This document discusses current and future technologies for detecting alcohol. It describes several non-enzymatic techniques like gas chromatography and HPLC that are complex, time-consuming and expensive. Enzymatic methods using alcohol oxidase or alcohol dehydrogenase in biosensors are more promising as they are simpler and cheaper. Various types of biosensors using these enzymes are outlined, including amperometric, potentiometric and optical sensors. Recent work on third generation, visual, and electrochemiluminescence biosensors as well as disposable strips are summarized. Overall, the document evaluates different alcohol detection methods and suggests further development of low-cost, portable enzymatic biosensors is needed.

1. CURRENT TECHNOLOGY AND
FUTURE PROSPECT FOR DETECTION
OF ALCOHOL
By: Phurpa Dema Thungon
146106001

2. DETECTION OF ALCOHOL
 Accurate and rapid measurement of alcohol in
order to analyze human body fluids for checking
ethanol content
 The food, beverage and pulp industries require
simple, fast and economic analytical methods in
order to control fermentation processes and the
quality of products
 In agricultural and environmental analysis, e.g. for
the assessment of ethanol at a spill site or in
groundwaters
 Screening for alcohol problems: Drivers and
alcoholics
 Major work on Ethanol

3. NON-ENZYMATIC TECHNIQUES FOR
QUANTIFICATION OF ETHANOL
GC= gas chromatography; FID = flame-ionisation detection; MS= mass spectroscopy; HPLC = high performance liquid chromatography;
IR = infrared; NIR = near infrared; FT = Fourier transform
 However: Complex, time consuming and require
previous separations processes (distillation..)
 Expensive instrumentation and trained operators
 Overcome by the use of enzymatic methods

4. ENZYMES FOR ETHANOL BIOSENSORS
 Alcohol Oxidase (AOX) and Alcohol Dehydrogenase (ADH)
ALCOHOL OXIDASE
 Produced by methylotrophic yeasts during growth
on methanol
 Cofactor- flavin adenine dinucleotide (FAD)
 Biosensors based on
 Decrease in O2
 Increase in H2O2 concentration

5. BIOSENSORS DEVELOPED USING ALCOHOL
OXIDASE
 O2 Probe- Electrochemical Detection and Optical
Detection
 H2O2 Probe
a) Direct (First generation biosensor)
b) Indirect method
(Second and Third generations)

6. THIRD GENERATION ALCOHOL BIOSENSOR
(2014)
• Ferrocene molecules entrapped in the AOX protein matrix
• Detection limit of 2.3 uM

7. VISUAL ETHANOL BIOSENSOR (2014)
 Dip Stick Test
 Polyaniline (PANI) is a polymer that changes
conductivity and colour with changes in pH or redox
reactions
 The colour change of the films towards ethanol has
been scanned and analyzed using image analysis
software (i.e., ImageJ)

8. PROPOSED REACTION MECHANISM
 Reduction of the PANI film from its emeraldine salt
form (green) to the emeraldine base form (blue)

9. ALCOHOL DEHYDROGENASE
 Co-enzyme nicotinamide adenine dinucleotide(NAD+)
 NAD+ to be added externally

10. ELECTROCHEMILUMINESCENCE ETHANOL
BIOSENSOR (2013)
 Electrochemiluminescence (ECL) is a process of
converting electrochemical energy into radiative
energy on the surface of electrode
 Based on tris(2,2′-bipyridine) ruthenium(II)
[Ru(bpy)3
2+ ] : good electrochemical stability, high
ECL efficiency, and the convenience to couple with
various separation techniques
 Alcohol Dehydrogenase

11. FORMATION OF ECL ETHANOL BIOSENSOR BASED
ON GRAPHENE/BSA COMPOSITE FILM

12. The CVs of the biosensor at the different scan rate in 100 mM PBS (pH 7.0).
a–g Correspond to scan rate: 20, 60, 100, 200, 400, 500 and 600 mV/S respectively.
(B) CVs of 100 mM PBS (pH 7.0) on the bare GCE (Curve b) and
the ECL ethanol biosensor (Curve a), and ECL–potential curve of bare GCE (Curve b′)
and the ECL ethanol biosensor (Curve a′) to 500 μM ethanol. Scan rate: 100 mV/s.

13. DISPOSABLE BIOSENSOR STRIP(2011)
 Alcohol dehydrogenase
 Screen-printed electrode modified with Meldola’s
Blue (MB) absorbed on Nafion
A) print conductive sliver strip
B)carbonic working counter electrodes
C)Ag/AgCl reference electrode
D) insulating layer (D)

14. PHOTOGRAPH OF THE BIOSENSOR

15. CONCLUSION AND FUTURE
 Keys features needed for alcohol biosensors
portability, low cost and potential for fabrication
immobilization of alcohol oxidase (AOD) or alcohol
dehydrogenase or any other enzyme
 ADH more popular in recent disposable ethanol
biosensors than AOX as it’s dry enzyme
preparation has low shelf life
 Disposable biosensor
 Majority of work done in Ethanol but not Methanol
which is considered as toxic

16. THANK YOU