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Recent Advances in ICP-MS and ICP-OES Technology for the Determination of Heavy Metals and Trace Elements in Contaminated Soil Samples September 28, 2011 1 Raimund Wahlen ICP-MS Product Specialist Agilent Technologies 2 nd SCLF Conference, 8 th September 2011 Strathclyde University, Glasgow
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Recent Advances in ICP-MS and ICP-OES Technology fo r the Determination of Heavy Metals and Trace Element s in

Contaminated Soil Samples

September 28, 20111

Raimund WahlenICP-MS Product Specialist

Agilent Technologies

2nd SCLF Conference, 8th September 2011Strathclyde University, Glasgow

VarianICP-OES/AA experts.

AgilentICP-MS experts.

Environmental, Semiconductor market leadership.

CLEARLY BETTERAtomic Spectroscopy

ICP-OES/AA experts.Geo/Mineral, Industrial

market leadership.

INSTRUMENTS and SERVICES TO SUIT YOUR NEEDSFROM ONE VENDOR, IN ALL KEY APPLICATION SEGMENTS INCLUDING YOURS

=

Overview

• Introduction

• Benefits of the Agilent 700 Series ICP-OES system

• Limitations of ‘conventional’ ICP-MS systems for high-matrix samples

• Advances in ICP-MS technology to address limitations• Advances in ICP-MS technology to address limitations

• Case studies using the 7700x ICP-MS

1) Direct analysis of concentrated waste-water samples

2) Analysis of river sediments from an abandoned mine site (Dylife Mine, Wales)

• Conclusions

September 28, 2011Confidentiality Label

3

Introduction• Analysts have a variety of techniques at their disposal for elemental analysisin contaminated land samples. Choice depends on analytical requirements:

• AAS

• ICP-OES

• ICP-MS

• Others – Hg analysers, AFS, CV etc

• Commercial contract laboratories for trace analysis operate in a very competitive

September 28, 20114

market and constantly seek to improve productivity and reduce costs of operation

• Challenges presented by the sample types (soils, sediments, sludges, waste waters,groundwaters, etc) to be analysed include:

• Variable concentrations of matrix components + analyte levels (ppt – ppm/% levels)

• Samples always require pre-treatment (e.g. acid digestion) – sometimes different preps for differenttechniques above

• Operating/ running + servicing costs for multi-technique approach are relatively high and turnaroundtime is slow

Benefits of the Agilent 700 Series OES

Full wavelength coverage• Highest dynamic range with use of MultiCal• Use of qualifier wavelength to check for spectral interference

Fully simultaneous: all wavelengths, all intensities• Highest speed and best productivity• Best precision and accuracy

Few optical components

5

Few optical components• High light throughput• Best signal/noise ratio• Lowest detection limits

Thermostated spectrometer without mechanical movement

• Best stability• Short warm up time

One View / One Step

The axial ICP-OES with CCI from Agilent offers best detection limits with accurate determination of alkaline- and earth alkaline elements at the same time. Together with short warm up time this results in best productivity and lowest running costs

6

One View / Two Steps

Agilent 710 and 720 ICP-OES have a horizintal torch like dual

view systems. Instead of viewing through a hole on the side of the

torch, Agilent Dual shot uses software controled extra robust

conditions for a second shot from the front. the front.

With this conditions potassium is not influenced by matrix changes without using ionisation buffer.

7

Stability fast sample measurement 720-ES %RSD of 19 elements at mean value 0.33%

240 samples with Agilent 720 ICP-OES (195 min)

1.01

1.02

1.03

1.04

mg/

l

0.96

0.97

0.98

0.99

1

1 26 51 76 101 126 151 176 201 226

Anzahl Proben

mg/

l

As 193.696 MW As Cu 327.395 MW Cu Pb 220.353 MW Pb Sb 206.834 MW Sb

Soil analysis with microwave digestion (6 individual digestions)

• Good recovery down to 0.28 mg/kg Cd

Light sandy soil CRM 7002 with Agilent 725-ES

mean (n=6)mg/kg

StdDevmg/kg

Cert.mg/kg

Unc.mg/kg % Rec.

As 188.980 26.4 0.55 26.1 1.1 101.1

Ba 233.527 100.0 3.10 99.1 - 100.9

Cd 228.802 0.28 0.02 0.28 0.03 99.2

Co 228.615 11.5 0.28 11.1 0.5 103.9

Cr 267.716 148 3 147 8 100.4

Cu 327.395 27.7 2.28 27.3 0.7 101.4

Mn 293.931 527 13 531 19 99.2

Ni 231.604 39.9 1.01 40.1 1.2 99.5

Pb 220.353 35.5 1.29 35.5 0.9 100.1

V 311.837 44.0 0.97 44.6 3.4 98.7

Zn 206.200 63.9 1.91 64.0 1.5 99.8

Limitations of ‘conventional’ ICP -MS systems for high -matrix analysis• Limited tolerance to Total Dissolved Solids (TDS typically <0.1 – 0.2%

max)

• Either long-term stability is compromised or

• Frequent recalibrations are required or

• Samples have to be diluted significantly prior to analysis

• Further drawback is increased maintenance (interface, ion lenses)

• Formation of matrix-based polyatomic ions create interferences on main • Formation of matrix-based polyatomic ions create interferences on main analyte isotopes (e.g. 23Na40Ar+ on 63Cu+, 40Ar35Cl+ + 40Ca35Cl+ on 75As+)

• Choice of target isotope requires prior knowledge of matrix

• Minor isotope has to be used – resulting in poorer LODs

• Multiple simultaneous interferences can interfere with all analyte isotopes

• Mathematical correction equations increase analysis time (and may still result in biased data)

• Choice of reagents (e.g. acids) often limited to reduce polyatomics – can lead to stability problems for Ag, Hg, Sb, Mo, etc

• Poorer productivity + greater likelyhood of bias in results

September 28, 201110

How can we improve the analysis of variable high -matrix samples with the 7700x? High matrix introduction

(HMI) dilution gas inlet

3rd generation Octopole Reaction

System (ORS3) for enhanced He

mode performance

• Unique gas dilution of sample aerosol significantly improves plasma robustness (CeO/Ce ratio < 0.3%)• This significantly enhances the TDS tolerance of the ICP (up to % level)

Benefits are:1. No liquid dilution of high TDS

• He collision mode uniquely capable of removing multiple, simultaneous polyatomic interferences in complex, variable matrices• Lower detection limits for greater variety of interfered isotopes including 28Si, 34S, 31P, as well as ‘usual suspects’ e.g. 75As, 52Cr, 63Cu etc.

September 28, 201111

1. No liquid dilution of high TDS matrices required

a) Increased productivityb) Dilution errors eliminatedc) Less risk of contamination

2. Matrix matching of standards less critical

3. Matrix deposits significantly reduced � less maintenance/ downtime

4. Eliminates need for frequent re-calibrations to account for matrix related drift

Benefits are:1. Simple instrument setup/ configuration

a) Only He neededb) Less method development for cell

settingsc) Only one tune mode neededd) No gas switching time

2. No need for correction equations for polyatomics

a) Reduces no. of isotopes + analysis time

b) Reduces potential bias due to over/ under correction

What is HMI/ aerosol dilution?HMI is a sample dilution technique but, uniquely, it dilutes the sample in the gas state,

using aerosol dilution.

This removes the main problems of liquid sample dilution:

• Time

• Reagents

• Errors

• Contamination

September 28, 201112

Case Study 1 – Waste water analysis• Major European contract laboratory (Eurofins Analytico, NL) seeking to optimise productivity andreduce running costs by using a simple 2-step approach for waste-water analysis:

1. Microwave digestion with aqua-regia according to Dutch regulation AS3000 followed by

2. Direct analysis with ICP-MS for all target analytes (>30 elements including Be, P, S, Ti, V, Cr, As, Se,Cd and Hg)

• Challenges of this approach:

1. Digested samples have high concentrations of total dissolved solids (TDS) >0.2%, exceeding TDStolerance of conventional ICP-MS

� Plasma needs to be able to tolerate high TDS to avoid excessive build-up of matrix on interface and resulting signaldrift

September 28, 201113

drift

2. Samples contain high levels of acids (12% HCl/ 4%HNO3 (v/v))

a. High acid concentration can degrade cone material rapidly

b. High Cl levels in acid result in Cl-based polyatomic species

� ICP-MS needs to be capable of handling high acid solutions and have efficient way of removing Cl-basedpolyatomics.

• An Agilent 7700x ICP-MS was chosen for this work due to the high sensitivity specification,excellent matrix tolerance provided by aerosol dilution (HMI) and the capabilities of the thirdgeneration octopole collision cell optimised for He mode

Sample preparation• Digestions for wastewater samples were performed with a CEM Mars microwave with a 40 position carousel

Sample (25mL waste water)

6 mL conc HCl + 2mL concHNO3

MW digestion:

• The final digest solutions containing 12% HCl / 4% HNO3 (v/v) were directly analyzed on an Agilent 7700x ICP-MS incorporating High-Matrix Introduction capability.

September 28, 201114

MW digestion:

0°C to 155°C in 30 min.

Hold at 155°C for 25 min.

Cooling cycle

Transfer to sample tube and make to 50mL with UP H2O

ICP-MS conditionsICP-MS Agilent 7700x

Nebulizer Burgener MiraMist

RF Power 1600 W

Sampling Depth 10.0 mm

Carrier gas 0.6 L/min

HMI dilution gas 0.4 L/min

KED voltage 3V

He flow rate 4.3 mL/min

Calibration ranges:0 – 2 µg/L Hg0 – 250 µg/L Ag

September 28, 201115

0 – 250 µg/L Ag0 – 500 µg/L Li, Be, Ti, V, Cr,

Mn, Ni, Co, Cu, Zn, As,Se, Sr, Mo, Cd, Sn,Sb, Te, Ba, Ce, Tl, Pb

0 – 1 mg/L Zr, W0 – 2.5 mg/L B0 – 10 mg/L Br, In0 – 50 mg/L Na, Fe, K, Ca, Al, Mg0 – 100 mg/L P, S0 – 1000 mg/L C

Results – MDLs, Spike recoveries

Low level spike High level spike

Analyte Unit MDL (3σ)MDL

requiredSpike added

Recovery %

Spike addedRecovery

%9Be [ ug/l ] 0.80 1 10 108.6 1000 95.411B [ ug/l ] 25.6 60 500 95.8 10000 104.6

23Na [ mg/l ] 0.12 0.2 1 108.8 20 104.624Mg [ mg/l ] 0.03 0.1 1 102.3 20 96.3

27Al [ mg/l ] 0.05 0.1 1 105.3 20 104.331P [ mg/l ] 0.03 0.05 0.4 102.7 20 95.034S [ mg/l ] 0.83 1 5 102.9 100 100.239K [ mg/l ] 0.18 0.2 1 102.5 20 100.6

44Ca [ mg/l ] 0.22 0.2 1.5 132.2 20 118.947Ti [ ug/l ] 9.10 20 150 103.5 1000 100.451V [ ug/l ] 2.80 10 100 103.7 1000 101.4

52Cr [ ug/l ] 1.89 5 40 104.8 1000 98.355Mn [ ug/l ] 0.004 0.02 0.15 101.8 1 101.456Fe [ ug/l ] 0.03 0.05 0.5 102.0 20 99.659Co [ ug/l ] 2.01 10 100 100.3 1000 99.7

All data ‘pooled from 10 different analysis days over a 30-day validation period

Main isotopes used without need for mathematical interference correction

September 28, 201116

Co [ ug/l ] 2.01 10 100 100.3 1000 99.760Ni [ ug/l ] 1.99 5 40 102.2 1000 96.2

63Cu [ ug/l ] 1.03 5 40 99.8 1000 97.866Zn [ ug/l ] 6.03 10 100 98.6 1000 98.175As [ ug/l ] 1.22 2 15 100.1 500 99.678Se [ ug/l ] 1.78 2 15 100.5 1000 103.488Sr [ ug/l ] 3.60 10 100 106.4 1000 106.3

95Mo [ ug/l ] 0.002 0.01 0.1 106.7 1 103.1107Ag [ ug/l ] 0.41 2 15 104.3 1000 100.9114Cd [ ug/l ] 0.25 0.4 4 94.6 1000 100.6118Sn [ ug/l ] 1.77 10 100 106.4 1000 104.5121Sb [ ug/l ] 1.35 2 10 99.3 1000 103.0126Te [ ug/l ] 0.87 1 10 101.0 1000 104.6135Ba [ ug/l ] 4.47 10 100 105.2 1000 103.3142Ce [ ug/l ] 3.57 10 100 102.1 1000 100.8201Hg [ ug/l ] 0.05 0.1 1 95.4 10 95.3

203Tl [ ug/l ] 3.08 10 100 101.4 1000 104.3208Pb [ ug/l ] 2.73 5 40 101.8 1000 103.1

Required MDLs met or exceeded – e.g. Hg x2

Spike recoveries at 2 levels typically within 5% of target

Results – CRM dataBCR-145R FeNeLab ISE (1) FeNeLab (2) Internal Control

charts (3)

Analyte Unit Measured CertifiedRecovery

(%)Measured Certified

Recovery (%)

CertificateRecovery

(%)Target

Recovery (%)

9Be [ ug/l ] 0.41 1.68 1.52 110.511B [ ug/l ] 18.72 35.10

23Na [ mg/l ] 0.65 0.33 0.333 97.7 0.374 87.024Mg [ mg/l ] 5.32 9.15 9.4 97.3

27Al [ mg/l ] 21.48 28.42 25.6 111.0 29.873 95.131P [ mg/l ] 11.80 2.45 2.52 97.3 2.74 89.534S [ mg/l ] 12.33 0.91 1.23 74.139K [ mg/l ] 1.36 6.42 5.25 122.2 7.172 89.5

44Ca [ mg/l ] 45.61 35.47 36.5 97.247Ti [ ug/l ] 204.64 504.7951V [ ug/l ] 28.55 64.03 55.8 114.7

52Cr [ ug/l ] 289.57 300 96.5 193.66 180 107.6 186 104.1 197 98.355Mn [ ug/l ] 0.14 0.145 96.2 1.03 1.05 98.5

September 28, 201117

56Fe [ ug/l ] 12.54 35.54 35.2 101.059Co [ ug/l ] 4.83 5.3 91.2 19.03 18.4 103.4 18.8 101.260Ni [ ug/l ] 224.33 251 89.4 56.81 54 105.2 53.8 105.6 57.1 99.5

63Cu [ ug/l ] 652.40 707 92.3 151.27 153 98.9 158 95.766Zn [ ug/l ] 1963.83 2140 91.8 1019.10 1020 99.9 1009 101.075As [ ug/l ] 8.01 44.62 41.6 107.3 43.7 102.178Se [ ug/l ] 6.36 1.80 1.71 105.188Sr [ ug/l ] 294.20 139.88 129 108.4

95Mo [ ug/l ] 0.01 0.00 0.00141 103.7107Ag [ ug/l ] 13.39 3.06 2.75 111.2114Cd [ ug/l ] 3.10 3.43 90.4 8.30 8.24 100.8 8.5 97.7 8.05 103.1118Sn [ ug/l ] 58.22 24.32 22.2 109.6 23.8 102.2121Sb [ ug/l ] 12.00 2.56 3.28 78.0 3.07 83.4126Te [ ug/l ] -0.03 0.29135Ba [ ug/l ] 2446.58 857.95 797 107.6 821 104.5142Ce [ ug/l ] 18.90 89.62201Hg [ ug/l ] 1.84 1.99 92.5 3.64 3.81 95.6 4.07 89.5 3.98 91.5

203Tl [ ug/l ] 0.16 1.25 1.1 114.0208Pb [ ug/l ] 256.17 282 90.8 291.08 283 102.9 279 104.3 306 95.1

Results – Within run stability

1.00

1.10

1.20

Be B Na Mg

Al K Ca Ti

• 12 hour run of undiluted Waste water digests

• Repeat analysis of QC material throughout run

• Target specification of +/- 10% met for all analytes

September 28, 201118

0.00

0.10

0.20

0.30

0.40

0.50

0.60

0.70

0.80

0.90

1 2 3 4 5 6 7 8 9 10 11

Ti V

Cr Mn

Fe Co Ni

Cu Zn As

Se Mo Ag

Cd Sn Sb Te Ba Ce

Hg Tl

Pb

Nor

mal

ised

reco

very

Case Study 2 – Analysis of river sediments from abandoned mine in Wales • 60 river sediment samples

were taken from river catchment of abandoned Pb/Zn mine

• Samples analysed for 38 elements by 7700x to build mixing model for areamixing model for area

September 28, 201119

Methods1. Sample preparation

– 0.5g of sediment dried + sieved

– Digested with 2mL conc HNO3 made up to 20mL H2O

2. Analysis

- Analysed directly by AA for major contaminants (Cu, Zn, Pb)

- Analysed after further 20x dilution by 7700x ICP-MS

September 28, 201120

Parameter Setting

Plasma Power 1550W

Carrier gas 0.94 L/min

Make-up gas 0.15 L/min

Sampling depth 8mm

Extract 1 0V

Helium flow (for collision cell) 4.3 mL/min

CeO/Ce 0.43%

Analyte list:38 elements including Hg in one run:Sc, Ti, V, Cr, Co, Ni, As, Rb, Sr, Y, Zr, Nb, Mo, Cd, In, Sn, Sb, Cs, Ba, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Hg, Tl, Bi, Th, U

Analysis time: 5 min per sample

Preliminary ResultsLong term stability:No significant change in

instrument response over 8 hours of continuous analysis

QC dataSoil QC material from USGS

analysed to check accuracy for range of elements

September 28, 201121

Element Compiled value(ppm)

Measured value(ppm)

V 54.0 55.3

Cr 3.2 3.5

Rb 73 72

Y 24 20

Zr 185 187

Mo 2.6 2.5

Cs 1.75 1.57

Pb 20.4 20.1

Th 4.5 4.6

U 1.9 1.6

Comments from the analyst (Dr Bill Perkins)The 7700 does many things for us as environmental geochemists that were

not possible with previous generation instruments:

1. The ability to look at key contaminants in samples – As, Se, V, Cr without the problems of matrix interferences;

2. The ability to look at low levels of Fe in solution;

3. Ease of operation with high levels of automation;

4. Stability – as shown by the long runs with minimal changes in the IS;4. Stability – as shown by the long runs with minimal changes in the IS;

5. Productivity – with the programmable rinse pre empting the sample change. Also the ISIS (but we have not really investigated this yet).

6. Productivity – the HMI which will remove the necessity to dilute samples in the future.

September 28, 201122

Conclusions

1. With the acquisition of Varian in May 2010, Agilent Technologies are in a position to providea full range of leading Atomic Spectroscopy instruments, from high-productivity AAS systemsto the market leading 7700 ICP-MS

2. The 700 OES series include a number of features designed to improve productivity andanalytical performance such as the unique CCI and simultaneous full spectrum coverageprovided by the CCD detector

3. The combination of HMI and the performance of the ORS3 cell in the 7700x in terms of bothsensitivity and interference removal provide new options for high-matrix analysis:

– Much higher TDS tolerance (up to 3-4% TDS, compared to 0.1 – 0.2% on conventional systems)

– Universal interference removal of polyatomics with 7700 Helium mode

– Single ICP-MS analysis covering all analytes � significant improvement in running costs, setup time,analysis time, data checking, etc.

4. The aqua regia MW digestion combined with direct analysis by Agilent 7700x ICP-MS is nowroutinely used at Eurofins Analytico for wastewater analysis.

September 28, 201123

Acknowledgements

Case study 1 data courtesy of Wim Proper, Eurofins Analytico

Case study 2 ICP-MS data courtesy of Dr Bill Perkins, University of Aberystwyth

Samples for case study 2 provided by Paul A. Brewer, Mark G. Macklin, Sara Rassner and Marc Huband

NERC-funded project with School of Ocean Sciences, Bangor UniversityNERC-funded project with School of Ocean Sciences, Bangor University

ICP-OES information from Jörg Hansmann, Agilent Technologies

Thank you for your attention!

September 28, 201124

Coming soon…

September 28, 201125

New Atomic Spectroscopy product from Agilent Technologies will be introduced to the UK market on October 5th at the Motorcycle Museum in Birmingham

To find out more about the launch event please visit the Agilent booth


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