254
6 Quantitative Aspects of Analytical Chemistry
(Mass units)
EXPRESSION OF A
RESULT IN
QUANTITATIVE ANALYSIS
Box 6.1
g/mL (g); giL (kg)
mg/mL (g); mg/L (kg)
ng/mL (g); ng/L (kg)
mol/l (kg); Ilmol/L (kg)
Mass and Volume Unit Scales
~ k9
9
mg
I
I
I
cJ
U
l.J
E r L
mL
~L
Fig. 6.5. Common ways of expressing
results in Quantitative Analysis
\1g
I
L
nL
W-IL
1O " .. ~ ... g
/~
l06. 0ng / .
101 ilL
1I) l o mg
Example: The result of a CMP for determining traces of a pesticide in water is 3.10 ng/l. lf the
density of the water at a given temperature is known (c) = 1.024 kg/L), the proper way of
expressing the result will be in ng/kg (mass Imass) :
ng
L
Result = 3.10 - - - = 3.03 ng/kg
L 1.024 kg
In addition, a relative result can be delivered as a concentration (the mass or
moles of analyte per unit sample volume or mass), which can be expressed in a
6 Quantitative Aspects of Analytical Chemistry
(Mass units)
EXPRESSION OF A
RESULT IN
QUANTITATIVE ANALYSIS
Box 6.1
g/mL (g); giL (kg)
mg/mL (g); mg/L (kg)
ng/mL (g); ng/L (kg)
mol/l (kg); Ilmol/L (kg)
Mass and Volume Unit Scales
~ k9
9
mg
I
I
I
cJ
U
l.J
E r L
mL
~L
Fig. 6.5. Common ways of expressing
results in Quantitative Analysis
\1g
I
L
nL
W-IL
1O " .. ~ ... g
/~
l06. 0ng / .
101 ilL
1I) l o mg
Example: The result of a CMP for determining traces of a pesticide in water is 3.10 ng/l. lf the
density of the water at a given temperature is known (c) = 1.024 kg/L), the proper way of
expressing the result will be in ng/kg (mass Imass) :
ng
L
Result = 3.10 - - - = 3.03 ng/kg
L 1.024 kg
In addition, a relative result can be delivered as a concentration (the mass or
moles of analyte per unit sample volume or mass), which can be expressed in a