CONTINUOUS MONITORING OF BTEX AND PAHs USING AUTOMATIC THERMAL DESORPTION-GAS CHROMATOGRAPHY
Franck
1.
2.
3.
4.
1
Amiet ,
Fayez
2
Al-Senan ,
Jean-Philippe
3
Amiet ,
Michel
4
Robert
and Damien
4
Bazin
Chief Executive Officer, Chromatotec, Saint-Antoine, France+
Chief Executive Officer, Al-Sinan & Partner Trading Co., Jubail , Saudi Arabia*
Export Project Manager, Chromatotec, Saint-Antoine, France +
Research & Development Department, Chromatotec, Saint-Antoine, France +
Address:
+ 15 Rue d’Artiguelongue 33240 SAINT-ANTOINE – France Tel : +33 557 940 626 -- Contact: [email protected]
* KYTOS ARABIA, PO Box 374 Jubail 31951 Saudi Arabia Phone : +966 13 362 3939 x 13 Email: [email protected]
Naphthalene in air
Naphthalene in water
Analyzer configuration: airmoVOC C6-C12
Analyzer configuration: airmoVOC C6-C12
Permeation tubes
Liquid standard
- 20 ng/min
- 60 °C
502.2 CAL2000 MegaMix Mixture (Restek)
2000 µg/L
-Analytical conditions
- Sampling times
- 300 s – 1200 s
- At 3 ppb (naphthalene)
Analytical conditions
-Mass
2,5 – 500 µl in 5 L of water
- 10 to 50 ng
(A)
(B)
25000
20000
15000
10000
5000
35000
25 ppb(m)
30000
25000
20000
15000
10000
5000
0
0
0
2
4
6
8
10
12
y = 1,791020x
R² = 0,984007
NAPHTALENE
Concentration (µg/L)
Naphthalene area (a.u.)
30000
Naphthalene area (a.u.)
Polycyclic Aromatic Hydrocarbons (PAHs) are a group of over 100 different chemicals that are known to be formed
typically during incomplete combustion of organic matter at high temperature. Due to their carcinogenic/mutagenic
effects, 16 PAHs are currently listed as priority air pollutants. Actual analytical methods dedicated to monitor PAHs
require multistep sampling preparations and are not suited for continuous monitoring. Automatic Thermal
Desorption-Gas Chromatography equipped with Flame Ionization Detector (AUTO-TD-GC-FID) is the standard
method for the monitoring of volatile and semi-volatile hydrocarbons. This technique allows for identifying and
quantifying continuously hydrocarbons from ethane to naphthalene, including the BTEX. The main goal of this work
was to implement a new and simple method for sampling and determination of BTEX and PAHs in gas and solid
phase in ambient air by using thermal desorption technique followed by gas chromatography equipped with two
detectors: a FID and a Mass spectrometer. A detailed study was carried out to optimize the experimental method in
each of its phases, including sampling, thermal desorption, analytical separation, and detection. First, the limits of
use were determined during the laboratory phase using certified cylinders for VOCs (BTEX and PAMS 58) and liquid
standards for the 16 PAHs. Then the applicability of the novel methodology was tested in real environment, namely,
at 200 meters from a highway analyzing BTEX and PAHs.
14
0
Mass of Naphthalene injected (ng)
10
20
30
40
50
60
20 ppb(m)
15 ppb(m)
10 ppb(m)
5 ppb(m)
0 ppb(m)
Mass of Naphthalene injected (ng)
0
2
4
6
Area
Calibration curve for Naphthalene changing the sampling time (A)
and Naphthalene concentrations (B)
Chromatogram obtained with FID
detector
8
10
12
NAPHTALENE
Calibration curve for Naphthalene
BTEX analysis
Analyzer configuration: airmoVOC C6-C12
Test carried out using NPL certified cylinders: Concentrations from 0.5 up to 45 µg/m3
Naphthalene trends
near Bordeaux
Analyzer configuration: airmoVOC C6-C12
Naphthalene concentration (ng/m3)
600
Calibration curves for Benzene, Toluene, Ethylbenzne,
M&P-xylenes and O-xylenes1
PAMS 58 analysis
Analyzer configuration: airmoVOC C6-C12
Test carried out using PAMS 58 certified cylinders: Concentrations from 0.5 up to 45 µg/m3
400
300
Analyzer configuration: airmo C10-C20+
Sample
SV Calibration Mix #5/610 PAH
Mix (Restek)
16 components
2 mg/ml in dichloromethane
200
100
0
01/01/15 06/01/15 11/01/15 16/01/15 21/01/15 26/01/15 31/01/15 05/02/15
Chromatogram obtained with FID
detector
171 ng/m3 in January 2015
Naphthalene concentration (ng/m3)
Chromatogram obtained with FID
detector for BTEX sample1
500
PAHs analysis
600
500
400
300
200
100
0
25/6/15 30/6/15 5/7/15 10/7/15 15/7/15 20/7/15 25/7/15 30/7/15 4/8/15
Chromatogram obtained with MS
Time
70 ng/m3 in July 2015
Chromatogram obtained with FID
Calibration curves for PAMS 58 compounds
detector
for PAMS 58
1 BTEX
tests carried out at the NPL of London in collaboration with Dr. N. Martin.
Concentration trends of ambient air
The results show that the airmoVOC C6-C12 is suited for the measurement of BTEX, PAMS 58 compounds and
Naphthalene in air and in water. The measured concentrations of Naphthalene in ambient air were 171 and 70 ng/m3
in January and July respectively. The airmo C10-C20+ is capable of measuring the first PAHs. Further studies will
characterize the capability of the system for the measurement of PAHs in the gas and particle phase.
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