ISCC 2014

Poster # N.06 Expanding analytical capabilities for laboratory GC

through the use of an external isothermal zoneJuan

Aybar1, James McCurry2, Bernhard Rothweiler3

1 Agilent Technologies, Carretera Nacional VI, Km 18.2, 28232 Las Rozas, Spain 2 Gas Phase Division – Agilent Technologies, 2850 Centerville Road, 19808 Wilmington, United States

3 Agilent Technologies Sales & Services GmbH & Co. KG - Hewlett-Packard-Str. 8, Waldbronn, 76337, GERMANY

Introduction

Complex GC applications can require using multiple valves for column switching, heart cutting, and multi-dimensional analysis. Similarly, columns used for certain application

have temperature limitation for packing materials or stationary phase films. The addition of a large valve oven to the 7890B GC provides an external isothermal zone

addresses these requirements. Capable of supporting a combination of up to six (6) column mandrels of valves the large valve oven provide thermal regulation up to 300 °C.

When applied to Refinery Gas Analysis (RGA) the new system provides stable response for oxygen (O2) and hydrogen disulfide (H2S) with profiling of hydrogen,

hydrocarbons (C6+ as backflush), and permanent gases in eight (8) minutes using micropacked columns, and seventeen (17) minutes using standard packed columns. The

additional capacity for multiple valves and columns in a single heated zone also allows for the analysis of reformulated fuels per ASTM D3606, D4815 and D5580.

Experimental

Table 2. Select method

conditions for LVO Reformulated

Fuels Analyzers

Instrument Agilent 7890B GC for RGA

Splt/Splitless Inlet 120℃, 100:1 Split

FID (front) 250℃

TCD (rear) 260℃, He carrier,

Ref. 30 mL/min, Makeup 2 mL/min

TCD (side) 250 ºC, N2 carrier

Ref. 45 mL/min, Makeup 2 ml/min

Negative Polarity

Main Oven Program 60 ºC ( 1 min) to 80 ºC @ 20 ºC/min

to 190 ºC @ 30 ºC/min

LVO Program Isothermal, 65 ºC and 70 ºC

Method performance

Results and Discussion

Refinery Gas Analysis Maintenance of isothermal temperature in the LVO allow for simultaneous

reproducible determination of H2S and O2. Run time for the Fast and Standard

RGA configurations is 8 and 16 minutes respectively. Figure 5 depicts

chromatography and reproducibility data for the LVO RGA with Standard 1/8”

columns. Table 3 summarizes reproducibility data for the LVO RGA with Standard

1/8” columns.

Large Valve Oven

The new Large Valve Oven for the 7890B GC expands the analytical capacity and

provides flexibility for GC methods that require complex valve and multiple column

configurations. The isothermal zone provides reproducible analysis of RGA

components and simultaneous detection of H2S and O2. The LVO allows multiple

ASTM gasoline methods to be configured on a single GC. Run sequentially , the

methods meet or exceed ASTM performance requirements. Higher main oven

temperature (135 °C) has no effect on the lower LVO temperature (60 °C).

Conclusion

Large Valve Oven Refinery Gas Analysis

This work developed application for Refinery Gas (RGA) analysis using

Micropacked columns and standard packed columns. Table 1 outlines select

analytical conditions for the RGA systems.

Similarities Between Each Reformulated Fuel Methods

All method have the same GC hardware requirements, e.g., Inlets, detectors,

plumbing and valve configuration same separation scheme:

• 2-D separation using polar TCEP micro-packed primary column

• 20% TCEP on 80/100 Chromosorb PAW, 22“ x 1/16“ stainless

• Only one difference in instrument requirements – non-polar capillary column

• D4815 – 2.65 mm methyl silicone, 30m x 0.53mm

• D5580 – 5 mm methyl silicone, 30m x 0.53mm

Large Valve Oven (LVO)

The LVO expands the analytical capabilities of the standard GC oven and

provides easy access for system maintenance. Using a single heated zone, this

accessory provides an isothermal zone to house six (6) heated internal positions

for valves or column mandrels, and four (4) needle valve positions. Figure 1

below shows the front and back of the LVO. Figures 2, 3 and 4 represent the

configurations for the Fast RGA, Standard RGA and Reformulated Fuels

analyzers respectively.

Fig 5. S/N for Dibenzo(a,l)pyrene (500 pg), CCM vs standard operation

Reformulated Fuel Analysis All three methods, D5580, D4815, and D3606 meet or exceed ASTM methods

performance criteria. Figure 6 below summarizes reproducibility data for all three

methods.

Fig 6. Performance Data for ASTM Methods

D5580 (top), D4815 (middle)and D3606 (bottom

right and left)

Large Valve Oven Reformulated Fuel Analysis

Leveraging the flexibility offered by the LVO, three (3) Reformulated Fuel

Analysis applications, ASTM D4815, D5580 and D3606., were configured on a

single GC. Table 2 reflects analytical conditions for each method.

Parameter D3606 Method`

carrier gas helium

Inlet Purge Packed @ 59.4 psi

Inlet temperature 200 Deg C

Inlet total flow 23 mL/min

Septum purge flow 3 mL/min

Column flow 20 mL/min

Aux pressure 35.5 psi

TCD temperature 250 deg C

LVO Temperature 60 deg C

Main oven temperature 135 deg C isothermal

Backflush time 2.5 min

Parameter D4815 Method D5580 Method

carrier gas helium or N2 helium or N2

Inlet Split/Splitless Split/Splitless inlet temperature 200 Deg C 200 Deg C

inlet pressure 9 psi (constant P) 25 psi (constant P) TCEP column flow 5 mL/min 10 mL/min

split vent flow 70 mL/min 100 mL/min

split ratio 15:1 100:1

PCM pressure program

13 psi for 14 min>99 psi/min to 40 psi

23 psi for 12.1 min>99 psi/min to 40 psi

HP-1 column flow 3 mL/min 10 mL/min

FID temperature 250 deg C 250 deg C

LVO temperature 60 deg C 60 deg C

Main oven temperature 60 deg C isothermal 60 C for 6 min>2 C/min to 115 C>115 C for 1.5 min

Table 1. Select method conditions for LVO Refinery Gas Analyzers

Figure 1. Base LVO configuration

Micropacked LVO Plumbing

Figure 2. LVO for Fast RGA,

micropacked columns Figure 3. LVO for Standard RGA, 1/8”

columns

Figure 4. LVO for Reformulated Fuels

Analysis (D4815, D5580, D3606

Compound Concentration RT 65 C RT 70 C Area 65 C Area 70 C

C6+ 0.06 0.026 0.022 0.35 0.31

Methane (FID) 4.99 0.009 0.011 0.19 0.12

Ethane (FID) 4 0.02 0.016 0.21 0.15

n-butane 0.3 0.103 0.038 0.23 0.16

t-2-butane 0.3 0.13 0.055 0.22 0.19

1-butene 0.3 0.13 0.056 0.34 0.26

n-pentane 0.1 0.082 0.034 0.29 0.22

Hydrogen 12.1 0.021 0.037 0.13 0.1

Oxygen 2.98 0.015 0.01 1.36 0.7

Nitrogen balance 0.026 0.017 0.18 0.12

Carbon Monoxide 1.52 0.044 0.023 0.16 0.12

Carbon Dioxide 2.01 0.11 0.048 0.13 0.14

Methane (TCD) 4.99 0.031 0.02 0.25 0.13

Ethane (TCD) 4 0.099 0.055 0.22 0.14

Table 3. Repeatability for Select Refinery Gas Components (% RSD for retention times and areas large valve oven temp 65 and 70 °C)