimation of molybdenum
in concentrates has been developed.
Mo(VI) reacts with the reagent, 2,3-dihydroxynaphthalene at pH-10
to 12 to yield a yellowish-orange chelate with lmax at 400 nm .The
molar absorptivity and Sandell’s Sensitivity of the method are
1.0x104 l.mol-1cm-1 and 0.0095 mg cm-2 respectively. The standard
deviation (s) and relative standard deviation (RSD) of 1mg/L Mo
for 5 replicate analyses are ±0.015 mg/L and 1.65 % respectively.
The method has been applied to a set of 5 different samples of
molybdenum concentrates received from UCIL, Jaduguda and results
obtained have been found to compare favourably with those obtained
by 8-hydroxyquinoline gravimetry.
DETERMINATION
OF CALCIUM AND MAGNESIUM IN GEOLOGICAL MATERIALS CONTAINING
HIGH SILICA, PHOSPHATE
AND IRON BY ION CHROMATOGRAPHY
Vijay
Kumar, A.Thangaraj, M.K.Ganguly and P.N.Bangroo
Chemistry
Laboratory, Western Region,
Atomic
Minerals Directorate for Exploration and Research
Department
of Atomic Energy,
AMD
Complex, Sector V Extension, Pratap Nagar, Sanganer, Jaipur
Abstract
A
method has been described for the determination of calcium and
magnesium in high silica,
phosphate and iron matrices by Ion chromatography, using Metrohm
Nucleosil 5SA separating column. 20 µL of sample solution
(<0.1% acidity) was injected for the estimation of calcium and
magnesium at ppm to percentage level in the samples containing
high silica, phosphate and iron. A mixture of 3.5 mM oxalic acid,2.5
mM ethylenediamine, and 5% acetone was used as the eluent at flow
rate 1.5ml/min for separating Ca and Mg species individually as
distinct chromatograms at different time intervals(5-10minutes).
Measuring the conductivity of Ca and Mg by 819 IC conductivity
meter and comparing the peak area with known standard calibrations
made the quantification. Validity of the method was ascertained
by standard additions and accuracy achieved was ± 5% at
the 10ppm level.
Key:words: Ion chromatography, silica, phosphate, calcium, magnesium,
eluents.
RAPID
DECOMPOSITION AND SPECTROPHOTOMETRIC DETERMINATION OF CHROMIUM
AND IRON IN CHROMATES
Sajitha
Nair and P.K.Srivastava
Atomic
Minerals Directorate for Exploration and Research
Central
Region, Nagpur-440001
Abstract
A new method is described for
decomposition, dissolution and spectrophotometric determination
of Cr and Fe in refractory chromite mineral using polyphosphate
complexes. The sample is decomposed with a mixture of sodium dihydrogen
phosphate and sodium pyrophosphate. The polyphosphate formed during
fusion keeps all the constituents in solution. Fe and Cr are measured
after appropriate dilutions of the sample solution at wavelengths
276 nm and 622 nm respectively. The solution is also suitable for
the measurement of major elements such as Cr, Fe, Al and Mg by
AAS [N2O - acetylene flame] and ICP- OES. The results are comparable.
Minor quantity of SiO2 [present as combined silica] also remains
in solution and is determined by ICP-OES. The result of one of
the samples [SiO2~16%] is checked gravimetrically and is comparable
to ICP-OES results. The method is applied to natural samples from
Sukinda chromite mine, Orissa. The method is simple, rapid and
easily adaptable for routine analysis of chromite ore. The RSD
of the spectrophotometric determination is ~ 1%
ISOTOPE
DILUTION AND ION EXCHANGE CHROMATOGRAPHY IN GEOCHRONOLOGICAL
STUDIES USING THERMAL IONISATION MASS SPECTROMETER (TIMS):
AN APPRAISAL
D.V.L.N.Sastry,
Girija Srinivasan and S.Nayak
Geochronology
Laboratory,
AMD,
Begumpet, Hyderabad - 16
Abstract
Rb-Sr, Sm-Nd and U/Pb-Pb geochronology
using Thermal Ionisation Mass Spectrometer (TIMS) coupled with
isotope dilution techniques warrants optimum separation of the
desired elements from the geological samples in as pure a form
as possible so that the isobaric interferences which are very common
in mass spectrometers, are avoided and a steady ion beam is produced
in the mass spectrometer thereby facilitating in the most precise
and accurate measurements of elemental abundances and isotopic
ratios.
Ion exchange chromatography using analytical grade resins viz.
AG 50W X 12 for Rb, Sr and REE group, HDEHP coated Bio-bead S x8
for Sm and Nd and AG 1 X 8 for U and Pb, play a significant role
in the separation of the above elements using HCl, HNO3 and
HBr of different normalities as the eluants.
Key words : Thermal Ionisation Mass Spectrometer(TIMS), Isotope
Dilution Mass Spectrometry(IDMS), Ion Exchange Chromatography(IEC),
HDEHP coated Bio Beads
