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IS 5182-11 (2006): Methods for measurement of air
pollution, Part 11: Benzene, Toluene and xylene (BTX) [CHD
32: Environmental Protection and Waste Management]
“!ान $ एक न’ भारत का +नम-ण”
Satyanarayan Gangaram Pitroda
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“!ान एक ऐसा खजाना > जो कभी च0राया नहB जा सकता हहहहै””ै”
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IS5182 (Part11):2006
Indian Standard
METHODS FOR MEASUREMENT OF
AIR POLLUTION
PART 11 BENZENE, TOLUENE AND XYLENE (BTX)
(Second Revision )
,
ICS 13.040.30; 71.080.15
0 BIS 2006
BUREAU OF INDIAN STANDARDS
MANAK BHAVAN, 9 BAHADUR SHAH ZAFAR MARG
NEW DEL HI 110002
September 2006 Price Group 8
Environment Protection and Waste Management Sectional Committee, CHD 32
FOREWORD
This Indian Standard (Part 11) (Second Revision) was adopted by the Bureau of tndian Standards, after the drafl
finalized by the Environment Protection and Waste Management Sectional Committee had been approved by the
Chemical Division Council.
The aromatic hydrocarbons, namely, benzene, toluene and xylene have many industrial uses, most notably as asolvent
for numerous materials and as a firel additive. They are also used in the manufacture of various chemicals, rubber,
insecticides. pharmaceuticals, explosives, etc. Though they are very usefil chemicals, they are also extremely hazardous.
They are highly flammable. While benzene iswell known to becarcinogenic, there isrecent evidence of carcinogenicity
of toluene and xylene at high concentrations in experimental animals. It should also be noted that any future
epidemiological observations of cancer risks associated with toluene or xylene would have to take account of the
suspected effects of benzene impurities. Regular and systematic procedures for inspection are, therefore, necessaty to
ensure safety against the hazards involved.
This standard was first published in 1982 and revised itin 1993 based on the development of the analytical procedures
to introduce a newer method having a different type of collection, resorption media and use of N,
N-Bis-cyanoethylformam ide (BCEF) for determination ofbenzene only, The Committee responsible for the formulation
ofthis standard fiu-therdecided to revise itbased onthe experience gained during the last decade aswell astechnological
development in the field. During the revision method for determination of toluene and xylene are incorporated. The
revised methods include both active and passive sampling using low flow pump. Apart from the conventional CS2
resorption, the modem-techniques of automated thermal resorption without use oforganic solvents isalso incorporated
inthis revision.
‘[’hereisno 1S() Standard on the subject. The standard isprepared based on the measuring techniques available and use
in India,
The Committee composition responsible for the formulation of this standard isgiven atAnnex A.
In reporting the results of a test or a nalysis made in accordance with this standard, if the final value, observed
or calculated, is to be rounded off, it shall be done in accordance with IS 2 : 1960 ‘Rules for Founding off numerical
values (revise@’.
IS 5182 (Part 11):2006
Indian Standard
METHODS FOR MEASUREMENT OF
AIR POLLUTION
PART 11 BENZENE, TOLUENE AND XYLENE (BTX)
(Second Revision)
1 SCOPE pump with a low flow controller with operating range
between 5 to 500 mlhnin (+0.2 ml/min) to suck the air
This standard (Part 11) prescribes active and passive
sample.
sampling techniques with three gas chromatography based
analytical methods for measurement of benzene, toluene
NOTE — Wherever necessary intrinsically safe pumps may be
and xylene in air.
used.
2 REFERENCES
4.2.2 Sampling Sorbent (Sample) Tubes — Glass lined
The following standard contains provisions, which (or fused silica lined) stainless steel tube or stainless steel
through reference inthis text constitute provisions of this sorbent tubes of 6 mm O.D., 8.9 cm long tubes with a
standard. At the time of publication, the edition indicated 6 cm of sorbent bed of 200 mg of activated charcoal
was valid. All standards are subject to revision and parties (coconut shell) or other suitable adsorbent, A typical
to agreements based on this standard are encouraged to sorbent/sampie tube is shown in Fig. I and Fig. 2.
investigate the possibility of applying the most recent
edition of the standard indicated below: Modular glass or stainless tube (C)D 6-8 mm length
10-15 cm) packed with chromatography grade coconut
ISNo, Title shelI activated charcoal, chromatography grade. Tube
4167:1980 Glossary of terms relating to air must have provision for fitting of backup section with
pollution (first revision) provision to measure pressure drop across the tube during
sampling. The minimum quantity of charcoal required in
3 TERMINOLOGY front section is200 mg and inbackup section 50mg. Glass
beads or any other porous inert material must be packed
For the purpose of this standard, definitions given in
in inlet part of tlont section for uniform distribution of
IS4167 shall apply.
sucked air through tube at the time of sampling.
4 METHOD 1 (ACTIVE SAM P.LING USING
4.2.3 Gas Chromatography — Any suitable gas
ACTIVATED CHARCOALTUBES, DESORBED BY
CARBON DISULPHIDE) chromatography with flame ionization detector (FID)with
fissed silica capillary columns having a length of 25 m or
4.1 Principle more, an internal diameter of 320 ~m or below and with a
stationary phase film thickness less than 1.5 pm as follows
The charcoal tubes are available in different sizes and
or equivalent may be recommended:
contain varying amount ofactivated charcoal. The ambient
air is sucked through the tube using a low flow sampler
Capillary 624 Column : Coating: cyanopropyl phenyl
used for COIIection of BTX sample inawdy that results in
poIysiloxane, Length x ID :
an enrichment of the relevant substances in the activated
30 m x 0.25 mm, Film thickness
charcoal. Resorption ofthe adsorbed benzene isdone using
(d,) : I.4 pm ,
carbon disulphide (CS2). The substances desorbed inthe
CS2areanalyzed by capillary gaschromatography. Aflame Capillary Column :Coating :5 percent phenyl, 95
ionization detector (FID) is used for analysis while percent dimethyl polysi Ioxane
quantification is performed using the internal/external Length x ID :25 m x 0.20 mm,
standard. Film thickness (d) = 0.33 ~m
4.2 Apparatus Wall Coated Column :Coating: Fused Silica PQNA
CB, Length x ID :50 m x 0.21
4.2.1 Low Volume Pump — Portable, battery powered mm, Film thickness (c+): 0.5 pm
1
-1S5182 (Part 11):2006
SEALINGCAP
HIGH-PURITY
GLASSWOOL
GLASS“TUBE
PRECISION
BACKUPSORt3ENTLAYER LC)CKSPFUNG
SORBENTLAYER
FOAMSEPARATOR
PRECISIONSEALEDTIP
FIG. 1 SORBENT/SWPLETUBEFORACTIVESAMPLINGFILLEDWITH
ACWAIHI COCONUTSHELLCHARCOAL(CSC)
Capillary Column :Coating : Fused silica 100 4.4.2 Sample Tubes Labelling
percent dimethyl polysiloxane,
Sample tubes are Iabelled with a unique identification
Length x lD:30m x 0.32 ID, number and the direction ofsampling flow. Ifempty sample
Film thickness (dJ: l.O~m
tubes are obrained without labels, it is important to label
4.3 Reagents and condition them before and after they are packed with
adsorbent prior to use them for sampling.
4.3.1 Suitable Adsorbent — Chromatogmph ic grade
activated charcoal (coconut shell) or other suitable
adsorbent, that is, Chromosorb 106 or other suitable
.adsorb.ent having particle size inthe range 60 to 80 mesh.
4.3.2 Carbon Disulphide (CSZ) — Chromatographic
grade, Purity >99.9 percent (GLC), Residue <0.0005
percent, Benzene 0;001 percent, HZO<0.02 percent.
FRONTSECTION
4.3.3 Benzene — Chromatographic grade, Purity> 99.9
percent (GLC), Residue <0.0003 percent, HZO<0.02
percent.
4.3.4 To[uene — Chromatographic grade, Purity >99.9
percent (GLC), Residue <0.0003 percent, H,O <0.02
percent.
4.3.5 Xylene — Chromatographic grade, Purity >99.9
percent (GLC), Residue <0.0003 percent, H,O <0.02
percent.
4.3.6 Carrier Gas — Helium or Nitrogen of purity
>99.9 percent, HZO<0.02 percent, Residues <0.0003 BACKSFCTION
percent.
4.4 Sampling
4.4:1 Selection ofSorbent Tube — Samples are collected
in glass sampling tube filled with a activated charcoal
(coconut shell), Chromosorb 106 or other suitable
adsorbent. FIG.2 IwsT ANDOUTLETOFTHESORBENT/SAMPLETUBE
2
IS 5182 (Part 11):2006
4.4.3 Sampling Procedure and Sampling Rate charcoal or activated charcoal/silica gel for storage and
transportation of multiple tubes. Store the multi-tube
A sample is collected by opening a tube at two ends,
storage container in a clean environment at 4* 1“C.
connecting it to a sample pump, and pulling air through
, the tube with the pump. Airborne chemicals are trapped
4.5 Procedure
onto the surface of the sorbent:
a) Two tubes are used in series to take care of ~ ~ ~ ~ajibration
breakthrough (if any) compatible to the thermal “ “
7-R=’ ‘4SAM’LE’NL
L
SAMPLINGTUBES
DIGITAL
LCD
‘
no
[
00
00
t--
0 ~ BUILTIN I
ROTAMETER
LOWFLOWPUMP
FIG.3 Low FLOWSAMPLINGPIJMPWITHSAMPLINGTRAIN
desorber. The sampling is carried out using low Prepare a mix stock standard solution of 50 pg/pl of
flow sampler. The schematic diagram of sampling benzene, toluene and xylene each gravimetrically using
train is given in Fig. 3. amicro syringe.in the eluting solvent that isCS2.Prepare
fi-u-therdiluted solutions of concentration range of 10, 1.0,
b) Keep the tube inavertical position during sampling
0.10 ~g/@ with CS2from stock standard in a clean vial,
to prevent the possibility of channeling that can
Make up to 1 ml solution. Introduce immediately 1 @
lead to tinder sampling,
standard solution into the injector of GC directly and plot
c) The arrow on the tube indicat e s air flow direction the curve between the concentration and response (peak
and should point to the tube ho l der and pump. If area). Prepare fresh standard solutions with each batch of
no arrow ispresent, the smallest section should be samples. Atypical chromatogram of standard mixture is
near the tube holder.
given in Fig. 4.
d) Sampling flow rate inthe range of 20-100 ml/min
is required (+2 percent) for ambient air. 4.5.2 Analytical Procedure
e) A sample component may breakthrough from the Samples collected through active sampling (sorbent
back end of tube, if excessive flow rates are used. tubes) are extracted or desorbed by conventional
Sample is to be discarded, if the breakthrough is solvent (generally 1-5 ml of carbon disulphide) using
observed more than 10 percent. If analyzed ultrasonication for 15 min to remove analyte from the
concentration in backup section is more than sorbent material. Desorbed samples are analyzed using
iOpercent of front section, sample needs to be gas chromatography (GC) fitted with capillary column and
discarded. flame ionization detector (FID). A single tube may
provide enough samples to permit several analyses.
The-tube is then sealed with push-on caps, and sent to a
laboratory for analysis. The following set of conditions isgenerally used:
a) Gasf70w:
4.4.4 Storage of Blank and Sampled Tubes
Nitrogen :30 ml/min (FID make up + Column),
Seal clean, blank sorbent tubes and sampled tubes using
(Column flow 1ml/min approximately)
inert fittings and PTFE ferrules. Wrap capped tubes
Hydrogen :30 ml/min
individually inuncoated aluminum foil. Use clean, sealable
metal cans containing a small packet of activated Air :300 ml/min
3
1SS182 (Part 11):2006
‘w
8
Co m
I I I
>
I
I
) )
1-
FIG.4 TYPICAL CALIBRATIONCHROMATOGRAMOFBENZENE,TOLUENEANDXYLENE
(Using column PE 624 at 0.0174 ~g/pl concentration of analytes)
NOTE — Instead ofnitmgen, helium may alsobeusedascarrier 4.6 Calculation
gasfor tlow setting andcorresponding retention time ofanalytes
Amount of analyte compound found on tube can be
may vary.
converted into mg/m3, by using the focmula:
Capillary column 624, Coating: cyanopropyl phenyl
polysiloxane, Length x ID : 30 m x 0.25 mm, Film Volume of air (m3)(sucked through Sxt
.—
thickness (d) :1.4 pm the adsorption tube) 106
where
b] Temperature programming
S = samplingrate, in ml/min; and
Injection port :250”C
t = sampling time, in min.
FID :300°c
Concentration (pg/m3)
Column/Oven : 50”C (hold for 3 rein) ,rampl @)10°C/ CXV, X103
(at ambient condition) =
min to 1400C (1rein) ramp 2@ 20°C/min to 24o (1 rein) V2x v,
where
Injectionvohtme: 5.111,Total run time: 19.5 rein, Split: 10
C = amount of compound found injection sample
vohtme from standard curve, in pg/I.Ll;
. Benzene RT 6.80 rein, -Search window : 1.00 s,
V,= total volume of the sample extracted in ml;
3.00 percent
Vz= volume of sample extract injected into GC, in
e Toluene R.T 9.18 rein, Search window: 1.00 s,
pl; and
3.00 percent
Vq= volume of air sucked through thehtbe, inm’.
. Xylene RT 11.37 rein, Search window: 1.00 s,
3.00 percent
Blank value is to be subtracted from the amount of
compound found in the sample.
NOTE — Temperature programming and retention time (RT) of
analyte may vary column tocolumn togetappropriate resolution
Concentration (pg/m3)
aocfcoanrdailnygtetopneaatkusr.eaInnjedcptiroonbabvleolucmonecenatnradteisopnlitofmanaay[yatelsoprevsaernyt at (STP) —— CX 101.3 (273+T)
273 XP
intheextract.
4
IS5182 (Part 11):2006
where 5.2.2 Sampling Sorbent (Sample) Tube — Automated
Thermal Resorption (ATD) tubes of stainless steel filled
C= concentration at ambient condition, in pg/m3;
with absorbing material are required. Stainless steel or
T = temperature of the ambient air, in ‘C; and
glass sorbent tubes (see Fig. 5)of 8.9 cm long, 6mm O.D.
P = atmospheric pressure, in kPa. with a 6 cm sorbent bed in the central portion packed
with greater than 200 mg of solid adsorbent material
5 METHOD 2 (ACTIVE SAMPLING USIN-G (that is Tenax TA, Chromosorb 106 or any other suitable
TENAX/CHROMOSORB 106 SORPTI-ON adsorbent).
TU-BES,DESORBED THERMALLY)
NOTE — Tobesuitable forthermal resorption, sorbentmustmeet
5.1 Principle exact specifications that include low contaminant background,
high thermal stability and sufficient adsorptive strengthtoretain
Thermal resorption tubes filled with Tenax TA or other components ofinterestandshouldalsoreleasethemquickly when
suitable adsorbent as Chromosorb- 106, etc, are used for heat isapplied.
adsorption of benzene, toluene, and xylene in place of
charcoal tube. The ambient air is sucked through the tube 5.2.3 Automated Thermal Resorption Apparatus
using alow flow personal sampler in away that results in (Two-Stage Thermal Resorption)
anenrichment ofthe relevant substances on the adsorbent. Two-stage automated thermal resorption isrecommended
These tubes are directly connected to the automated to use heat and a flow of inert (carrier) gas to extract
thermal desorbers coupled with the gas chromatography volatiles from a solid adsorbent matrix directly into the
equipped with capillary column and flame ionization carrier gas and transfer them to downstream system
detector. The thermal resorption technique offer the elements such as the analytical column of a GC.
advantage of agreatly improved analytical sensitivity, as
solvent isnot used inthis process and the collected sample Two-stage automated thermal resorption is used for the
isnot diluted. Inmost cases analytical recovery isclose to best high resolution capillary chromatography (that is,
100 percent and resorption efficiency corrections are not analytes desorbed from the sorbent tubs must be refocused
required. before being rapidly transferred to the CC analytical
column).
5.2 Apparatus
Typical key components and operational stages of atwo-
stage resorption system are presented inFig. 6and Fig, 7.
5.2.1Sampling Device: Low Volume Pump — Intrinsically
safe, portable, battery powered pump (SKC, PA, USA or
5.2.4 Focusing Tube
equivalent make) (see Fig. 3) with a low flow capable of
accurate and adjustable flow control Ier with operating The narrow (typically <3 mm ID) tube containing asmall
range between 5 to 500 ml/min to suck the air sample bed ofsorbent, which ismaintained near or below ambient
with great accuracy in the range of 20-100 ml/min is temperature and used to refocus analytes thermally
required (+2 percent). The time programmable, buiIt in desorbed from the sorbent tube. The focusing trap is
flow.indicator, rechargeable battery operated low flow typically packed with 20 mg of Carbopack’M B (60/80
pump with adjustable run time upto 8hshould bepreferred mesh) and 50 mg of a CarboxenTM 1000-type sorbent
for sampling of BTX. (60/80 mesh).
FIG. 5 SORBENT/SAMPLE TUBES OF STAINLESS STEEL OR (1.ASS FILL-ED
WITH ADSORBINGMATERIAL(TE NAX OR so )AND PROTECHNGCAPS
