Expression, purification and spectroscopic characterization of the cytochrome...John Clarkson
K.J. McLean, M.R. Cheesman, S.L. Rivers, A. Richmond, D. Leys, S.K. Chapman, G.A. Reid, N.C. Price, S.M. Kelly, J. Clarkson, W.E Smith & A.W. Munro, “Expression, Purification and Spectroscopic Characterization of the Cytochrome P450 CYP121 from Mycobacterium Tuberculosis”, J. Inorganic Biochemistry, 91, 527-541, 2002.
Probing the chemistries of flavin ring systems of p hydroxybenzoate hydroxyla...John Clarkson
J. Clarkson, B. Pulfey & P.R. Carey, “Probing the Chemistries of Flavin Ring Systems of p-Hydroxybenzoate Hydroxylase by Raman Difference Spectroscopy”, Biochemistry, 36, 12560-12566, 1997.
Expression, purification and spectroscopic characterization of the cytochrome...John Clarkson
K.J. McLean, M.R. Cheesman, S.L. Rivers, A. Richmond, D. Leys, S.K. Chapman, G.A. Reid, N.C. Price, S.M. Kelly, J. Clarkson, W.E Smith & A.W. Munro, “Expression, Purification and Spectroscopic Characterization of the Cytochrome P450 CYP121 from Mycobacterium Tuberculosis”, J. Inorganic Biochemistry, 91, 527-541, 2002.
Probing the chemistries of flavin ring systems of p hydroxybenzoate hydroxyla...John Clarkson
J. Clarkson, B. Pulfey & P.R. Carey, “Probing the Chemistries of Flavin Ring Systems of p-Hydroxybenzoate Hydroxylase by Raman Difference Spectroscopy”, Biochemistry, 36, 12560-12566, 1997.
Volunteers in urban Forestry: Treasure or TroubleLee Mueller
For many cities, volunteers have become an increasingly critical part of urban forestry programs. However, whether you are engaging volunteers as part of your community outreach strategy or to help plant trees, volunteers can require significant amounts of time and resources to manage resources that are not always available. Luckily, if assigned the right projects and provided the right leadership, volunteers can add significant value to your forestry programs. This presentation will provide an overview of the value volunteers can provide, choosing effective volunteer projects, and recruiting volunteers. Specific attention will be given to volunteer training needs, efficient communication, and methods of identifying leaders. Participants can be expected to walk away with an understanding of how to appeal to volunteer leaders, the challenges to volunteer approaches, and
unique ways to keep volunteers engaged and supporting your community's work.
UV raman evidence of a tyrosine in apo human serum transferrin with a low p k...John Clarkson
J. Clarkson* & D.A. Smith, “UV Raman Evidence of a Tyrosine in Apo-Human Serum Transferrin with a Low pKa that is Elevated upon Binding of Sulfate”, FEBS Letts 503(1), 30-34, 2001.
Raman study of the polarizing forces promoting catalysis in 4 chlorbenzoyl-co...John Clarkson
J. Clarkson, P.J. Touge, K.L. Taylor, D. Dunaway-Mariano & P.R. Carey, “Raman Study of the Polarizing Forces Promoting Catalysis in 4-Chlorbenzoyl-CoA Dehalogenase”, Biochemistry, 36, 10192-10199, 1997.
Temperature fields during the development of combustion in a rapid compressio...John Clarkson
J. Clarkson, J.F. Griffiths, J.P. MacNamara, & B.J. Whitaker, “Temperature Fields During the Development of Combustion in a Rapid Compression Machine”, Combustion and Flame, 125, 1162-1175, 2001.
Ultraviolet resonance raman study of the avidin biotin complexJohn Clarkson
J. Clarkson*, C. Sudworth, S.I. Masca, D.N. Batchelder & D.A. Smith, “Ultraviolet resonance Raman study of the avidin biotin complex”, J. Raman Spectrosc., 31, 373-375, 2000.
The effect of core destabilisation on the mechanical resistance of i27John Clarkson
D.J. Brockwell, G.S. Beddard, J. Clarkson, R.C. Zinober, A.W. Blake, J. Trinick, P.D. Olmsted, D.A. Smith & S.E. Radford, “The Effect of Core Destabilisation on the Mechanical Resistance of I27”, Biophys. J., 83(1), 472-483, 2002.
UV resonance raman study of streptavidin binding of biotin and 2 iminobiotin ...John Clarkson
J. Clarkson*, D.N. Batchelder & D.A. Smith, “UV Resonance Raman Study of Streptavidin Binding of Biotin and 2-iminobiotin: Comparison with Avidin”, Biopolymers (Biospectoscopy), 62, 307-314, 2001.
PIOGA/MSC Observations/Questions on PA DEP Radiation in Shale Drilling StudyMarcellus Drilling News
A document produced in August 2013 jointly by the Marcellus Shale Coalition (MSC) and the Pennsylvania Independent Oil and Gas Association (PIOGA) questioning some of the criteria and scope of a proposed study now under way and being conducted by the PA Dept. of Environmental Protection (DEP). The DEP is studying the extent and scope of radiation in shale drilling waste, and whether or not they need to establish regulatory standards to control it.
Volunteers in urban Forestry: Treasure or TroubleLee Mueller
For many cities, volunteers have become an increasingly critical part of urban forestry programs. However, whether you are engaging volunteers as part of your community outreach strategy or to help plant trees, volunteers can require significant amounts of time and resources to manage resources that are not always available. Luckily, if assigned the right projects and provided the right leadership, volunteers can add significant value to your forestry programs. This presentation will provide an overview of the value volunteers can provide, choosing effective volunteer projects, and recruiting volunteers. Specific attention will be given to volunteer training needs, efficient communication, and methods of identifying leaders. Participants can be expected to walk away with an understanding of how to appeal to volunteer leaders, the challenges to volunteer approaches, and
unique ways to keep volunteers engaged and supporting your community's work.
UV raman evidence of a tyrosine in apo human serum transferrin with a low p k...John Clarkson
J. Clarkson* & D.A. Smith, “UV Raman Evidence of a Tyrosine in Apo-Human Serum Transferrin with a Low pKa that is Elevated upon Binding of Sulfate”, FEBS Letts 503(1), 30-34, 2001.
Raman study of the polarizing forces promoting catalysis in 4 chlorbenzoyl-co...John Clarkson
J. Clarkson, P.J. Touge, K.L. Taylor, D. Dunaway-Mariano & P.R. Carey, “Raman Study of the Polarizing Forces Promoting Catalysis in 4-Chlorbenzoyl-CoA Dehalogenase”, Biochemistry, 36, 10192-10199, 1997.
Temperature fields during the development of combustion in a rapid compressio...John Clarkson
J. Clarkson, J.F. Griffiths, J.P. MacNamara, & B.J. Whitaker, “Temperature Fields During the Development of Combustion in a Rapid Compression Machine”, Combustion and Flame, 125, 1162-1175, 2001.
Ultraviolet resonance raman study of the avidin biotin complexJohn Clarkson
J. Clarkson*, C. Sudworth, S.I. Masca, D.N. Batchelder & D.A. Smith, “Ultraviolet resonance Raman study of the avidin biotin complex”, J. Raman Spectrosc., 31, 373-375, 2000.
The effect of core destabilisation on the mechanical resistance of i27John Clarkson
D.J. Brockwell, G.S. Beddard, J. Clarkson, R.C. Zinober, A.W. Blake, J. Trinick, P.D. Olmsted, D.A. Smith & S.E. Radford, “The Effect of Core Destabilisation on the Mechanical Resistance of I27”, Biophys. J., 83(1), 472-483, 2002.
UV resonance raman study of streptavidin binding of biotin and 2 iminobiotin ...John Clarkson
J. Clarkson*, D.N. Batchelder & D.A. Smith, “UV Resonance Raman Study of Streptavidin Binding of Biotin and 2-iminobiotin: Comparison with Avidin”, Biopolymers (Biospectoscopy), 62, 307-314, 2001.
PIOGA/MSC Observations/Questions on PA DEP Radiation in Shale Drilling StudyMarcellus Drilling News
A document produced in August 2013 jointly by the Marcellus Shale Coalition (MSC) and the Pennsylvania Independent Oil and Gas Association (PIOGA) questioning some of the criteria and scope of a proposed study now under way and being conducted by the PA Dept. of Environmental Protection (DEP). The DEP is studying the extent and scope of radiation in shale drilling waste, and whether or not they need to establish regulatory standards to control it.
IQ4I Research published a new report on “Chromatography Global Market – Fore...Vinay Shiva Prasad
Chromatography is a versatile separation technique used across industries such as bio pharma & pharmaceutical, food & beverage, oil & petroleum, environmental testing and agriculture & chemical industries. Factors like Rapid rise in biologics, growing importance of chromatography tests in drug approvals are driving the market.
On the comparison of metals, heavy and toxics elements in waste petroleum of ...Dr. Mohamed Saad Seoud
Petroleum waste of scale, sludge and sand that maintained various level of naturally occurring radioactive materials could also contain heavy and toxic elements which cause hazardous pollution to human health and the environment so that determination of these elements in waste petroleum samples are important to refineries, industrial processes, waste disposal and transports. Thus, the present work will focus on the evaluation the concentrations of metals, heavy and toxics elements in waste petroleum samples from petroleum companies located in Egypt and Kuwait using Inductively Coupled Plasma Optical Emission Spectrometer (ICP-OES) and X-Ray Fluorescence (XRF) Techniques. 6 samples of scale, sludge and sand were collected, 3 samples from Kuwait petroleum companies and 3 samples from Egypt as well. More than 17 elements of metals, heavy elements and toxic metals of (Si, Cu, Al, S, K, Ca, Na, Mn, Fe, Zn, Pb, As, Br, Sr, Rh, Ba and Ti) were detected in the selected samples with various values. All the studied samples had high concentrations of Fe, K, Ca, S and Si rather than the other elements. The concentration of Iron in Egyptian samples was higher than in Kuwait samples whilst silicon and potassium were greater in Kuwait samples. All the other elements were almost same in Egyptian and Kuwait samples. Furthermore, the toxic element of barium was detected in Egyptian samples with high concentration but it was not detected in Kuwait samples (XRF). The two measurement methods show good agreement, No significant differences. The obtained results imply that the petroleum wastes need more monitoring in order to minimize the environmental pollution.
Collagen and bone fat are important resources in the food industry. It is essential that these primary products are odor- and taste free. Extensive de-odourization processes are used during bone fat & collagen processing to eliminate any off-flavors that might be present. Regular sensory evaluation performed by specially trained panels in combination with GC-MS analysis ensures product quality is not compromised.
Commerce Resources Corp. (TSXv: CCE, FSE: D7H) announced that a significant reduction in the consumption of three principal flotation reagents has been achieved in bench scale development testwork for the Ashram Rare Earth Deposit.
Raman microscopy and x ray diffraction a combined study of fibrillin-rich mic...John Clarkson
J.L. Haston, S.B. Engelsen, M. Roessle, J. Clarkson, E.W. Blanch, C. Baldock, C.M. Kielty & T.J. Wess, “Raman microscopy and X-ray diffraction: A combined study of fibrillin-rich microfibillar elasticity”, J. Biol. Chem., 278(42), 41189-41197, 2003.
Opportunities for probing the structure and mechanism of porphobilinogen synt...John Clarkson
J. Clarkson, E.K. Jaffe, R.M. Petrovich, J. Dong & P.R. Carey, “Opportunities for Probing the Structure and Mechanism of Porphobilinogen Synthase by Raman Spectroscopy.” J. Am. Chem. Soc., 119, 11556-11557, 1997.
Morphological study of aluminum tris(8 hydroxyquinoline) thin films using inf...John Clarkson
R.J. Curry, W.P. Gillin, J. Clarkson & D.N. Batchelder, “Morphological study of aluminum tris(8-hydroxyquinoline) thin films using infrared and Raman spectroscopy”, J. Appl. Phys., 92 (4), 1902-1905, 2002.
Evidence for electrophilic catalysis in the 4 chlorobenzoyl-co a dehalogenase...John Clarkson
K.L. Taylor, R-Q. Liu, P-H. Liang, J. Price, D. Dunaway-Mariano, P.J. Tonge, J. Clarkson & P.R. Carey, “Evidence for Electrophilic Catalysis in the 4-Chlorobenzoyl-CoA Dehalogenase Reaction: UV, Raman, and 13C-NMR Spectral Studies of Dehalogenase Complexes of Benzoyl-CoA Adducts”, Biochemistry, 34, 13881-13888, 1995.
Comparison of the structures and vibrational modes of carboxybiotin and n car...John Clarkson
J. Clarkson & P.R. Carey, "Comparison of the Structures and Vibrational Modes of Carboxybiotin and N-Carboxy-2-imidazolidone" J. Phys. Chem. A, 103, 2851-2856, 1999.
Characterization of the surface of a citrate reduced colloid optimized for us...John Clarkson
C.H. Munro, W.E. Smith, M. Garner, J. Clarkson & P.C. White, “Characterization of the Surface of a Citrate-Reduced Colloid Optimized for Use as a Substrate for Surface-Enhanced Resonance Raman Scattering” Langmuir, 11, 3712-3720, 1995.
Slide 1: Title Slide
Extrachromosomal Inheritance
Slide 2: Introduction to Extrachromosomal Inheritance
Definition: Extrachromosomal inheritance refers to the transmission of genetic material that is not found within the nucleus.
Key Components: Involves genes located in mitochondria, chloroplasts, and plasmids.
Slide 3: Mitochondrial Inheritance
Mitochondria: Organelles responsible for energy production.
Mitochondrial DNA (mtDNA): Circular DNA molecule found in mitochondria.
Inheritance Pattern: Maternally inherited, meaning it is passed from mothers to all their offspring.
Diseases: Examples include Leber’s hereditary optic neuropathy (LHON) and mitochondrial myopathy.
Slide 4: Chloroplast Inheritance
Chloroplasts: Organelles responsible for photosynthesis in plants.
Chloroplast DNA (cpDNA): Circular DNA molecule found in chloroplasts.
Inheritance Pattern: Often maternally inherited in most plants, but can vary in some species.
Examples: Variegation in plants, where leaf color patterns are determined by chloroplast DNA.
Slide 5: Plasmid Inheritance
Plasmids: Small, circular DNA molecules found in bacteria and some eukaryotes.
Features: Can carry antibiotic resistance genes and can be transferred between cells through processes like conjugation.
Significance: Important in biotechnology for gene cloning and genetic engineering.
Slide 6: Mechanisms of Extrachromosomal Inheritance
Non-Mendelian Patterns: Do not follow Mendel’s laws of inheritance.
Cytoplasmic Segregation: During cell division, organelles like mitochondria and chloroplasts are randomly distributed to daughter cells.
Heteroplasmy: Presence of more than one type of organellar genome within a cell, leading to variation in expression.
Slide 7: Examples of Extrachromosomal Inheritance
Four O’clock Plant (Mirabilis jalapa): Shows variegated leaves due to different cpDNA in leaf cells.
Petite Mutants in Yeast: Result from mutations in mitochondrial DNA affecting respiration.
Slide 8: Importance of Extrachromosomal Inheritance
Evolution: Provides insight into the evolution of eukaryotic cells.
Medicine: Understanding mitochondrial inheritance helps in diagnosing and treating mitochondrial diseases.
Agriculture: Chloroplast inheritance can be used in plant breeding and genetic modification.
Slide 9: Recent Research and Advances
Gene Editing: Techniques like CRISPR-Cas9 are being used to edit mitochondrial and chloroplast DNA.
Therapies: Development of mitochondrial replacement therapy (MRT) for preventing mitochondrial diseases.
Slide 10: Conclusion
Summary: Extrachromosomal inheritance involves the transmission of genetic material outside the nucleus and plays a crucial role in genetics, medicine, and biotechnology.
Future Directions: Continued research and technological advancements hold promise for new treatments and applications.
Slide 11: Questions and Discussion
Invite Audience: Open the floor for any questions or further discussion on the topic.
Richard's entangled aventures in wonderlandRichard Gill
Since the loophole-free Bell experiments of 2020 and the Nobel prizes in physics of 2022, critics of Bell's work have retreated to the fortress of super-determinism. Now, super-determinism is a derogatory word - it just means "determinism". Palmer, Hance and Hossenfelder argue that quantum mechanics and determinism are not incompatible, using a sophisticated mathematical construction based on a subtle thinning of allowed states and measurements in quantum mechanics, such that what is left appears to make Bell's argument fail, without altering the empirical predictions of quantum mechanics. I think however that it is a smoke screen, and the slogan "lost in math" comes to my mind. I will discuss some other recent disproofs of Bell's theorem using the language of causality based on causal graphs. Causal thinking is also central to law and justice. I will mention surprising connections to my work on serial killer nurse cases, in particular the Dutch case of Lucia de Berk and the current UK case of Lucy Letby.
Nutraceutical market, scope and growth: Herbal drug technologyLokesh Patil
As consumer awareness of health and wellness rises, the nutraceutical market—which includes goods like functional meals, drinks, and dietary supplements that provide health advantages beyond basic nutrition—is growing significantly. As healthcare expenses rise, the population ages, and people want natural and preventative health solutions more and more, this industry is increasing quickly. Further driving market expansion are product formulation innovations and the use of cutting-edge technology for customized nutrition. With its worldwide reach, the nutraceutical industry is expected to keep growing and provide significant chances for research and investment in a number of categories, including vitamins, minerals, probiotics, and herbal supplements.
This presentation explores a brief idea about the structural and functional attributes of nucleotides, the structure and function of genetic materials along with the impact of UV rays and pH upon them.
What is greenhouse gasses and how many gasses are there to affect the Earth.moosaasad1975
What are greenhouse gasses how they affect the earth and its environment what is the future of the environment and earth how the weather and the climate effects.
Seminar of U.V. Spectroscopy by SAMIR PANDASAMIR PANDA
Spectroscopy is a branch of science dealing the study of interaction of electromagnetic radiation with matter.
Ultraviolet-visible spectroscopy refers to absorption spectroscopy or reflect spectroscopy in the UV-VIS spectral region.
Ultraviolet-visible spectroscopy is an analytical method that can measure the amount of light received by the analyte.
Professional air quality monitoring systems provide immediate, on-site data for analysis, compliance, and decision-making.
Monitor common gases, weather parameters, particulates.
This pdf is about the Schizophrenia.
For more details visit on YouTube; @SELF-EXPLANATORY;
https://www.youtube.com/channel/UCAiarMZDNhe1A3Rnpr_WkzA/videos
Thanks...!
Deep Behavioral Phenotyping in Systems Neuroscience for Functional Atlasing a...Ana Luísa Pinho
Functional Magnetic Resonance Imaging (fMRI) provides means to characterize brain activations in response to behavior. However, cognitive neuroscience has been limited to group-level effects referring to the performance of specific tasks. To obtain the functional profile of elementary cognitive mechanisms, the combination of brain responses to many tasks is required. Yet, to date, both structural atlases and parcellation-based activations do not fully account for cognitive function and still present several limitations. Further, they do not adapt overall to individual characteristics. In this talk, I will give an account of deep-behavioral phenotyping strategies, namely data-driven methods in large task-fMRI datasets, to optimize functional brain-data collection and improve inference of effects-of-interest related to mental processes. Key to this approach is the employment of fast multi-functional paradigms rich on features that can be well parametrized and, consequently, facilitate the creation of psycho-physiological constructs to be modelled with imaging data. Particular emphasis will be given to music stimuli when studying high-order cognitive mechanisms, due to their ecological nature and quality to enable complex behavior compounded by discrete entities. I will also discuss how deep-behavioral phenotyping and individualized models applied to neuroimaging data can better account for the subject-specific organization of domain-general cognitive systems in the human brain. Finally, the accumulation of functional brain signatures brings the possibility to clarify relationships among tasks and create a univocal link between brain systems and mental functions through: (1) the development of ontologies proposing an organization of cognitive processes; and (2) brain-network taxonomies describing functional specialization. To this end, tools to improve commensurability in cognitive science are necessary, such as public repositories, ontology-based platforms and automated meta-analysis tools. I will thus discuss some brain-atlasing resources currently under development, and their applicability in cognitive as well as clinical neuroscience.
2. DeCipher Pte Ltd, a company which offers consultancy services to determine how to tackle problems caused by
fraudulent fuel marking with expertise in design, implementation and operation of fuel marking systems were aware that
these methods of detection were not entirely suitable since, as discussed later, they are unable to meet all the
performance criteria required. About three years ago the company became interested in a novel SERS method proposed
by Peter White after he had been able to devise a method for producing a very stable and reproducible silver colloid1,2
,
critical for any successful commercial SERS application. This SERS method when used in conjunction with a portable
Raman instrument, developed in partnership with Ocean Optics, has since proved to be very successful in all aspects of
fuel fraud detection. Having demonstrated the advantages of this SERS method over other detection methods, it has now
been chosen and implemented by several countries for the detection of fraud in their fuel control programs. Interestingly,
although the SERS detection and its potential were recognized over forty years ago, this is believed to be the first major
commercial and forensic application of this detection technique.
This presentation covers the development of the SERS system, including the portable Raman instrument and suitable
markers. Results from field trials are presented, together with examples of multiple marker detection and identification of
the illegal practices of fuel adulteration and laundering. Due to proprietary and contractual reasons some details about the
SERS reagents, the identity of the markers and information related to the marking protocols used in the field will not be
divulged. However, the advantages of this SERS method over the more traditional detection methods will be presented.
Finally, some preliminary studies using solid state SERS substrates as an alternative to colloidal silver for producing the
surface enhancement effects are also disclosed.
2. THE SERS METHOD
2.1 Development of the SERS system
The surface enhancing effect of silver and the resulting increase in sensitivity of Raman signals by up to six orders of
magnitude was identified by Fleischmann et.al, in 19743
. When possible to use a laser excitation wavelength close to the
max of the analyte (resonance Raman spectroscopy) and combined with this surface enhancement effect (surface
enhanced resonance Raman scattering (SERRS) spectroscopy) an overall increase in sensitivity of between ten and
fourteen orders of magnitude can be achieved, thus making it one of the most sensitive detection techniques. With the
additional advantages of providing molecular information, a high degree of selectivity and ability to measure analytes in
either aqueous or organic solutions, SERS was considered an ideal detection technique with many potential applications.
Many of these applications used a silver colloid as the SERS substrate and one of the first forensic applications of SERS
for the detection of trace levels of colorants was reported by White et.al4
at a SPIE conference in 1998. However, as with
many other applications, commercialization was hindered due to the lack of a method to produce a silver colloid that
could meet the requirements for SERS spectroscopy. A summary of a SERS spectroscopists meeting reported by Natan5
in 2006 specified the requirements for a suitable substrate and these included acceptable shelf-life, good batch to batch
reproducibility, low cost and a high enhancement factor.
These problems with production of a suitable silver colloid were overcome when in 2009 White and Hjortkjaer
developed and patented1
a method which produced a stable aqueous silver colloid solution that could meet and in most
instances exceeded all the required specifications. Having achieved this goal Peter White then proposed and showed,
amongst other ideas, the use of this colloid in a novel rapid single tube SERS procedure for the detection and
identification of marker(s) at low ppb levels in less than 1 ml of fuel. This was the start of the journey and with
DeCipher’s interest, expertise and development work their efforts finally resulted in introducing SERS spectroscopy as a
viable method for the detection and monitoring of the fraudulent use of fuels.
The single tube analytical method proposed was found to be a robust, reliable and quick procedure that can be used in the
field, even by operatives who had no previous scientific experience. The concept behind the use of single tube procedure
was based on the knowledge that the negatively charged silver colloidal particles in aqueous solution should aid the
extraction of any marker(s) from a fuel sample. Furthermore, when this procedure is performed in a glass vial, a SERS
spectrum of the marker(s) present in the aqueous phase can be achieved without any further manipulation of the sample.
Typically, a SERS spectrum of a marker present in a fuel sample is prepared for analysis as follows. Silver colloid
solution diluted with water (500 µl; colloid/water 30:70) is added to a 1.0 ml screw-capped glass vial which contains an
aliquot (500 µl) of the marked fuel. After capping the vial and vortex mixing the contents for 3 x 3 seconds, the sodium
chloride aggregating reagent solution (40 µl; 0.175M) is added, the vial capped and inverted twice to mix the
Proc. of SPIE Vol. 8710 87100G-2
4. Being stable in the fuel and carrier solvent.
Having specific detection characteristics with no false positives.
Having no effect on the fuel.
Being detected by a simple and fast test procedure with simple instrumentation.
Being detectable after attempts to laundering with acid, alkali or common absorbents.
Being detectable in a small volume of fuel to reduce volume of waste material.
Exhibiting a low level of degradation in sunlight.
Since many thousands of litres of fuels may require marking in a fuel control program, cost and the logistics of marking
are major issues. It is not only the cost of the marker that has to be considered but also the cost and volume of carrier
solvents used. Hence, an important consideration is the solubility of the marker in the carrier solvent. If for example a
marker concentration of typically 100ppb is required, then 10mls of a 1% marker concentrate in the carrier solvent would
be needed to disperse the solution into 1000 litres of fuel. In a fuel program the marker can be introduced into and
monitored at any point in the fuel supply chain with the marking of fuels being done either manually or by automatic
injectors.
As identified previously, the silver colloid particles are negatively charged and to achieve the strongest surface
enhancement effect the analyte i.e., marker in this case, must be in very close proximity to the silver surface. It is for this
reason why the markers used are predominantly cationic as these are attracted to the silver surface. This does to some
extent limit the choice of markers, however this has not been a problem as from extensive testing of over two hundred
potential markers a significant number have been identified that can meet the above specifications. Ideally, it is
preferable that many of these markers also display a max which is close to the laser excitation wavelength in order to
benefit from the additional sensitivity gained through the resonance effect.
In a fuel marking program more than one marker may be needed. One example is the requirement to be able to
differentiate between the sources of a fuel. This is essential if for example a road fuel is subsidized at a different rate to
an industrial fuel. More than one marker is also required by a country if they want to mark different fuels such as
gasoline, diesel, kerosene or biofuels, or to identify different grades of a fuel or regional malpractice. With this need to
detect, identify and quantify multiple markers in the field, this limits severely the number of analytical methods that can
be used. A major advantage of DeCipher’s SERS system is that multiple marker detection can be achieved in a single
analysis since in a spectrum obtained from a marked fuel it is possible to identify the spectrum of each marker and also
quantify the amount of each marker present.
3. SERS DETECTION OF FUEL FRAUD
3.1 Pilot studies
Within six months of proof of concept, the SERS system was developed and demonstrated very successfully in several
pilot studies carried out in a number of Asian countries. One of these was in a country where an existing diesel marking
system was already in operation. Results from samples analyzed using the existing system could therefore be compared
directly with those obtained from the SERS system. Of the five hundred samples analyzed it was possible to identify the
marker in every sample and no false positives were obtained. Furthermore, the operatives who used both detection
systems found the SERS method to be cleaner, faster, provided a permanent record of the data and only wasted 0.5 ml of
the fuel.
3.2 Application in the field
The success of these pilot studies and confirmation that the system was both robust and reliable, resulted in DeCipher
quickly gaining a number of major contracts for the marking of fuels. Subsequently, operation of the SERS system in the
field has provided customers with evidence of fuel fraud taking place in their countries. With DeCipher’s own unique
multi-marking scheme being used for marking diesel, gasoline, kerosene and biofuels and also different grades of these
fuels, cases of fuel fraud have been confirmed, successfully prosecuted and saving governments considerable losses in
revenue. It has also been observed that by introducing a successful fuel control program this deters fuel fraud and hence
loss of revenue.
Proc. of SPIE Vol. 8710 87100G-4
5. 2000 -
1500 -
>,...
c 1000
0
c
INDUSTRIAL DIESEL - Marker X
e
I
V
500 W_ L__
0
200 600 1000 1400 1800
Wavenumbers (cm"')
3000
2500
>, 2000
c 1500
ç 1000
500
0
200
AUTOMOTIVE DIESEL - Marker Y
600 1000 1400 1800
Wavenumbers (cm')
MIXED DIESELS - Markers X and Y
2500 -
2000 -
200 600 1000 1400 1800
Wavenumbers (cm'')
As explained earlier, more than one marker is required if wanting to differentiate between different fuels or grades of
fuels. An example of the latter is required when one grade of a fuel is taxed or subsidized at a different rate to another
grade. Hence when fuel stations are suspected of selling a lower grade of gasoline from pumps which should be
delivering premium grade gasoline, marking each grade of fuel with a different marker will confirm if any malpractice is
taking place. Another scenario where multiple markers are used in some countries is when industrial diesel is taxed or
subsidized at a different rate for automotive diesel. As illustrated in Figure 2, by marking the industrial diesel with one
marker (Marker X) and the automobile diesel with another (Marker Y), then by monitoring samples of diesel in
automobile fuel tanks, the presence of Marker X or both markers confirms the fraudulent use of the industrial diesel.
Figure 2. An example showing the advantage of being able to identify more than one marker in a single SERS analysis.
The spectra obtained shows that sample taken from an automobile tank contains two markers and is a mixture of
industrial diesel which contains Marker X and an automotive diesel which contains Marker Y
This ability to detect and quantify the individual markers in a mixture of markers in single analysis and in the field, has
been recognized as a major advantage of the SERS detection method over other analytical methods used previously and
why it is being selected for fuel monitoring programs.
Detection of fuel adulteration is often a requirement of some fuel control programs, especially if a subsidized fuel is
being used to dilute a non subsidized fuel. An example encountered is where kerosene, a subsidized fuel, is used to dilute
highly taxed and unsubsidized diesel. To detect this malpractice then either fuel could be marked or alternatively both
are marked with a different marker. In the example shown in Figure 3 the kerosene had been marked at a level 200pb and
detected in a sample of unmarked diesel thus showing the diesel had been diluted with kerosene.
Proc. of SPIE Vol. 8710 87100G-5
7. With demands for more complex fuel monitoring programs there is a greater need for systems that can detect and
quantify multiple markers with portable instrument based methods that can be used in the field. Instrument, operating,
marker and consumable costs, low detection limits, and good selectivity are also very important criteria when a country
is selecting a method. From the results presented above and the comments in Table 1, it is possible to see the advantages
gained in using this new SERS detection method and why this method is being selected and used.
4. SOLID-STATE SERS SUBSTRATES
Solid-state SERS substrates used as dipsticks have been explored as a method of monitoring marker in fuels. Table 1 lists
advantages and disadvantages of colloidal substrates compared to solid-state substrates for measuring fuel markers.
Currently, commercially available solid state SERS substrates are prohibitively expensive and some have relatively low
enhancement factors. A recent review of low cost SERS substrates show these can be produced using much cheaper and
simpler methods6
. The advantages of solid state substrates include, simplicity of use compared to colloid substrates and a
direct measurement of markers in fuel. DeCipher has obtained promising results from a low cost, solid state SERS
substrate and together with Ocean Optics are in early stage development of this substrate, instrumentation and marker
chemistry towards a solid-state SERS fuel marker product. This development will increase the choice of fuel markers.
Table 2. Comparison of the advantages and disadvantages of colloidal and solid-state SERS substrates for measuring fuel
markers.
SERS
SUBSTRATE
ADVANTAGES DISADVANTAGES
COLLOID
• There is a proven Working System for
fuels.
• Quick results, < 3 mins.
• Quantitative.
• Inexpensive.
• Reproducible.
• Long shelf-life time.
• SERS observed for a limited time due to
aggregation.
• Not a direct measurement and reagents need to
be added to develop SERS.
SOLID
STATE
• Simple measurement using a “dip-stick”.
• Markers measured directly in fuel.
• SERS can be measured days after initial
measurement.
• New substrates reported to have high
enhancement factors, comparable to colloid,
enabling low detection limits
• Method can be automated for bulk laboratory
analysis.
• No Working System in the market suitable
for detection of markers in fuels.
• Not known whether the sensitivity of solid-
state substrates match colloidal systems.
• SERS signal may take a relatively long time to
develop e.g., > 10 mins.
• Reproducibility and shelf-life time unknown.
5. CONCLUSIONS
A SERS detection method using a portable instrument has been successfully developed, implemented in the field and
shown to have considerable advantages over other methods currently used for the detection of fuel fraud. A novel single
tube sample preparation scheme which uses the properties of a stable silver colloid provides an overall analysis time of
typically five minutes.
Both qualitative and quantitative analyses of markers in all types of fuel can be obtained when present at levels down to
1-10 ppb thus highlighting the sensitivity of the detection system and hence making it possible to detect the malpractices
of fuel adulteration and laundering. One of the other major advantages of this technique is the high degree of selectivity
that can be achieved and this enables identification and the quantification of multiple markers in fuels in a single
analysis.
Proc. of SPIE Vol. 8710 87100G-7
8. Since adopting this SERS monitoring system as the lead technology for fuel control programs in several countries, the
results obtained have provided evidence which has resulted in successful prosecutions. Interestingly, this is believed to
be the first major commercial and forensic application of SERS and only made possible due to a method developed
recently for production of a stable and reproducible silver colloid, an essential component for any commercial
application of SERS spectroscopy. More recently the company has started to evaluate the potential of using solid-state
SERS substrates as these should be able to extend the range of markers that can be used.
Finally, this success cannot be attributed solely to development and use of this novel detection method. DeCipher’s
expertise in determining how to tackle problems in monitoring fuel fraud, the marking of fuels and the design,
implementation and operation of fuel marking systems are just as important. Furthermore, since the company’s senior
personnel are responsible for the infrastructure and sub-contracting of operational manpower, DeCipher is also able to
provide an integrated operations system of controlled marking, linking terminal deliveries to retail site receipts and
managing an active surveillance/testing program.
The silver colloid patent referred to in this paper is owned by the University of Lincoln, UK.
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