gzb course presentation
TRANSCRIPT
Ambient Air Quality Standards of Notified Parameters and Range of Analysis in Methods Recommended
S.No. Parameters Applicable Standard Range of the Analytical Methods
1. SO2 50 g/m3 (6 g/m3 to 1025 g/m3)
2 NO2 40 g/m3 (9 g/m3 to 900 g/m3)
3 NH3 100 g/m3 (20 g/m3 to 700 g/m3)
4 O3 100 g/m3 (20 g/m3 to 20,005 g/m3)
5 Pb 0.5 g/m3 (0.01 g/m3 to 2.5 g/m3)
6 Ni 20 ng/m3 (5 ng/m3 to 1000 ng/m3)
7 As 6 ng/m3 (100 ng/m3 to 1500 ng/m3)for 10 m3 sample
8 CO 2000 g/m3 (1144 g/m3 to 114400 g/m3)
9 Benzene 5 g/m3 (1g/m3to10mg/m3)
10 Benzo(a)pyrene 1ng/m3 (3 ng in extracted sample LDL)
Benzene Analysis
Capilliary Column 624 having coating Cynopropyl Pheylpolysiloxane length 30m, ID-0.25mm coating thickness 1.4 mm – 1No.
CS2 Benzene free – 500ML Benzene (Chromatography Grade) – 250ml We will be sending ultrasonically extracted samples for analysis of
Benzene at your set up for its analysis. We suggest following conditions to be set on GC while analysis A
N2 gas flow – 30ml/min H2 gas flow – 30ml/min Air flow - 300ml/min
B. We need to inject at least 5ul sample or 10 ul sample C. Set injection port temp – 250 oCD Set FID Temp - 300oC
Benzo(a)pyrene Four circles of 3.6cm diameter are cut from exposed filters These are kept in 30ml micro Soxhlet apparatus on glass wool (to prevent
carbon particles going in to solvent) Put 30ml fluorescence free Cylohexane Extracted solvent is evaporated to 2ml in current of nitrogen This 2ml extract is send to lab for analysis of Benzo(a)pyrene Analysis is done after passing extract through a chromatographic column
12cm long prepared by slurring activated alumina with toluene. Elution is carried out using toluene. Collected elutant is air evaporated and final volume is made as 5ml in toluene
Fluorescence emission measurement of peak heights are now made at 307 & 387nm using Fluorimeter
Blank filter paper is also run as above Standard is analyzed and peak heights are obtained for various range of
concentration and a calibration graph is prepared. Obtained peak height of sample is used to find out concentration of
Benzo(a)pyrene with the help of calibration curve.
Area taken for analysis 40.7 cm2 Total Exposed Area of filter 406.5cm2Area factor for multiplication 406.5/40.7 = 9.99 say 10
Solvent Extraction of Benzo(a)pyrene followed by HPLC/GC analysis
Soxhlet Apparatus GC, Capillary Column
Water In
Water Out
Condenser
Flask
sSample
Solvent
Heavy Metals Pb,Ni and As in Particulates Collected on Glass Micro Fiber Filter Paper From
Ambient Air
It is desirable to take 24 hrs sample of Particulates on 8 x10’’ Filter Paper Extraction of filter paper:
Take a strip of exposed filter as 2.5 x 17.5cm for urban sample 5.0 x 17.5cm for rural sample
This strip need to be ashed in low temperature asher (If not available leave the filter in oven at 250oC for 1hr at least
Transfer ashed filter in extraction tube Take 125ML Erlenmeyer flask with 24/40 female Joint . Put 8mL concentrated HCL and
32ML 40% HNO3. Attach this flask to extraction tube and connect a Allihn condensor and reflux it for 3hrs
Now remove the extraction tube condenser. Extracted liquid is evaporated on hot plate till volume is reduced to about 2ML
Leave the contents overnight for cooling . Now transfer the contents to 15ML centrifuge (2000 rpm) tube with 3 washing by 5-10
drops by 1:20HCI for 30 minutes Transfer supernant liquid in the polypropylene tube with cap and send to AAS for
analysis. Dilution of this sample may be done using 1:10 HCI as per requirements. For analysis of Arsenic Hydride Converter is required with AAS fitted with Graphite
Furnace..
Analysis of Arsenic in particulates Collected from Ambient Air Range: Concentration as low as 0.1 g/m3 or 100ng/mg can be
measured in 10m3 sampled air Since limit of arsenic is 6ng/m3 it is difficult to analyzed the
arsenic concentration in such low concentration for small duration sample.
For Arsenic sampling duration need to be 24hrs 8hrs sample must not be analyzed.
Arsenic present in particulates as Arsenic Oxide and arsenate Particulate are dissolved in HCI. Extract is made to react with KI
and SnCI2. This give trivalent arsenic. This trivalent Arsenic is reduced to Arsine (ASH3) by Zinc in
acidic solution in Gutzeitt generator. This Arsine is passed through H2S scrubber which contain glass wool impregnated with lead acetate and then into absorber containing silver diethyl thiocarbamate dissolved in pyridine. Here reaction take place and red soluble complex is formed which is directly proportion to the Arsenic. Intensity of this colour is measured at 535nm.
Analysis of Arsenic in particulates Collected from Ambient Air Extraction of Filter
Take filter strip 2.5cm x 17.5cm in flask. + 6N HCI digest 90.95oC on water bath for 1hr. Cool and add 6N NaOH. Now add 1ML KI and 8 drops of stanus chloride and mix. Allow 15 minute for reduction of Arsenic in Trivalent state. Cool solution in ice bath at 4oC Impregnate glass wool with lead acetate. 15ML lead acetate is good for 4cm length of glass wool.
Take 3ML of silver diethyl thiocarbamate solution in absorber tube. Add 3gm of Zinc to the flask and immediate connect to scrubber-absorber assembly allow 90minute for complete evolution of Arisen gas. Color will form which is directly proportional to the concentration of Arsenic. Blank should also be handled in the also above. Read absorbance against blank at 535nm.
Ozone Range 0.01 to 10PPM Absorbing Solution:
13.6gmKH2PO4+14.2gm Na2HPO4 +10gm KI make up contents up to 1000cc by distilled water. Adjust pH 6.8 . Leave solution in dark place overnight before use.
I2 Stock: 0.025M(0.05N)Dissolve 16gm KI and 3.173gm of I2 and
make up this by distilled water up to 500ML. I2 working 0.001M
Take 4ML of 0.025 M I2 in 100mL flask and dilute it with absorbing solution up to the mark
Calibration Curve Preparation Take 4.09 mL 0.001 M I2 solution and dilute it up to
100mL using absorbing solution this will be 1ulO3/mL
Take 10ML flask and put 1mL 2mL 3mL 5mL 8mL 10mL solution and make up to 10mL using absorbing solution
Read absorbance at 352nm against distilled water and plot the calibration curve
Analysis Read absorbance of exposed sample against blank and
find out concentration of 03ul/mL
Making of SO2 Trap for Ozone sampling Take glass micro fiber filter 8*10 inches and cut a
piece of 400 cm2 Drop 15 ml aqueous solution of 2.5gm chromium
trioxide mixed with 0.7 ml conc. H2SO4 Dry this in oven at 90 degrees for 1 hour Quickly cut circles of 6mm dia and store in airtight
glass bottle. Fill these circles in trap after filling glass fibers just
before sampling.
CALCULATION cal factor x 48 x 1000 x 25
O3 (ug/m3) = --------------------------- Vol. of air (lit) x 24.45 x 10
Thank you