Yes, you are missing two parameters (and some background information), the volume of air sampled (the m3) and the fractional volume of extract analyzed (the uL). Presumably you are trying to measure the concentration or mass (of what, particulates, particle bound small molecules, elements, spores...) in the air. Presumably you are using an instrument response to these analytes in extracts or concentrates of the quartz fiber filter (you described calibrations of ng/uL).  So you need to determine the volume of air sampled for each QFF (typically 100-700 L/min, but unique to each instrument/set-up), and the fractional volume of extract from that QFF that was injected into the instrument.  For example, many trace organic air sampling campaigns will sample air for 12 hrs at ~600L/min or 432000L or 432 m3. Extracts from these samples might be concentrated to 1 mL and 1 uL of that might be injected onto a GC. Thus 1uL/1000uL is the fraction of the sample (extract) analyzed and 432 m3 was the sample so the conversion factor is 0.432 m3 air/uL injected. This is just a hypothetical scenario. Your samples will each have their own air volumes and fractions analyzed.

Dear Sarika

As long as your unknown concentration of pollutant (you don't especify which one it is) falls within the range of the calibration curve, you should have no problem in expressing your concentration in ng/m^3 by just converting from ng/uL (by just multiplying by a factor of 1x10^9). On the other hand, you have to bear in mind that, in case you have a gaseous pollutant, you have to consider the following equation (derived from the ideal gas law):

ug/m^3 = ppm x 40.9(MW)

Where ppm is the concentration of the pollutant in parts per million, and MW is the molecular weight of the pollutant in g/mole.

You can consult Finlayson-Pitts, B. J. and Pitts, J. N., Jr. Chemistry of the Upper and Lower Atmosphere. Theory, Experiments, and Applications. Academic Press, 2000 for further information.

Dear Sarika, I agree with Luke, you need air volume sampled and injection volume in the analytical equipment. Dear Gerardo, it's not possible to convert directly from ng/ul to ng/m3 because the sample injected in the instrument is a liquid containing the analyte extracted from the filter, and the sample is the air passed through the filter for a given time. Best regards.

Eduardo Gerardo

This is the classical confusion of ppb in liquid phase versus that in atmospheric units

I fully agree with Luke.  I realise I didn't give a proper answer as I was in a rush. I hope I didn't confuse Sarika. 

thanks everyone for responding.............thanks Luke,you have given a proper approach.

But Luke tell me one thing please......as i have not done extraction as i used TD-GC/MS in which direct a portion of QFF is inserted in TD-Tubes so how would i calculate Fractional Vol of Extract.Please suggest.........

In this case, you are measuring in the instrument the analyte mass captured in the area of the piece of filter you inserted in the TD-GC/MS. If you assume that the analyte is homogeneusly distributed on the filter, you may calculate the total mass of analyte in the sampled air multiplying the measured mass of analyte by the following factor: total exposed filter area / area of the piece inserted in the TD-GC/MS

thank you Eduardo

Eduardo

I think it is Always advisbale to do this in triplo if it is the first time that is take three pieces from the filter say one att he center one at the outer rim and depending on outcome a third either center or outer rim

You may Calculate in Two ways 

1) Single Standard Calculation 

2) Multi point Calibration Calculation 

As u may inject the standard in GC MS  and u may got the peaks ind integrate to get the peak area for the particular component in a different Concentration leaves

and u can plat a Calibration graph by using Excel Sheets 

Concentration Vs Area of the individual components

Con in ppm (or mg/l or Micro gram/ml or ng/micro gram  all are same ) thins in X axis

area of the components in Y axis

for eg

 Con In ng/MicL           area

1                           225         

5                          1224

10                        2354

20                        4755

40                        9625

FROM THIS LINEARITY YOU will get the Stright line Y = mX+C

from thar u calculate the content in sample in ng/micg 

Sample content ng/m3=  Samp Con in ppm X Final mackup volume in ml  X 1000 (ng/m3)

or 

single standard calculation 

 Con in ng/m3                          Sample peak area  X Std Con in ppm X mackup volum of sample in ml *1000

                                           Standard peak area  X Volume of air sampled in m3

sa

                                                                 Volume of air sampled in m3

Hi Sarika,

You have to calculate the amount of compound in nanogram for the whole filter. And then you have to divide the calculated amount by air volume (m3) which passed through the filter.