Introduction HJ Method 679-2013 describes the determination of acrolein, acrylonitrile, and acetonitrile from soil and sediments by headspace-gas chromatography. It has similarities to EPA methods 8015C (nonhalongenated organics), 8030A (acrolein and acrylonitrile by gas chromatography), and 8031 (acrylonitrile by gas chromatography). Found in the soil as a byproduct of synthetic processes or from previous pesticide use, these three analytes can quickly degrade and evaporate into the air.

ExperimentalThe HJ-679 method specifies a column with an internal diameter of 530 µm, which makes it well suited for an Agilent 7890 GC equipped with an FID and Agilent 7697 headspace sample. The HJ method was followed as closely as possible. Five headspace vials were made at each calibration level by filling each vial with ~2 g of quartz sand, adding 10 mL of a matrix modifier (180 g of NaCl in 500 mL of H2O), and spiking varying amounts of a 2,000 ppm standard to achieve the required levels. Acrolein, acrylonitrile, and acetonitrile were spiked with 2 µg, 5 µg, 20 µg, 40 µg, and 80 µg.

ACROLEIN, ACRYLONITRILE, AND ACETONITRILE BY HS-GC

Demonstration of an HJ Method with an Agilent 7890 GC

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Results and DiscussionThe calibration curves determined for acrolein, acrylonitrile, and acetonitrile were found to be within method requirements (correlation coefficient of ≥0.995). The response factor was calculated over the calibration curve range, and an RSD was determined for each analyte. Acrolein was found to have the highest response factor RSD, at 10 %, likely due to its high volatility. Both acrylonitrile and acetonitrile yielded response factor RSDs of 5.3 %.

Instrument conditionsParameter Value

Agilent 7890 GCInlet 150 °C, Split 5:1

Column Agilent J&W DB-WAX UI, 30 m × 0.53 mm, 1.00 µm, 125-7032UI

Column flow 4.5 mL/min

Oven 40 °C (5 minutes) then 5 °C/min to 60 °C then 30 °C/min to 150 °C (5 minutes)

FID 250 °C

Agilent 7697 Headspace SamplerOven 75 °C

Loop 105 °C

Transfer line 150 °C

Vial equilibration 30 minutes

Injection duration 0.1 minutes

Vial 20 mL

Shaking On, level 1

Vial fill flow 50 mL/min

Vial fill pressure 8 psi

Vial pressure equilibration time 2 minutes

Loop fill ramp rate 20 psi/min

Final loop pressure 1.2 psi

Loop equilibration 0.2 minutes

0 4 8 12 16 20 24 28 32 36 40 44 48 52 56 60 64 68 72 76 80 840

0.10.20.30.40.50.60.70.80.91.0 Acrolein

y = 12005.609609*x + 5790.506646R2 = 9967

×106

Resp

onse

Concentration (ng/mL)

Figure 1. The calibration curve for acrolein from 2 µg to 80 µg gave a correlation coefficient of 0.997.

×106

Acrylonitrile

Concentration (µg/L)-4 0 4 8 12 16 20 24 28 32 36 40 44 48 52 56 60 64 68 72 76 80 84

Resp

onse

00.40.81.21.62.02.42.83.2

y = 39797.225910*x – 10068.903978R2 = 0.9983

Figure 2. Calibration curve for acrylonitrile gave a correlation coefficient of 0.998 for five levels, ranging from 2 µg to 80 µg.

×105

Acetonitrile

Concentration (ng/mL)

Resp

onse

012345 y = 6896.947165*x – 1637.622097

R2 = 0.9978

-4 0 4 8 12 16 20 24 28 32 36 40 44 48 52 56 60 64 68 72 76 80 84

Figure 3. Acetonitrile gave a correlation coefficient of 0.998 for five calibration levels, ranging from 2 µg to 80 µg.

1 2 3 4 5 6 7 8 9 10120,000121,000122,000123,000124,000125,000126,000127,000128,000129,000130,000131,000132,000133,000134,000135,000136,000

Time (min)

Resp

onse

1

2

3

Figure 4. Acrolein (1), acrylonitrile (2), and acetonitrile (3) at 1 mg/kg eluted in under 10 minutes.

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© Agilent Technologies, Inc. 2017 Published in USA, November 1, 2017

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ConclusionThe Agilent 7890 GC configured with an Agilent 7697 headspace sampler achieves the performance specifications of HJ679-2013. Correlation coefficients were found to be 0.995 or better, while response factor RSDs are not specified in the method. Acrolein, acrylonitrile, and acetonitrile yielded RSDs of 10 % or better for five replicate vials. The 10-minute run time is typical of HJ679-2013, but could be shortened easily by implementing a smaller id column.