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Real-time monitoring of chemicals in water environment
Dr. Xize NiuUniversity of Southampton
Workshop on Smart Infrastructure
Motivation: in situ nutrients/pollutants monitoring
o High cost and maintenanceo Interference and accuracy High power consumption Low measurement frequency
Challenges exist:
Monitor Station YSI Data Buoy in ChinaAdverse effects of
nutrient enrichment
Workshop on Smart Infrastructure
Microfluidic chemical sensors (Hywel Morgan, ECS; Matt Mowlem, NOC)
Beaton et al., Env. Sci & Tech., 2012, 46 (17), 9548
Miniaturisation of established protocols
Robust, good analytical performance (e.g. LOD 25 nM)
Limited by Taylor dispersionLimited measurement frequency
11/1/2019 4
aqueous aqueous
oil
100 µm
B: What is droplet microfluidics?
sample reagent
• No carry over/washing
• No dispersion
• Rapid mixing
• High throughput
Advantages: Continuousmicrofluidics
Droplet microfluidics
Here we take a new approach
Droplet microfluidics
Exqample: droplet microfluidic sensor for nitrate/nitrite measurement
VCl3
HeatNO3
-Sulfanilimide
NEDDNO2
- Coloured product
Heater
Nightingale, A. et. al. Environmental Science & Technology 2019 53 (16), 9677-9685
Hassan, et.al. Analyst, 2016, 141, 3266
Optical detection – droplet flow cell
Integrated Droplet microfluidic sensor
Deployable in water, in station, on profiling vehicles and be able to form sensor networks.
Measures every 10 s (>8000 data/day)Detection limit. 0.3 𝜇M Reagent consumption: 350 nL/sample
2.8 mL/dayPower consumption: ~1.5 W
C. Sensor GUI and real-time data
Deployment in tidal riverC. Deployment at river Itchen, Southampton Deployment in tidal river
300
400
500
600
TO
N (M
)
0
5
10
Conductivity
(mS
/cm
)
0
5
Tid
eheig
ht
(m)
205 210 215 2200
20
Local ra
infa
ll(m
m/d
ay)
Day number, 2018
C. Measurement in the summer 2018
Error < 6%
Correlates withsalinity, tide & rainfall
Summary of the chemical analyser
One litre reagent support for one year
Platform technology (miniaturising wet chemical assays)
(Nitrate, Nitrite, Phosphate, silicate, ammonium)
Small footprint, low cost, measures in situ and real-time.
High measurement frequency (10 s per measurement)
Low reagent usage (2.8 ml/day continuously measuring)
Support sensor network and profiling vehicles
11/1/2019 Dr. Xize Niu 12
Glucose, Lactate, Pyruvate Histamine, Cortisol, …
Drugs: Heparin, Lithium,Antimicrobials …
Micro- macro- molecules Nitrate, Nitrite Phosphate, silicateammonium
From prototypes to products
Current Projects, Challenges
UK – Ecology & Hydrology (CEH),
UK – Environmental Agency
Germany – Water Utility Wiesbaden
Chinese Academy of Sciences (CAS)
Water Sensors (NERC), with:
UK – UoS (Tiina Roose, Adrian Nightinalge)
UK – Reading Univ (Liz Shaw)
US – Univ Connecticut (Baikun Li)
US – Univ New Hampshire (Md Shaad Mahmud)
Soil Sensors (NERC – Signals in Soil), with:
Science & Engineering:
Data, Power, Miniaturised optics, Robust chemistry & Engineering,
Challenges:
Finance & HR:
Real-time monitoring of chemicals in water environment
Dr. Xize [email protected]
Workshop on Smart Infrastructure
