This document discusses using a hand-held mid-infrared spectrometer to rapidly predict total petroleum hydrocarbons (TPH) in soil. TPH is a complex mixture derived from crude oil that is a major soil pollutant. Traditional analysis is time-consuming and expensive. The authors propose using diffuse reflectance mid-infrared spectroscopy with partial least squares regression as a faster, cheaper alternative. They describe developing a model using 199 contaminated soils and validating it in the field at contamination sites, where it rapidly guided remediation work. The technique is now commercially available as RemScan and continues to be improved to analyze more soil types and contaminants.

1. The use of a hand-held mid-infrared spectrometer for the
rapid prediction of total petroleum hydrocarbons in soil
Water for a Healthy Country Flagship
Les J. Janik, José M. Soriano-Disla, Sean T. Forrester, Michael J. McLaughlin,
Grant Webster, Richard Stewart
05 December 2013 Infrared workshop, FAO Headquarters (Rome)

2. The use of a hand-held mid-infrared spectrometer for the rapid prediction of total petroleum hydrocarbons in soil | Janik et al.
1. Background
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3. Complex mixture of aliphatic hydrocarbon chains (C10-
C36) derived from crude oil
Major environmental pollutant: spills from production,
storage and distribution
Impacts: soil, sediment, water, biology and humans
Risk assessment and remediation needs to be quick and
is expensive
The use of a hand-held mid-infrared spectrometer for the rapid prediction of total petroleum hydrocarbons in soil | Janik et al.
TPH Background
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4. Traditional approaches
Laboratory: Supercritical fluid extraction followed by silica clean-up
and gas-chromatography with flame ionization detector (GC-FID)
Field: IR method (ATR) which requires extraction prior measurement
We need a reliable, quick, cheap and “in situ” technique
The use of a hand-held mid-infrared spectrometer for the rapid prediction of total petroleum hydrocarbons in soil | Janik et al.
TPH traditional analysis
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5. We propose diffuse reflectance mid-infrared spectroscopy together with
partial least squares as an alternative for the “in situ” prediction of TPH (C10-
C36)
Advantages
Rapid
No sample pretreatment
In situ
Multiple analytes prediction
The use of a hand-held mid-infrared spectrometer for the rapid prediction of total petroleum hydrocarbons in soil | Janik et al.
DRIFT-PLSR as an alternative
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6. The use of a hand-held mid-infrared spectrometer for the rapid prediction of total petroleum hydrocarbons in soil | Janik et al.
Our hand-held spectrometer
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Full FT-IR Hand-held (Agilent)
6000-650 cm-1
15 s scan and 8 cm-1 resolution
~3 kg
Blue-tooth PDA with PLS software
Battery

7. Mid-infrared sensitive to C-H bonds
The use of a hand-held mid-infrared spectrometer for the rapid prediction of total petroleum hydrocarbons in soil | Janik et al.
TPH peaks
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NIR MIR
NIR (5000-4000 cm-1) and MIR (4000-1200 cm-1) spectra of
liquid diesel, crude oil and n-hexane
Forrester et al. 2013 (SSSAJ 77, 450-460)
~2730 cm-1 (-CH3)
-CH3
0
0.1
0.2
0.3
0.4
260028003000
Absorbance
Wavenumbers
Diesel
SOM
Diesel in clay,
and soil organic
matter spectra
-CH2
~2950 cm-1 (-CH3) -CH2

8. The use of a hand-held mid-infrared spectrometer for the rapid prediction of total petroleum hydrocarbons in soil | Janik et al.
The PLSR model
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4540-4120 3000-2600
PCs R2 RMSE RPD PCs R2 RMSE RPD
9 0.84 853 2.4 7 0.92 601 3.4
Selection of optimal spectral range and PLSR development in Forrester et al.
2013 (SSSAJ 77, 450-460)
n = 199 TPH contaminated soils from Australia (0-15,000 mg/kg)
Air-dried
Partial least squares and trained by cross-validation
(2960, 2930, 2850, 2730)(4330, 4260)

9. The use of a hand-held mid-infrared spectrometer for the rapid prediction of total petroleum hydrocarbons in soil | Janik et al.
Commercialisation of the technique
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2008-2009: collaboration project with Ziltek Pty Ltd (South
Australia)
2012: Method patented in Australia
2013: method patented in USA
2013: Ziltek Pty Ltd. releases the technology as REMSCAN
2013: Publication in SSSAJ describing the patented method
(Forrester et al., 2013)

10. The use of a hand-held mid-infrared spectrometer for the rapid prediction of total petroleum hydrocarbons in soil | Janik et al.
Challenges
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Presence of moisture: leave the
sample drying, software cut-off
Soil heterogeneity: repeated scans,
mixing the sample
Sample entering into the cone
nose: instrument squared to the
surface and sample tamped flat
10002000300040005000
Wavenumber (cm-1)
Absorbance
TPH
Moist sample

11. The use of a hand-held mid-infrared spectrometer for the rapid prediction of total petroleum hydrocarbons in soil | Janik et al.
Challenges
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Soil type (TPH spread in sandy soils vs “shielding” effect in clay soils): site
specific or local models. Local models:
Spectral library divided in clusters linked to textural classes
Unknown spectra allocated to the correspondent model
Within each model, 5 TPH range concentrations models: final model
dependent on the TPH value predicted

12. The use of a hand-held mid-infrared spectrometer for the rapid prediction of total petroleum hydrocarbons in soil | Janik et al.
2. Examples of field uses
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13. Diesel leaked from a storage
facility and captured in an
emergency bund area
Site specific calibration to quantify
diesel in the bund area and
monitor remediation works
Remediation work completed in 4
days (200 samples/day)
19 ´blind´ samples sent for
analysis
The use of a hand-held mid-infrared spectrometer for the rapid prediction of total petroleum hydrocarbons in soil | Janik et al.
Case study 1: Western Australia
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R2 = 0.997

14. Ageing power transformer removed. Oil contamination in the footings
RemScan “guided” the remediation work: pit declared “clean” < 1000 mg/kg
The use of a hand-held mid-infrared spectrometer for the rapid prediction of total petroleum hydrocarbons in soil | Janik et al.
Case study 2: South Australia
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Samples from from walls and floor sent to reference laboratory
Reference analysis confirmed TPH predictions
R2 = 0.994

15. The use of a hand-held mid-infrared spectrometer for the rapid prediction of total petroleum hydrocarbons in soil | Janik et al.
Case study 3: South Australia
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16. The use of a hand-held mid-infrared spectrometer for the rapid prediction of total petroleum hydrocarbons in soil | Janik et al.
Final remarks
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DRIFT-PLSR using a hand-held spectrometer is suitable technique for the
rapid, cheap and accurate prediction of TPH
RemScan commercialy used
On-going work
Inclusion of new soils in the global calibrations
Inclusion of additional contaminants

17. • Government of Valencia (Conselleria de Educación) for a Post-
Doctoral Fellowship
• University of Adelaide
• Ziltek Pty Ltd.
The use of a hand-held mid-infrared spectrometer for the rapid prediction of total petroleum hydrocarbons in soil | Janik et al.
Acknowledgements
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18. Thank you
Sustainable Agriculture Flagship
CSIRO Land and Water (Sustainable Agriculture Flagship)
Jose Martin Soriano Disla (PhD)
t +61883038425
e jose.sorianodisla@csiro.au
w www.clw.csiro.au