Determination of Total Iodine using ICP-MS in Israeli Bottled and Tap Water: Method Development and Application

In Israel, desalinated water is a major source of drinking water. Previous studies have suggested that
the levels of iodine in water provided by authorities may not accurately reflect the levels reaching end-users.
Materials and Methods: We analyzed 21 tap water samples collected from different localities across Israel, 13 posttreated
desalinated water samples from three of the largest Israeli desalination plants, and several natural water
samples. An improved method of ICP-MS developed in our laboratory was used to analyze the content of iodine
and other macro-elements, and determination of iodine was performed in alkaline media.
Results: Our results showed that it is possible to distinguish between sample groups based on iodine concentration,
water hardness, and Ca/Mg ratio. The median iodine concentrations for four groups of tap water samples
ranged from 0.3 to 12.3 μg/L, which is lower than the concentrations previously reported by other researchers in
Israel. Based on typical consumption, the water samples can provide no more than 3.39% of the recommended
dietary allowance level for iodine. The analysis of post-treated desalinated water samples indicated that these
waters comply with industrial specifications but contain only trace concentrations of iodine and much less
magnesium than recommended by different public health authorities for public consumption of drinking water.
Conclusion: The total iodine concentrations found were lower than several observations reported in previous
years in the literature. There are currently no strict regulations regarding iodine and magnesium levels in
drinking and/or softened (desalinated) water, but the intensive desalination plant application is already
exhibiting a negative impact on public health. Further investigations are needed, but the present study provides
useful insights for developing an effective policy to ensure adequate iodine supply for the population of Israel
through drinking water.

1. Determination of Total Iodine
using ICP-MS in Israeli Bottled
and Tap Water: Method
Development and Application
Dr Vasiliy V. Rosen
[email protected]
The Scientific Service Core Facility
The Faculty of Agriculture
The Hebrew University of Jerusalem
January 17, 2023
The Team:
Dr Orit Gal
Yuliana Andrushchenko, M.Sc.
Prof. Yona Chen

2. Agenda
The Scientific Service Core Facility January 18, 2023 Slide No. 2
❑Iodine in drinking water in the desalination era
❑Iodine determination challenges
❑ICP-MS method improvement
❑Iodine in Israel: Tap water vs Bottled water

3. The Scientific Service Core Facility January 18, 2023 Slide No. 3
Iodine in drinking water in the desalination era
❖Essential micro-element for human health
❖The standard still not established, but: risk-reducing
concentrations of iodide in drinking water is about
5 – 50 µg L
-1
❖RDA 150 µg d
-1

❖EAR 95 µg d
-1

for females and males of age 14-50 y.
❖Discovered in 1811
❖Occurs in water mostly as iodate I
-

4. Iodine in drinking water in the desalination era
❖Do we consume enough iodine in Israel?
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5. Iodine in drinking water in the desalination era
2007
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6. Iodine in drinking water in the desalination era
Ashkelon Desalination Plant
118 million m
3
per year
Tenne A. et al., 2012
❖Desalination plants are
providing about 80% of
potable water used in
households across Israel
❖Iodine in tap water:
Ashkelon District: 2003 – 52 µg L
-1
,
2008 - 27 µg L
-1
(Gefel et al., 2016)
4 -20 µg L
-1
(Barnett-Izhaki et al., 2022)
The Scientific Service Core Facility January 18, 2023 Slide No. 6

7. Organically-
bound Iodine
(Organic
Iodides)
Iodide I- Iodate IO
3-
Free Iodine I
2
3I
2 + 3H
2O = HIO
3 + 5HI
In the alkaline media
In the acidic media
volatile non-
volatile
Iodine determination challenges
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8. ICP-MS Method Improvement
Iodine using ICP-MS
Superior sensitivity (LOQ~0.01 µg L
-1
)
High-throughput method
Expensive equipment
Method development challenge
+2% NH4OH, pH>10
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9. +2% NH4OH, pH>10
+2% NH4OH, pH>10
+0.1% EDTA
Carbonates precipitated
ICP-MS nebulizer
clogged
Carbonates have not formed
No clogging!
ICP-MS Method Improvement
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10. ICP-MS Method Improvement
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11. ICP-MS Method Improvement
Result Obtained (n=5):
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12. Method
Precision
ICP-MS Method Improvement
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13. ICP-MS Method Improvement
Cs
133
Ge
72
I
127
Internal Standard for I
127Element
Abundance,
%
Ion Potential,
eV
Atomic Mass,
amu
Cs 27.6 3.89 132.9
Ge 100 7.89 72.6
I 100 10.5 126.9
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14. ICP-MS Method Improvement
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15. ICP-MS Method Improvement
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16. ❖Iodine is stable in
matrices A and E
❖Iodine is stable in
original water sample
during 2 weeks at +4 ºC
or at room temperature
as is
+4 ºC
Room T
ICP-MS Method Improvement
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17. Total Iodine Concentration in Mineral Bottled Waters in Israel, µg L
-1
Aqua Nova
<0.1
Evian
1.53±0.03
S.Benedetto
3.47±0.03
Neviot
5.22±0.07
Mei Eden
6.89±0.13
Brand F
6.96±0.23
Brand G
8.46±0.11
Brand H
21.13±0.45
Tap Water
2.99±0.06
Iodine in Israel: Tap water vs Bottled water
7.68±2.41 µg L
-1

(average ± standard error)
7 ±5.7 µg L
-1

(Benbassat et al., 2004)
The Scientific Service Core Facility January 18, 2023 Slide No. 17

18. Iodine in Israel: Tap water vs Bottled water
Median values range
for all the samples
0.3 – 12.3 µg I L
-1
Group A
<1 µg I L
-1
Group B
1-4 µg I L
-1
Group C
4-8 µg I L
-1
Group D
8-20 µg I L
-1
Total iodine in tap water
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19. Iodine in Israel: Tap water vs Bottled water
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20. Iodine in Israel: Tap water vs Bottled water
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21. Iodine in Israel: Tap water vs Bottled water
Total iodine in natural waters
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22. Iodine in Israel: Tap water vs Bottled water
Ca/Mg
36.2
Ca/Mg
14.6
Ca/Mg
2.56
Ca/Mg
2.44
Ca/Mg
66.1
Ca/Mg
169
Ca/Mg
31.3
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23. Iodine in Israel: Tap water vs Bottled water
The hourly and yearly dynamics of iodine in tap water
CV 12%
CV 56%
CV 151%
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24. Conclusions
+2% NH4OH, pH>10
+0.1% EDTA
LOQ is 0.04 – 0.1 µg I l
-1
2 weeks stability Iodine deficiency is
possible 
The Scientific Service Core Facility January 18, 2023 Slide No. 24

25. The Team:

Dr. Orit Gal Garber

Yuliana Andrushchenko, M.Sc.

Prof. Yona Chen
Dr. Vasiliy V. Rosen