Question

3. a sample shows a total carbon of 3.6 mg/l. After it is purged with nitrogen for an hour, the new total carbon measurement is 2.9 mg/l. When another aliquot is acidified, purged with nitrogen and then analyzed, the total carbon is 2.3 mg/l. What is the concentration of purgeable organics, non-purgeable organics and of inorganic carbon?

Answer 1

Total carbon content in a given sample is 3.6 mg/L.

Aliquote is purged with N2 gas, new total carbon content=2.9 mg/L

i.e. 3.6-2.9=0.7 mg/L

0.7 mg/L of the carbon converted into inorganic carbon such as CO₂ or H2CO3.

Hence, concentration of the purgeable organic=2.9 mg/L, becuase 2.9 mg/L is still present in the aliquot which can be purgeable.

Concentration of inoranic carbon = 0.7 mg/L, because 0.7 mg/L is converted into inorganic carbon viz. CO2 and H2CO3 as mentioned above.

Amount of the non-pugeable organic=2.9 mg/L, because 2.9 mg/L is remained evenafter purging.

In case of another aliquote (acidified aliquote) which is purged with N2:

Total carbon content in a given sample is 3.6 mg/L.

Aliquote is purged with N2 gas, new total carbon content=2.3 mg/L

i.e. 3.6-2.3= 1.3 mg/L

1.3 mg/L of the carbon converted into inorganic carbon such as CO₂ or H2CO3.

Hence, concentration of the purgeable organic=2.3 mg/L, becuase 2.3 mg/L is still present in the aliquot which can be purgeable.

Concentration of inoranic carbon = 1.3 mg/L, because 1.3 mg/L is converted into inorganic carbon viz. CO2 and H2CO3 as mentioned above.

Amount of the non-pugeable organic=2.3 mg/L, because 2.3 mg/L is remained evenafter acidification and simultaneous purging.