Monday, December 22, 2014

Separation of mercury from VOC’s and selective detection using gold film amalgamation and photoionization detection

Accepted for presentation at #ACSDenver 2015 on March 23, 2015:

PAPER ID: 2152487 
PAPER TITLE: “Separation of mercury from VOC’s and selective detection using gold film amalgamation and photoionization detection” 

DIVISION: [ANYL] Division of Analytical Chemistry

SYMPOSIUM: Advances in Analytical Separations 

Authors: J.N. Driscoll and J.L.Maclachlan, PID Analyzers, LLC Sandwich, MA USA

We used a sensitive but nonspecific photoionization detector (PID) with a 10.6 eV lamp to measure mercury that has an ionization potential of 10.43 eV. The PID responds to both mercury and VOC’s and the VOC’s have to be removed to make the technique specific for mercury. The chemistry of the gold/mercury amalgam makes this method specific for mercury and eliminates interference from VOC’s. This technique also concentrates the sample making the method sensitive to sub ppb levels. Mercury permeation tubes were used to generate levels from 0.02 to 1 ppm.

The method is applicable for both air and water samples. Air samples are collected and only the mercury is reacted with the gold surface. Any impurities are purged through, then the amalgam is heated to desorb the mercury which is measured by the detector. Water samples are analyzed using hydride generation with sodium borahydride to reduce the mercury salts to elemental mercury that is efficiently detected by the PID. The EPA MCL for mercury in drinking water is 2 ppb. The detection limit for Hg in water by hydride generation HGPID was 0.2 ppb.

See the rest of the Analytical Chemistry Division programming for ACSDenver 2015 here.

Tuesday, October 28, 2014

Wicked Sweet Science Cafe~It's how Cape Cod celebrated National Chemistry Week 2014

It was a perfect New England October Saturday for the Cape & Islands Boy Scouts Council of America to have their mostly outdoor Wicked Cool Autumn Welcome at BSA Camp Greenough in Yarmouthport, MA. 
This is the second  consecutive year that we have partnered with the Cape & Island Council of the Boy Scouts of America for their Wicked Cool Autumn Welcome which features a fall themed day of family fun: pumpkin carving, wood-working, fishing, archery and more. Last year and this year the and more was a science cafe in celebration of National Chemistry Week! We won a ChemLuminary Award from the American Chemical Society for our 2013 collaborative efforts. Above is the participation patch that was given to all 400 children in attendance. 
This is what the cafe part of a science cafe for kids looks like: cookies, hot chocolate and oranges. Since it was almost Halloween, we had Halloween themed cookies. Special thanks to Amy Zahn and her son for baking 30 dozen cookies for our science cafe!

My eldest daughter and I wearing our Science is Fun t-shirts working the ACS table. We had some leftover Wicked Cool Science Cafe glow sticks from last year. We'll definitely get more of these for next year because kids love glow sticks.

Volunteers from Green Briar Nature Center conducting chromatography experiments for the Cape Cod Science Cafe.

My daughter doing what she loves best. Being the "test kid" before all the other kids get there.

Candy chromatography with M&Ms

Originally they had planned to use the peanut butter ones, too. But since we all know that kids have a way of ingesting things they shouldn't (we were concerned about allergies) so they crossed it off  the sign and eliminated it from the experiment. 

My daughter wanted us to do a "guess how many candies are in the jar" since the 2014 National Chemistry  Week theme is Candy, the sweet side of chemistry. Her grandfather and organizing committee member, Jack Driscoll,  suggested that we make the kids calculate how many instead of guessing and that way we add a STEM component to it. Then our company, PID Analyzers, contributed four $10 gift certificates to the bookstore for correct answers that were drawn by the Wicked Cool Autumn Welcome Chairman at the spaghetti dinner that followed the event. If folks weren't attending the dinner, they were asked to write their phone number on the paper in addition to their full name.
So this table became dubbed "the math table". Some kids had trouble with the term "units", some kids had parents who didn't understand and/or couldn't explain it to their kid, most of the kids could do it once we told them that it was a math problem. All the kids were impressed with the prize. Wow! A $10 gift certificate to the bookstore! I actually had one kid say, "Math! I wanna do science. Where's the science?"

This was the view from the dining hall where the Science Cafe was held, This is where the pumpkin carving and face painting took place.

One of our organizing committee members, Eben Franks, and his wife, brought along their cider press. This was located outside the dining hall door overlooking the pumpkin carving with a view of the lake.

Saturday, October 11, 2014

Analysis of Natural Gas Composition and BTU Content from Fracking Operations

Accepted for presentation at Pittcon 2015
New Orleans, Louisiana
March 8-12 2015

Abstract Number: 1370 - 5
Session 1370 - Advances in Energy Research: From Unconventional Fuels to Solar Energy
Day and Time: Tuesday, March 10, 2015, 03:05 PM
Room 240

Significant shale deposits exist in 22 states including the Northeast states of Ohio, Pennsylvania, and New York Utah and Wyoming in the West; and gas-producing states such as Texas, Louisiana, Arkansas and Mississippi. The use of horizontal drilling and hydraulic fracking of shale has catapulted the US into the leading producer of natural gas in 2013.  Natural gas is bought or sold based on the quantity of energy delivered. The product of the concentration (determined by gas chromatography) and the heating value (BTU) determines the BTU content of the fuel. Although the natural gas from Marcelis shale is primarily methane, the composition can vary considerably from region to region

Shale gas streams can vary in composition from primarily CH4 to one that can contain heavier HC (to C6+) species. One does need flexibility in a GC and the GC301C with temperature programming does have it. The 301C has dual detectors (FID & TCD), packed and capillary column capability and temperature programming. It has an embedded PC and Windows 7.0 operating system with PeakWorks chromatography control software. It is a compact industrial gas chromatograph in a 19” rack mount or wall mount enclosure. Outputs include RS485, and 4-20 mA. It can be connected to the internet and can be controlled remotely.  For natural gas, the methane content can vary from about 85 to 98 mole %, ethane varies from 1-7%, propane from 0.1 to 6%, nitrogen 0.2 to 6%, carbon dioxide from 0.1 to 1% with the balance of C4 and C5 hydrocarbons at trace levels. The exact composition can significantly change the BTU content. Methods can be stored for different compositions and changed remotely for additional flexibility in fracking operations.

See presentation slides below.

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