Real-time monitoring of chemicals in water environment

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