The Public Lab Oil Testing Kit is an attachment to Public Lab's v3.0 Desktop Spectrometer which holds a sample container and a laser.
##The Basic Spectrometer
Public Lab first began developing cheap spectrometers in the winter of 2010, after the Deepwater Horizon oil disaster in the Gulf of Mexico. Since then [we've made enormous progress](/wiki/spectrometer-history) and have [a variety of designs for less than $100](/wiki/spectrometer), but the OTK is based around the [USB webcam-based Desktop Spectrometry Kit v3.0](http://store.publiclab.org/products/desktop-spectrometry-kit-3-0) ([see plans here](/wiki/desktop-spectrometry-kit-3-0))
Of course, the plans for all of these are [on the Public Lab website](/wiki/spectrometer) and are open source hardware designs, so you can always make your own -- the kits are intended to help you get started.
##The Oil Testing Kit attachment
You'll also need a frame to hold your sample container and align a laser beam perpendicular to your spectrometer. For that, we've developed the Beta Oil Testing Kit, an add-on to the Desktop Spectrometer v3.0 pictured here, attached:
[](https://i.publiclab.org/system/images/photos/000/010/454/original/IMG_20150521_145931_2.jpg)
If you [join the Beta testing program](/wiki/oil-testing-kit-beta), you can then sign up for [the add-on "Beta" Oil Testing Kit](http://store.publiclab.org/products/spectrometry-sampling-kit) (see [parts list](#Parts+list) to assemble your own) in combination with the existing [Desktop Spectrometry Kit](http://store.publiclab.org/products/desktop-spectrometry-kit), which is what was used in the examples on this page.
##Assembly
See [this excellent research note](/notes/mathew/04-07-2015/assembling-the-oil-testing-kit-cuvette-frame
) for assembly instructions.
Additionally, we've added a light-blocking flap which reduces ambient light. This extra piece (source file here:
light-flap.svg
) fits into the OTK frame and can be held or taped shut while activating the laser:
[](https://i.publiclab.org/system/images/photos/000/011/021/original/IMG_20150803_133451_2.jpg)
[](https://i.publiclab.org/system/images/photos/000/011/024/original/IMG_20150803_133555_2.jpg)
[](https://i.publiclab.org/system/images/photos/000/011/026/original/IMG_20150803_133625_2.jpg)
****
#Parts list
_These are links to where you can buy parts to assemble your own oil testing kit_
##Sampling materials
Part | Est. price | Link
------------|-------------|-----------------
acrylic/PMMA cuvettes -- containers for your samples | $0.25 each | http://www.amazon.com/BrandTech-759086D-acrylic-Semi-Micro-Spectrophotometry/dp/B004WFD7RW/ (NOT polystyrene - they melt when filled with lighter petroleum!)
5oz mineral oil (baby oil -- the added fragrance doesn't fluoresce) | $3 | http://www.amazon.com/Johnson-Baby-Oil-Kids-Ounce/dp/B000GCJM06/
eyedropper | $6 for 100 | http://www.amazon.com/Plastic-Transfer-Pipettes-Gradulated-Pack/dp/B005IQTSE0/
cotton swabs | ~$3 for 500 | http://www.amazon.com/Q-tips-Cotton-Swabs-500-Count/dp/B00I6A69TM/
##Laser
* a 405nm blue/violet laser pen: [$3 from Alibaba](http://www.alibaba.com/product-gs/700677050/well_tested_405_nm_blue_laser.html), or for purchasing singles [here](http://www.ebay.com/itm/2in1-5mw-Blue-Violet-Purple-Laser-Pointer-Pen-With-Star-Cap-405nm-Best-Selling-/301258047058) Some people feel having the caps are useful for dispersing the laser when necessary so if you want more caps perhaps [this](http://www.ebay.com/itm/6-in-1-5mW-405nm-Violet-purple-Blue-Laser-Pointer-with-5-Patterns-Star-Caps-/371078275357) will be to your liking
##Frame
Download and cut out all the five pieces on dark, [card-stock weight paper such as this](http://www.neenahpaper.com/FinePaper/ROYALSUNDANCEPapers):
all-together-9-8.511.pdf
all-together-9-8.511-2.pdf
[](https://i.publiclab.org/system/images/photos/000/009/587/original/all-together8-laser.jpg)
###Light-blocking flap
light-flap.svg
****
###Alternative parts
We've tried many different bottles and parts; some are no longer available, or had shortcomings. But here's a list of links to things we've tried!
* Nail polish bottles, with built-in bottlecap-swabs. An all-in-one, one-use pre-filled with mineral oil! Maybe you break off the swab and throw it away, or maybe it doesn't matter.
* http://www.alibaba.com/product-detail/nail-polish-bottles_862081740.html?s=p
* http://www.alibaba.com/product-detail/10ml-empty-square-nail-polish-bottle_1042482910.html?s=p
* http://www.alibaba.com/product-detail/0-4oz-Art-Nail-Polish-Bottle_674230480.html
* http://www.ebottles.com/showbottles-bottle-1556-kw-ELIQUID_VIALS.htm
* http://www.ebottles.com/showbottles-bottle-1329-gclid-Cj0KEQjwopOeBRC1ndXgnuvx8JYBEiQAq4RPt_MBIoRstpRXJzK66iXV1lbaZ6J7TWOot8oR6wDas7QaAops8P8HAQ-kw-NAIL_POLISH_BOTTLES_WITH_BRUSHES___GLASS.htm
* http://www.freundcontainer.com/french-square-glass-bottles/p/v4225B01/
[](https://i.publiclab.org/system/images/photos/000/011/025/original/IMG_20150803_133625_2.jpg)