a centrifugal lab-on-a-disc device for the in situ...
TRANSCRIPT
A centrifugal lab-on-a-disc device for the in situ determination of dissolved
reactive phosphate in water
Gillian Duffy, Brendan Heery, Ivan Maguire, Charles Nwankire, Jens Ducrée, Fiona Regan 1
Contents Background information
Centrifugal microfluidics
Analytical method on disc
Detection system
Integrated system
2
Phosphorus in water Growth limiting nutrient:
• algal bloom
• hypoxic waters
• death of aquatic animals
• toxic blooms
3 http://serc.carleton.edu/microbelife/topics/redtide/general.html
http://www.natureworldnews.com/articles/15693/20150717/toxic-algae-expected-lake-erie-potentially-worst.htm
http://sites.duke.edu/biology217_01_s2011_mkg14/ecological-impacts/eutrophication/
Traditional analysis
Grab sample
Travel
Storage
Analysis
Travel
4
• Time intensive
• Labour intensive
• Expensive
instrumentation
• Low sampling
frequency
• Contamination
Centrifugal microfluidics
5
Centrifugal force
Direction of rotation
Analytical method
6
Four methods:
High sensitivity
Selectivity
Simplicity
LOD and LOQ
Linear range
Analytical method
7
R² = 0.9983
R² = 0.9583
R² = 0.9377
R² = 0.9872 0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
0 100 200 300 400 500 600
Ab
sorb
an
ce (
AU
)
Concentration (µg L-1 PO4-P)
0
0.0002
0.0004
0.0006
0.0008
0.001
0.0012
0.0014
0.0016
0.0018
Se
nsi
tiv
ity
(A
U (
µg
L-1)-1
)
= ascorbic acid method
= stannous chloride method
= stannous chloride-hydrazine method
= yellow method
Analytical method
8
PO43- + 2(NH4)6Mo7O24.4H2O
𝑯𝟐𝑺𝑶𝟒 H3PMo12O40
1.
H3PMo12O40 + 2C6H8O6 + C8H4K2O12Sb2.3H2O
H7PMoV
4MoVI8O40 + 2C6H6O6 + 4H+ 2.
Detection system
9
increase
Microfluidic disc
10
Reservoir
Microchannel
Air vent
Detection chamber
11
Detection system
12
Roithner 880 nm laser Radionics 880 nm LED
Radionics photodiode
Optical path length study
LED (B)
Laser (A)
Photodiode B
Photodiode A
Optical path length 13
Optical path length study
R² = 0.9809
R² = 0.9985
-0.001
0
0.001
0.002
0.003
0.004
0.005
0.006
0.007
0 20 40 60 80 100
Se
nsi
tiv
ity
(AU
L µ
g-1)
Optical path length (mm)
Laser
LED
14
R² = 0.9098
R² = 0.796
0
0.001
0.002
0.003
0.004
0.005
0.006
0 20 40 60 80 100 120
Se
nsi
tiv
ity
(AU
L µ
g-1)
Optical path length (mm)
LED
Laser
Integrated NutriSense system
15
Black 3D printed container
Motor to be incorporated for disc rotation
Optical detection system is aligned on the stage
Electronics stored beneath, away from wet chemistry
Conclusion Analytical method
Disc design optimised Mixing
bubble formation
Optical path length
Integrated system designed – first prototype fabricated
16
Future work Incorporate motor into system
Investigate system robustness in situ
Adapt disc design for other analytes for water quality analysis
17
Acknowledgements Brendan Heery
Ivan Maguire
Prof. Fiona Regan
18
Thank you! 19