Rapid Separations on a Portable GC with Resistively Heated Columns

Methodology:	Gas Chromatography
Application:	Environmental
Primary Focus:	Application
Title:	Rapid Separations on a Portable GC with Resistively Heated Columns
Keywords:	Detection Environmental Environmental Analysis Gas Chromatography

Assignment Status:	Assigned ORAL		Session Title:	Environmental Analysis: Pharmaceutical and Biologically Active Materials
Session Date	03/14/2012	Starting Time:	( Slot # 7 ) CO-1671

A previous paper (Pittcon 2011 # 180 - 20P  ) on fast GC focused on long (30M) capillary columns with a thick film (5u) programmed quickly over a short range from 50-75C. The analysis was much faster (>2x) as a result of the low thermal mass of the resistively heated column and resultant short cool down time. The detectors used were the photoionization detector (PID), the pulsed discharge detector (PDD) and the Far UV absorbance detector (FUV). The GC was a Model 312 portable GC.

Much of the work on “fast GC” utilizes short (5M) thin films capillary columns to elute solutes  quickly and the result is rapid but inferior separations because of the short column. New technology developed at Valco’s capillary column development center where VICI  takes  polyimide-coated fused silica (FST) and removes  the polyimide layer. Then the (FST) is electroplated with nickel.  As a result of the superior heat transfer of the electroplated nickel, we are able to  rapidly and efficiently heat and achieve excellent resolution for a 30M capillary column. 

The PLOT columns with Hayesep present some interesting opportunities for improvement with Fast GC capability. With a 30M PLOT-S, C1-C5 HC & a ramp @ 8C/min. separates the HC into 4 groups (C1-C2, C3, C4, C5) with several minute gaps between each group for this nearly 18 minute separation. A multilevel rapid ramp could easily reduce the run time to 8 minutes and the total time to 10 minutes instead of 22 minutes.

We evaluated the fast GC with a short (7.5M) column for the analysis of chemical weapons surrogates. Here we were able to reduce the analysis time from 15 minutes to 5 minutes by changing the programming from 70-130C in one minute while still resolving all the peaks.

We will also be evaluating this technology for environmental applications such as  PAH’s and PCB’s which currently can take up to an hour per sample.

Authors: Jack Driscoll, PID Analyzers, LLC and Stanley D. Stearns, VICI Valco

Selective GC Detectors and Their Role in Environmental Analysis

241st ACS National Meeting, Anaheim, CA

 

Program Area: ENVR: Division of Environmental Chemistry 

This poster will be presented twice by Jennifer Maclachlan at the Spring National Meeting:

1) Symposium Title: (ENVR018b) Sci-Mix Monday March 28, 2011 8-10pm

Celebrate IYC 2011 and be a chemistry ambassador. Join us before SCI-MIX for the Chemistry Rap Dance taping for You Tube. Click here for details.

2) Symposium Title: (ENVR006b) General Posters Wednesday March 30, 2011 6-8pm

Program Area: ENVR: Division of Environmental Chemistry-being considered for a Certificate of Merit Award

Presenting Author: Jennifer Maclachlan

Contributing Authors:

Thomas F. Daniels, CASU SCD and NCD Product Manager, Life Sciences and Chemical Analysis,  Agilent Technologies, 5301 Stevens Creek Boulevard, Santa Clara, CA, 95051-7201, United States

Stan Stearns³, President, Valco, 8399 Westview, Houston, TX, 77055, United States 

Paul Patterson⁴ , DETector Engineering & Technology, 2212 Brampton Road, Walnut Creek, CA, 94598, United States

Selective GC Detectors and their role in environmental analysis is often overlooked with the heavy reliance on mass spec detectors which is why PID Analyzers, LLC organized this group of manufacturers of GC Detectors, GC columns and users of GCs to educate this new generation of chromatographers on selective detector technologies and methods. Contributors were deliberately selected to present an overview of selective GC detectors appropriate for a wide range of environmental analysis. Description and data will include: Fixed gases and hydrocarbons with a FarUltraviolet Absorbance detector, sulfur and nitrogen detection by chemiluminescence (SCD) and (NCD), pesticide residue analysis and detection of halogenated compounds by ECD, novel application of the principles of Thermoionic Surface Ionization (TID) and FlameIonization (FID) and lastly, inert & fixed gases using micro thermal conductivity detector (TCD) and Helium Ionization Detector (HID).