analysis(of(organic(iodine(in( drinking(water(
TRANSCRIPT
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Analysis of Organic Iodine in Drinking Water
The use of TOI and a proposed TOXLCMS Parameter
David Reckhow, Kaoru Ikuma and Rassil Sayess University of MassachuseGs, Amherst, MA
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Outline
2
• FormaKon in Drinking Water • Public Health Concerns • TOX
– Current Method – RelaKonship to the DBP issue
• Indirect Data on TOI – Lab Tests from high-‐I waters – Field Data on I-‐THMs & others
• Some Direct Data on TOI – Method using ICP/MS – Results to date
• AlternaKve TOI Approaches – LC/MS/MS – LC/QTOF
• Conclusions & where do we go from here?
It’s one of my favorite recipes. I call it Total Organic Iodine
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FormaKon of Cl2-‐driven DBPs
3
Natural Organic Mater
Anthropogenic Chemicals
(PPCPs, Ag & industrial products)
Cl2 NaOCl
NH3
Br-‐, I-‐
OBr-‐, I3-‐
~90%
CO2 + Oxidized Organic Compounds • Acids • Aldehydes • Ketones • Nitrosamines
NH2Cl The non-‐halogenated DBPs
The Halogenated DBPs • THMs • HAAs and other haloacids • HaloaromaKcs • N-‐halo compounds • Halo-‐nitriles, aldehydes, nitros, etc
~10%
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John Rook & DBPs
• Found DBPs and brought them to the world’s aGenKon – Brought headspace analysis from the beer industry to drinking water
– Found trihalomethanes (THMs) in finished water
• Carcinogens !?! – Published in Dutch journal H2O,
Aug 19, 1972 issue – Deduced that they were formed as
byproducts of chlorinaKon – Proposed chemical pathways
Rook, 1974, Water Treat. & Exam., 23:234
1921-‐2010
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The first, and currently regulated DBPs
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• The HAAs Cl
ClCl C COOH
Br
ClCl C COOH
Br
ClBr C COOH
Br
BrBr C COOH
Trichloroacetic Bromodichloroacetic Chlorodibromoacetic TribromoaceticAcid Acid Acid Acid
(TCAA) Cl
ClH C COOH
Br
ClC COOH
Br
BrH C COOH
Dichloroacetic Bromochloroacetic DibromoaceticAcid Acid Acid
(DCAA)
H
HAA5 only 5
Cl
ClCl C H
Br
ClCl C H
Br
ClBr C H
Br
BrBr C H
Chloroform Bromodichloromethane Chlorodibromomethane Bromoform
The THMs
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DBP Epidemiology
• Bladder Cancer – DBPs linked to ~10,000 US cases every year
• Other Cancers – Rectal, colon
• ReproducKve & developmental effects – Miscarriages & Low birth weight – Birth Defects
• e.g., Clej palate, neural tube defects
• Other – Kidney & spleen disorders – Immune system problems, neurotoxic effects
Basis for current EPA regulaNon
80 µg/L THMs 60 µg/L HAAs
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Single Cell Gel Electrophoresis Genotoxicity PotencyLog Molar Concentration (4 h Exposure)
10-6 10-5 10-4 10-3 10-2
IAA
BAA
CAA
DIA
ATB
AA
DBA
A3,3-
Dib
rom
o-4-
oxop
enta
noic
Aci
d
2-Br
omob
uten
edio
ic A
cid
2-Io
do-3
-bro
mop
rope
noic
Aci
d2,
3-D
ibro
mop
rope
noic
Aci
d
DBN
M
BDC
NM
TBN
M
TCN
M
BNM
BCN
MD
BCN
M
DC
NM
CN
M
Brom
oace
tam
ide
Dib
rom
oace
tam
ide
Trib
rom
opyr
role
MX
Brom
ate
EMS
+Con
trol
Haloacetic Acids
Halo Acids
Haloacetamides
Halonitromethanes
Other DBPs
DBP Chemical Class
Not Genotoxic: DCAA, TCAA, BDCAA, Dichloroacetamide, 3,3-Dibromopropenoic Acid, 3-Iodo-3-bromopropenoic Acid, 2,3,3,Tribromopropenoic Acid July 2006
Chl
oroa
ceta
mid
e
Trih
loro
acet
amid
e
Iodo
acet
amid
e
Haloacetonitriles Brom
oace
toni
trile
Dib
rom
oace
toni
trile
Brom
ochl
oroa
ceto
nitri
le
Chl
oroa
ceto
nitri
le
3,3-
Brom
ochl
oro-
4-ox
open
tano
ic A
cid
Iodo
acet
onitr
ile
Tric
hlor
oace
toni
trile
Dic
hlor
oace
toni
trile
BIAA
CD
BAA
BCAA
• Mono-‐X > Di-‐X > Tri-‐X • I > Br > Cl
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Genotoxicity The regulated ones
From Plewa & Colleagues
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Other Compounds The DBP Iceberg
Halogenated Compounds
Non-‐halogenated Compounds
ICR Compounds
50 MWDSC DBPs
~700 Known DBPs
THMs, THAAs
DHAAs
Stuart Krasner MWDSC
Susan Richardson USC
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• We need to know what these compounds are first
9 “I think you should be more explicit here in step two”
Control of Non-‐Regulated DBPs
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2D Graph 1
Unknown TOX (µg/L)
0 100 200 300 400
TTH
M (µ
g/L)
0
20
40
60
80
100
120
140
Unk-TOX vs TTHMc
Regulated DBPs as surrogates or indicators
• Not a perfect correlaKon
• So what can we do? – Maybe we need
a more diverse group of surrogates
– Look at occurrence characterisKcs
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From: ICR Database
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TOX: Known & Unknown
Trihalomethanes20%
Sum of 5 Haloacetic Acids10%
Bromochloroacetic Acid3%
Unknown Organic Halogen64%
Chloral Hydrate1%
Haloacetonitriles2%
HaloketonesChloropicrin
Data from the Mills Plant (CA) August 1997 (courtesy of Stuart Krasner)
Regulated DBPs
But, the Bad Stuff is probably
somewhere here?
Unknown TOX
TTHMs
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METHODS & ISSUES TOX as Measured Today
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Total Organic Halogen
• Standard Methods; USEPA Method #1650 • AcKvated Carbon AdsorpKon & Pyrolysis & Microcoulometric DetecKon of halide
• Extended Method for TOCl, TOBr, TOI • Trap gases & ion chromatography
– (e.g., Hua & Reckhow, 2008)
Pyrolysis Oven Microcoulometric
Cell
GAC AdsorpKon
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TOX in Drinking Water
• Originally proposed by researchers at the University of Karlsruhe in the 1970s – Led to development of commercial instrument: Dohrmann, Euroglass, Mitsubishi (current)
• Proposed regulatory acKon for TOX – As a surrogate for unknown DBPs – Eventually deemed too problemaKc by EPA and others to pursue
• Although EU has a TOX guideline
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Why is TOX not regulated? • Mostly problems with method
– Costly instrumentaKon that is only used for TOX – Difficult to operate and not easily automated – High and variable GAC blanks limit precision and sensiKvity
– Recovery is not good for all compounds – Chemical informaKon can be expanded to specific halogens, but this may require special accommodaKons for TOBr and TOI (e.g., ICP/MS)
– The most important informaKon is not accessible • number and type of halogens per molecule
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DATA FROM WATERS HIGHLY FORTIFIED WITH IODIDE
What do we know about TOI
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IO3-
Cl2 O3/Cl2 NH2Cl O3/NH2Cl ClO2
I-TH
M (µ
g/L)
0
10
20
30
40CHCl2ICHClI2CHBrClICHBr2ICHBrI2CHI3
IO3- (µ
g/L)
0
100
200
300
400
Cambridge MA Water, DOC: 4.2 mg/L, I: 200 µg/L Hua & Reckhow, 2007
Iodo-‐THMs O3
O3
Chlorine & Ozone produce iodate; Chloramine doesn’t
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Iodinated TOX (TOI)
Con
cent
ratio
n (µ
g C
l/L)
0
100
200
300
400
500TOClTOI
O3 Cl2 O3/Cl2 NH2Cl O3/NH2Cl ClO2
Cambridge MA Water, DOC=4.2 mg/L, I-=200 µg/L (added)
TOI : NH2Cl > ClO2 > Cl2 > O3
Hua & Reckhow, 2007 18
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DATA FROM A FEW STUDIES MEASURING I-‐THMS
What do we know about TOI
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Iodo-‐DBP Occurrence
• Iodo-‐THM Occurrence – ConcentraKons
• From 12 systems in NA • Up to 25 µg/L for direct chloraminaKon
– RelaKve Prevalence • 2% of THM4 at 50%ile; 7% at 75%ile? • Iodo-‐THMs ≈ 0.1* Bromo-‐THMs
• Iodo-‐HAA Occurrence – LiGle or no triHAAs containing iodine??
From: Weinberg, Krasner, et al., 2002
PercenNle Conc (µg/L)
50% 0.4
75% 2
90% 4
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Cl vs Br: Species Model
THM Br/(Cl+Br)
0.0 0.2 0.4 0.6 0.8 1.0
THM
Mol
e Fr
actio
n (T
HM
4 on
ly)
0.0
0.2
0.4
0.6
0.8
1.0
1.2
Probabilistic model
CHCl3
CHBrCl2 CHBr2Cl
CHBr3
• Simple compeKKve kineKc model: applicable to all DBPs? – From: MacNeill, 1993; Cowan & Singer, 1996
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22 THM Br/(Cl+Br)
0.0 0.2 0.4 0.6 0.8 1.0
THM
Mol
e Fr
actio
n (T
HM
4 on
ly)
0.0
0.2
0.4
0.6
0.8
1.0
1.2
CHCl3CHBrCl2CHBr2ClCHBr3CHCl3 Lab testsCHBrCl2 Lab testsCHBr2Cl Lab testsCHBr3 Lab tests
Full-scale data (small symbols) from Weinberg et al., 2002 (All 12 plants)
Lab data (large symbols) from Hua & Reckhow, 2004Lines are geometric model
Bromo-‐chloro speciaKon for THMs Strong oxidants such as ozone or chlorine dioxide upset this relaKonship
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EsKmaKng I-‐THM Occurrence • I originates from sea water
– More volaKle than Cl or Br, so conKnental waters are relaKvely enriched in I
– SKll, I should be roughly correlated with Br
• I-‐THMs are related to iodide concentraKon – Just as Br-‐THMs are related to
bromide level • Therefore I-‐THM fracKon
should be posiKvely correlated with Br-‐THM fracKon
THM Br/(Cl+Br)
0.0 0.1 0.2 0.3 0.4 0.5
THM
I/(C
l+I)
0.00
0.02
0.04
0.06
0.08
0.10
0.12
0.14
0.16
0.18
0.20
All but plant #12
b[1]=0.095
DS Data from Weinberg et al., 2002
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Iodo speciaKon is similar • Only low THM I data
available from field sites • SuggesKons of departure
from probabilisKc model at high THM I – Higher iodoform than
expected – Possible decomposiKon of
larger TOI structures
THM I/(Cl+I)
0.0 0.2 0.4 0.6 0.8 1.0
THM
Mol
e Fr
actio
n (C
l&I o
nly)
0.0
0.2
0.4
0.6
0.8
1.0
1.2
CHCl3CHICl2CHI2ClCHI3CHCl3 Lab testsCHICl2 Lab testsCHI2Cl Lab testsCHI3 Lab tests
Full-scale data (small symbols) from Weinberg et al., 2002 (All 12 plants)
Lab data (large symbols) from Hua & Reckhow, 2004Lines are geometric model
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DATA FROM MODEL COMPOUND STUDIES
What do we know about TOI
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Many Iodo-‐acids decompose
• DecarboxylaKon rates of THAAs in water – From Zhang and Minear, 2002; expanded by UMass
HAA 20C 55C 20C 55C degradation product (THM)TCAA 99000 130 100.0% 88.0% chloroformBDCAA 21600 36 99.9% 63.0% bromodichloromethaneDBCAA 4400 8 99.6% 12.5% chlorodibromomethaneTBAA 620 3 97.4% 0.4% bromoformDCIAA 2414 3.2 99.3% 0.5% dichloroiodomethaneBCIAA 479 0.63 96.6% 0.0% bromochloroiodomethaneDBIAA 95 0.12 84.0% 0.0% dibromoiodomethaneCDIAA 62 0.08 76.5% 0.0% chlorodiiodomethaneBDIAA 12 0.02 26.0% 0.0% bromodiiodomethaneTIAA 2 0.00 0.0% 0.0% triiodomethane
Half-‐life (hr) % Remaining @ 24 hr
DistribuKon System Water Heater
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USE OF ICP/MS FOR QUANTIFICATION OF I IN TOX
How can we actually measure ambient TOI?
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• DetecKon of Br and I
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Improved MDL with ICP/MS
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Standard Curves with ICP/MS
• Especially good for Iodine
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y = 6840.7x R² = 0.9958
0 100000 200000 300000 400000 500000 600000 700000 800000 900000
0 20 40 60 80 100 120 140 I127
Inte
nsity
usi
ng IC
P/M
S
Concentration (ugI/L)
I127 Standard Curve
y = 511.71x + 805.61 R² = 0.99504
0
10000
20000
30000
40000
50000
60000
0 20 40 60 80 100 120 Br 8
1 In
tens
ity u
sing
ICP/
MS
Prepared concentration (ugBr/L)
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Method DetecKon Limit
• ICP/MS detecKon of halides (µg/L)
30
Set
Iodide Bromide Measured concentraKon (ugI/L) MDL LOQ
Measured concentraKon (ugBr/L) MDL LOQ
High Replicate
1.74
0.49 1.57
0.97
0.58 1.85
2.10 0.81 2.16 1.04 1.80 1.28 1.91 1.24 1.82 1.32 1.87 1.08
Low Replicates
1.28
0.19 0.61
0.89
0.98 3.13
1.35 0.73 1.40 0.22 1.23 0.03 1.35 0.58 1.32 0.42 1.25 0.77
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TesKng TOI recovery with ICPMS • Recovery in TOI is ojen good but not always
31
Analyte
Prepared concentraNon (ugI/L)
ConcentraNon in original soluNon (ugI/L)
Iodine Recovery (%)
Total Iodine Recovery (%)
Iodo-‐aceNc Acid
Raw
126.90
116.12 91.5% 1st collected effluent 21.19 16.7%
91% 2nd collected effluent (nitrate soluKon) 10.51 8.3%
TOX 83.56 65.8%
Iodoform
Raw
114.21
130.44 114.2% 1st collected effluent 34.78 30.5%
78% 2nd collected effluent (nitrate soluKon) 22.07 19.3%
TOX 31.66 27.7%
Iodo-‐toluene
Raw
152.28
1st collected effluent 46.19 30.3%
72% 2nd collected effluent (nitrate soluKon) 10.44
6.9%
TOX 53.00 34.8%
Tri-‐iodoaceNc Acid
Raw
152.28
1st collected effluent 14.24 9.4%
47% 2nd collected effluent (nitrate soluKon) 1.53
1.0%
TOX 55.96 36.7%
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Where does the missing X go?
• Not adsorbed? • Washed out?
sample
For disposal
First column
Second column
Combusted first
Combusted second
~67% or more
organics
~33 % or less organics
Trapping Combustion
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GAC breakthrough characterisKcs
• The non-‐exceedance probability diagram of the 1st:2nd column recovery raKo of TOCl, TOBr, and TOI.
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TARGETING HAAS AND ICMS Field Studies using actual treated drinking waters
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Target List: Searched Following Full Spectral QTof AcquisiKon
¡ For each compound, a structure was loaded and associated with the target list
¡ Fragment masses were obtained from a literature source which uKlized MRMs; exact masses were calculated from these known fragments and entered in the component search
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ESI negative mode
MonoiodoaceKc acid
TriiodoaceKc acid
Iodide
Iodide
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ESI positive mode
Iopromide
Iopamidol
Iohexol
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ESI negative mode (MSe)
Low fragmentaKon energy channel
High fragmentaKon energy channel
Iohexol
Iopromide
Iopamidol
Iodide fragment
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Searching for Unknown Iodinated Compounds
¡ Neutral Loss Search: from list of unassigned masses, the neutral loss of –I was performed by searching for the difference of 126.9045 between the low energy spectrum and high energy spectrum
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Searching for Unknown Iodinated Compounds
¡ Common Fragment Search: from list of unassigned masses, the common fragment of –I (m/z 126.9052) was performed by searching for said fragment in high energy spectrum
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Proposed IdenKficaKon 1
¡ Elemental ComposiKon computaKon is based on isotope distribuKon paGern in observed spectrum and selected elements for search
¡ Result for 419.1251 = C22H29I ¡ Mass Error for proposed ID = 2.2 ppm
Low Energy Channel
High Energy Channel Raw Water
Finished Water #1
Finished Water #2
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Proposed IdenKficaKon 2
¡ Result for 811.8210 = C19H5ClIN7O20 ¡ Mass Error for proposed ID = -‐4.9 ppm
Low Energy Channel
High Energy Channel Raw Water
Finished Water #1
Finished Water #2
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Conclusions
• TOX is sKll quite relevant to assessing adverse health effects in drinking water, however: – Halogen specific detecKon is needed – More structural informaKon would improve its usefulness
• Standard methods cannot be used to measure TOI – SoluKon: incorporate ICP/MS
• ConvenKonal TOX loses key structural informaKon – SoluKon: use LC/QTOF with modern methods of data analysis as an alternaKve
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Acknowledgments
• Waters CorporaKon – Especially: Lauren Mullin
• NaKonal Science FoundaKon – Major Research InstrumentaKon program
• Mitsubishi -‐ Cosa
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