Replicating the Grading of oils with UV Fluorescence on other cameras pt 1

by mathew | over 10 years ago | 4 | 0

What I want to do

replicate the results of my previous note using different other cameras. I want to know if the shift in the location of a spectra's peak from blue-green as a measure a series of heavy-to-light oils is reproducible. I took the spectra in the previous research note with a Syba camera that shipped in our first and second Desktop spectrometry kits, Here I compare to the Sanm camera found in the current Desktop Spectrometer and the infragram Webcam.

I want to see a replication of this pattern, where heavier = bluer. preferably at the same location.

• 5W-30 has a peak at 444nm
• 20W-50 at 436-8nm
• 80W-90 at 432-435nm

My attempt and results

I started measuring the styrene cuvettes I'd used in my previous trials, but some of them were melting (yes, melting) from contact with the oils and especially the diesel.

The Infragram Webcam has been deconstructed, and its blue filter removed, and the surface of the CCD cleaned off with denatured alcohol. Its focal length is set to 9." It is quite a bit more sensitive than the syba cam, and produces bright spectra. That becomes an issue. It could perhaps be attenuated with an optically-printed slit. It seemed like I got a lot of "blown out" spectra.

I tried some spectra through a polarized grating to attenuate it. it seemed to match the dimmer spectra taken off-center from the fluorescing oil.

just looking at and trusting (becuase they look nice) the lower peaks, I'm not able to grade the oil:

I'm not really seeing a clear difference in the peaks between diesel and crude either:

Sanm cameras

the crude peaks, even the "clearest" looking ones between syba, sanm, and infragram cameras are all different.

comparing crude to diesel on each leads to differing conclusions. The infragram camera and sanm cam both have a bluer peak fro diesel than crude, the opposite of what I'd expect, and neither is in the same place.

Questions and next steps

testing all the other cameras I have here built into spectrometers.

Why I'm interested

Read more Follow

spectrometer fluorescence oil-testing-kit 405nm

Grading oils with UV fluorescence

by mathew | over 10 years ago | 5 | 1

What I want to do

I want to be able to grade oils from light to heavy. I'm going to use a means of UV Fluorescence with a 405nm laser pointer. I'll look at the emission spectra and see if I get a shift of the spectra's peak from green to blue as I move from light to heavy oils. My goal is to replicate a UV Fluorescence technique used in UV LIDAR research.

previously....

Also,

• Can I replicate the location of emission spectra from a 337nm Nitrogen laser?
• Can I see peak transition in oil grades from light to heavy oils?
• what about motor oils?
• can I distinguish diesel from crude?

  My attempt and results

the setup

The target oils were things I could find nearby-- a few grades of motor oil, some gear oil, crude oil from North Dakota, and deisel fuel. The idea is lighter oils should have a greener peak, and heavier ones a blue peak.

I started with a rectangular cuvette that @warren sent me and filled it with 1ml of mineral oil.

I determined concentration by adding single drops of the target oils.

results

do the different solutions have the same peaks?

These different concentration spectra seem to have similar peaks between 1-3nm apart.

the higher concentrations gave me a spectra with a clear cutoff, as if I saturated the image. Is this correct? I want to trust the lower intensity spectra more. should I?

Do I see a shift from green to blue as the oil gets lighter?

Motor Oils

Will the heavier 80W-90 have a more blue peak than the 20W-50?

• 5W-30 has a peak at 444nm
• 20W-50 at 436-8nm
• 80W-90 at 432-435nm

Well, they seem to roughly follow the blue shift pattern

2-cycle is unlabeled, and so its grade isn't known. but it has a peak at 445

Crude Oil & Diesel

I see 10nm between North Dakota crude and Diesel. The North Dakota crude is dissolved 1 droplet in 2ml of mineral oil, the diesel is undiluted, I am comparing them at similar fluorescences, not concentrations.

Is that good? I'm not really sure. it seems like less of a gap than between different grades of crude.

Questions and next steps

I need people to replicate this experiment.

Hypotheses: 1) by varying the concentration of the target oil to get a lower, less blown out spectrum. true or not?

Why I'm interested

To distinguish crude oil from fuel oil, and ultimately from organic naturally occuring substances that also fluoresce, such as decaying organic matter (DOM) or humic acid.

Read more Follow

spectrometer laser fluorescence crude

Laser Pointers and the LIF Literature

by mathew | over 10 years ago | 1 | 1

*LIF stands for Laser Induced Fluorescence.

What I want to do

I want to answer three questions through reviewing peer-reviewed journal articles, with short answers below, and add this information to the oil testing kit literature review:

• What equipment in the literature is the oil testing kit most like?
  • answer: airborne UV fluorescence LIDAR.
• What results does the equipment in the literature produce?
  • answer: distinguishing crude oil into 3-8 grades (Hengstermann 1992), distinguishing between humic acid and natural oils and crude.
• Is our equipment similar enough to produce the same results,
  • answer: probably.
  • Specifically, are the differences in laser frequency between our laser pointer and the gas lasers in the literature going to be a problem?
    • answer: probably not.

What Equipment in the literature is most similar to the oil testing kit?

What our equipment isn't able to do

Most of the contemporary articles in the fluorescence literature (1990-today) focus on two methods, Synchronous Scanning Fluorescence and fluorescent decay. Synchronous Scanning Fluorescence illuminates a sample with a precise light source from a monochronometer (essentially a reverse spectrometer that allows the selection of just a single color.) and takes a series of measurements at regular intervals, stepping up through the spectrum while also measuring fluorescence at an offset point, 20nm higher, for instance. Fluorescent decay is the time it takes a material to stop fluorescing after the light source is removed. This is usually measured in nanoseconds and outside the capability of our spectrometer. Both techniques can be combined to generate a record of decay across a synchronous scan.

Neither of these methods are within the capabilities of our spectrometer, however there may be techniques similar to synchronous scanning we can empoly, which I'll cover in a followup note.

What our equipment is is similar to

@warren found an article by O’neil et al, 1980 that discussed measuring fluorescence from an airborne LIDAR (Light Induced Detection and Ranging) system flying over oceanic oil spills. Essentially a laser and a telescope pointing at the same laser point. An article by Moise et al that also mentioned fluorescence in a lab. These lab tests were a verification of a LIDAR flourescence system, and this is the equipment our device is most similar too, since it measures just the fluorescence profile of the oil, without either a Synchronous Scanning Fluorescence or the fluorescence decay.

These airborne LIDAR systems were developed during the seventies and eighties. I was able to find additional articles about this technique.

Angle of Laser to Spectrometer

O'Neil's team used a device of this design (O'Neil 865):

The most prominent difference between this and the Public Lab oil testing kit is that a one-way mirror is used to project the laser downwards along the same path as the spectrometer is pointed. The fluorescence measured is therefore reflected back 180 degrees instead of 90, as in the perpendicular arrangement of our oil testing kit.

This may not be a big deal, as other airborne systems of a similar vintage often put the laser at something less than 180 degrees (Bristow 107):

The different angle may effect our ability to use the backscatter of the laser to measure fluorescence efficiency, which may improve our data, if we can measure it.

Intensity and fluorescence efficiency

As noted by Hengstermann: "all spectra have been normalized to unit total fluorescence intensity observed in the entire spectral range from 311 to 700n. This has the advantage that the detector system must not be calibrated in absolute units. But the classification of curse does only consider the shape of the spectrum and makes no use of absolute fluorescence intensity."

So we don't need intensity calibrated (which we don't have right now) to get good results , but we may need a linear response to understand the fluorescence efficiency of our measurements... unless normalization of spectra across recorded fluorescences/concentrations is enough, which it may be, as @warren pointed out in his summary of Patsayeva, S., et al's research

Laser wavelength

We are using a 405nm laser, while the majority of laser induced fluorescence experiments have been conducted with 337nm nitrogen lasers, and some with XeCl lasers (308nm), Nd:YAG Lasers (355nm) (Patsayeva et al). Will this dramatically change our results?

This quote from Johnson et. al is echoed elsewhere, but says it the best:

"For the large organic mole­cules of interest here, the relative shape of the fluorescence emission spectrum is independent of the excita­tion wavelength; conversely, the relative shape of the excitation spectrum is independent of the wavelength at which the emission is monitored. If the absorbance of the sample is low enough and the spectral variation of the excitation source is properly ac­counted for, the excitation spectrum will closely resemble the absorption spectrum."

So we are likely to get similar fluorescence even though we've chosen a higher wavelength. That said we'll probably miss some components. 11 of the 16 polyaromatic hydrocarbons (PAHs) classified as priority pollutants by the EPA have maximum fluorescence peaks below 405nm; Naphthalene, Acenaphthene, Fluorene, Phenanthrene Pyrene, Anthracene, Benzo[k]fluoranthene, Benzo[a]pyrene, Dibenz[a,h]anthracene Chrysene, Benz[a]anthracene. from Table I, Kumke et al.

While this may seem problematic, the overall peak fluorescence of crude oils is above 405nm (equipment in the literature, below).

Conclusions on replication of LIDAR fluorescence devices capabilities

So it seems like we should be able to reproduce the results of early eighties gross fluorescence systems without further improvements in calibration, so long as we can get bright enough spectra. nice!

What results does the equipment in the literature produce?

It is repeatedly pointed out how difficult it is to actually isolate a specific component of a hydrocarbon mixture, and how fluorescence alone can't do it:

Bristow: "Unfortunately, long wave UV excitation of crude oxls produces visible fluorescence emission spectra which are broad and featureless and as such do not provide for unambiguous oil spill identification or char- acterization."

Johnson et al: "analysis of a sin­gle component will be subject to inter­ferences from other fluorescent components, and that the simultaneous analysis of several components will be frustrated by spectral overlaps."

Kumke: "The detection of PAC in the environment is usually accompanied by the necessity of multicomponent analysis because most real contaminations consist of complex mixtures, such as, e.g., mineral oils or oil products. "

However, Hengstermann & Reuter point out:

"fluorescence spectra of different oils show characteristic variabilities of their intensity and spectral shape, which allow one to differentiate mineral oils according to the main oil classes (4-11) Examples of fluorescence spectra measured on samples of North Sea crude oil are shwn in Fig. 2. In the same way, these crude oils can be discriminated from heavy fuel, and from less harmful substances like fish oil or vegetable oil, Fig. 3, which can also be responsible for surface slicks resembling those consisting of mineral oil...

Recording the shape of the spectrum obtained at those parts of an oil spill where the optically thick parts of oil can be located provides a method for estimating the oil type. With UV excitation, light oils are characterized by strong fluorescence at blue wavelengths, and the fluorescence yield of heavy oils is markedly re- duced with maximum values in the green part of the spectrum."

This is good news. it means the green-blue shift for determining the grade of crude that @warren discovered in Patsayeva, S., et al is possible without measuring decay or other more sophisticated methods. Also, Hoge et al point out that the peak of Venesuela heavy crude is 490nm, while that of light Murban crude is 505nm (table L). So it appears that this blue/green shift in the peak is well aboce 405nm and won't substantially effect our ability to detect it. and as Hengstermann points out in 1992, we should be able to determine at least 3 and perhaps as many as 8 grades of crude.

Questions and next steps

Is the 90 degree measurement of fluorescence to the laser an issue for determining the fluorescence efficiency? Or better-- is normalization of the peaks of spectra enough to compare different measurements without accounting for fluorescence efficiency?

Citations

1. 1. Johnson,1 J. B. Callis,2 and G. D. Christian1, Rapid Scanning Fluorescence Spectroscopy, Anal. Chem. VOL. 49 NO, 747 A. 8 JULY 1977.PAYWALL

M P F. BRISTOW, Airborne Monitoring of Surface Water Pollutants by Fluorescence Spectroscopy, REMOTE SENSING OF ENVIRONMENT 7,105-127, 1978. PAYWALL

O’neil, R. A., L. Buja-Bijunas, and D. M. Rayner. "Field performance of a laser fluorosensor for the detection of oil spills." Applied Optics 19.6 (1980): 863-870. (Google Scholar) - summary

1. 1. Hoge and R. N. Swift, Oil film thickness measurement using airborne laser-induced water Raman backscatter, APPLIED OPTICS Vol. 19, No. 19 3269, 1 October 1980.PAYWALL

Theo Hengstermann and Rainer Reuter, Lidar fluorosensing of mineral oil spills on the sea surface, APPLIED OPTICS Vol. 29, No. 22, 1 August 1990.

Paolo Camagni et. al, Fluorescence response of mineral oils: spectral yield vs absorption and decay time. APPLIED OPTICS Vol. 30, No., 1 January 1991.

T. Hengstermann and R. Reuter, Laser Remote Sensing of Pollution of the Sea: a Quantitative Approach, EARSeL Advances in Remote Sensing, Vol. 1, No. 2-II, 1992.

Allen R. Muroski, Karl S. Booksh,† and M. L. Myrick*, Single-Measurement Excitation/Emission Matrix Spectrofluorometer for Determination of Hydrocarbons in Ocean Water. 1. Instrumentation and Background Correction, Anal. Chem. 68, 3534-3538, 1996.

Patsayeva, S., et al. "Laser spectroscopy of mineral oils on the water surface." EARSeL eProceedings 1.1 (2000): 106-114. (PDF, Google Scholar) - summary

Moise, N., Aurelia Vasile, and Mihail-Lucian Pascu. "Measuring of water and soil contamination with oil components using laser-induced fluorescence transmitted through optical fibers." ROMOPTP'94: 4th Conference on Optics. International Society for Optics and Photonics, 1995. (Google Scholar) - summary

Bublitz, J., et al. "Fiber-optic laser-induced fluorescence probe for the detection of environmental pollutants." Applied optics 34.18 (1995): 3223-3233. (Google Scholar) - summary

Kumke, M. U., H-G. Löhmannsröben, and Th Roch. "Fluorescence spectroscopy of polynuclear aromatic compounds in environmental monitoring." Journal of Fluorescence 5.2 (1995): 139-152. (Google Scholar) - summary

Bonus Jargon!

Just look at all these acronyms. Look at them! From Kumke, et al.

"Abbreviations used: DF, delayed fluorescence; EEM, excitation- emission matrix; EPA, U.S. Environmental Protection Agency; FIA, flow injection analysis; FOCS, fiber optical chemical sensors; FTIR, Fourier transform infrared; LAMMA, laser microprobe mass analysis; LIDAR, light-induced detection and ranging; LIF, laser-induced fluorescence; LOD, limit of detection; MALDI, matrix-assisted laser desorption/ionization; MPI, multiphoton ionization; OSA, optical spectrum analyzer; PAC, polynuclear aromatic compound; PAS, pho- toelectrical aerosol sensor; RAFA, rank annihilation factor analysis; RTP, room-temperature phosphorescence; SDW, soil dry weight; SERS, surface enhanced Raman spectroscopy; SIMS, secondary ion mass spectroscopy; SIT, silicon intensified target; TDGC/MS, thermal desorption-gas chromatography/mass spectrometry; TFA, total fluorescence analysis; THEES, total human environmental exposure study; TTA, triplet-triplet annihilation; UMC, uncorrected matrix correlation; WHO, World Health Organization."

Read more Follow

spectrometer uv laser fluorescence

Oil Terminal Monitoring - Newburgh (NY)

by joshuaflux | over 10 years ago | 2 | 3

photo credit Wigwam, from http://wigwameconomy.com/oil-terminal-across-from-beacon-seeks-expansion/

What I want to do

Monitor the Global Partners site along the Hudson River on the border of New Windsor and Newburgh where Bakken shale is currently being processed. Prevent this site from being expanded with boilers for processing Canadian Tar Sands.

Location and operation details

The parcel is just over the border of the Newburgh-New Windsor tax line, so that it is technically in New Windsor; however, this project is closer to more Newburgh residents than those from New Windsor. Newburgh (where I'm from) is a poverty-stricken City. A freight rail line runs here along the west side of the Hudson River, carrying Bakken crude oil from North Dakota. One or two highly explosive 100-car unit trains per day arrive, each carrying 30,000 gallons of oil. If given the opportunity to expand, it will double the Bakken processing and introduce tar sands processing by way of both rail and barge on the Hudson River!

Stakeholders

• Beacon's "node" center
• Newburgh's Quassaick Creek Alliance
• Riverkeeper
• Clearwater

My attempt and results

I want to set up community monitoring of this site to contribute to environmental justice advocacy.

Questions and next steps

• access issues with the actual parcel--there is fencing around three sides of the property, and you can only access it from the Hudson River. If you are on the river, you can get very close (within several feet).
• where will we show the data we create?

Why I'm interested

This is my hometown and I care about a healthy Hudson Valley.

Further background

link: http://wigwameconomy.com/oil-terminal-across-from-beacon-seeks-expansion

Read more Follow

new-york oil tar-sands bakken

North Brooklyn Boat Club reporting increased oil sightings

by liz | over 10 years ago | 2 | 1

What I want to do

Develop a sampling procedure for oil sheen on water to support groups such the North Brooklyn Boat Club who do environmental advocacy on Newtown Creek. Increasingly frequent incidents of "unknown petroleum" are being reported, read the article here: http://www.dnainfo.com/new-york/20140820/greenpoint/businesses-near-newtown-creek-eyed-after-series-of-oil-spills-state-says

My attempt and results

Matt Pendergraft suggested to collect samples of sheen by placing an absorbent material on the surface of the sheen. The pad can be 'wrung out" to reduce the amount of liquid being carried around (b/c any liquid sample would be mostly water). Once collected, fold the pad for transit in aluminum foil, then put in ziploc bag.

To process it, extract the oil with another hydrocarbon, then siphon off the oil which presumably has risen to the top of the water.

In terms of what actual material to use, try using the absorbent pads used for gas spills in the bottom of boat because they don't soak up water--they soak up gas/oil. These are sold in home depot, auto supply stores, boat stores.

Questions and next steps

I am planning to purchase a variety of motor oils and gasolines to test sample preparation and analysis with.

• will gasoline sheen evaporate away because it’s so volatile?

Why I'm interested

Oil and gas sheen on water is the most common question i get in the New York / New Jersey area (with particulate air pollution a close second). So far, we've developed a clear sampling procedure for sampling a solid Gulf-style tar ball, which fortunately are rarely seen in this region at this time. I am hoping to advance our ability to work with more diffuse samples such as oil sheen on water that are common in this region.

Read more Follow

new-york-city newtown-creek oil-spill oil

Using Gelatin Caps for oil fluorescence

by mathew | over 10 years ago | 19 | 3

What I want to do

see if we use gelatin caps as sample containers. They cost a few cents each, 100 for $5 at my local pharmacy. I picked up 25 each of sizes 4-00.

My attempt and results

The gel caps have a lensing effect because of the shape, it is more severe the bigger the gel cap. The smallest #4, which was only a little bigger than the laser beam was the easiest to make fluoresce. I filled them with olive oil for my tests.

I moved the slit to the outside of my conduit box so I could get my samples right up against it, and then made a little tube out of black aluminum foil to slide the gel caps in.

I also tried them sideways. Only the #4 worked sideways. by just holding it.

The two big curves fluorescing at 670nm are a glass jar (control) and the #4 gel cap. The other caps, probably from the lensing, didn't work as well. The #4 worked as well as a glass container with the laser aligned perfectly, very close to the glass and along the slit.

I also tried out one of the cuvettes Jeff sent me, but couldn't get the fluorescence to read at any angle.

Questions and next steps

The gel caps weren't too hard to fill, but I always got a little oil outside (I used a dropper). So its not super clean. They don't seem to leak though, however they are hard to label and easy to crush.

Why I'm interested.

at 5 cents they're cheap and work great and are easy to get. they don't need a big sample, but perhaps need a mixing container.

Read more Follow

spectrometer oil fluorescence cuvette