Clinical chemistry
Solution
Is combination solute and solvent. The dissolved is
called solute and the most of time the substance
present in large is called solvent.
Note:Reagent:-Can be applied in particular to any
chemical compound or mixture of compound
usually in solution , used in chemical analysis or for
detection of biological constituent.
Stock solution:-Is concentrated solution from which
different types of working solution can be prepared
by simple dilutions.
Types of solution:
(1)Molar solution.
(2)Normal solution.
(3)Percent solution.
(4)Buffer solution.
(5)Standard solution.
(6)Physiological solution.
(7)Other complex reagent.
Molar solution
Is gram molecular weight dissolved in one litre of
solvent.
How to prepare?
Note:
M.Wt.=is sum of automatic weight of element
compound.
EX:-Na OH
23+16+1=40
To prepare molar solution use the formula
Required mol/l X M.Wt
EX:To make one liter of sodium chloride "Na Cl"
M.Wt.=58.5
1 x58.5=58.5
EX:-0.5M of Na OH
0.5 X40=20g/l
Preparation of molar solution of acid:M=
Purity S .G 1000
M . Wt . 100
EX:Prepare 1M HCl
Purity=36.5
S.G=1.18
M.Wt=36.5
36.5 1.18 1000
=11.8 M
36.5 100
Normal solution
Is gram equivalent weight dissolved in one liter of
solvent
Equi Wt=
M . wt
Valence
Ex:Prepare normal solution of Na OH
Equi Wt.=
M .Wt 40
=
V
1
=40g/l
Ex:-one normal Na2CO3
2X23+14+16X3=138
Equi wt.=
132=8
=69 g/l
2
Buffer solution
Is a solution that resist change pH on addition of
acid and alkali.
Buffered solution prepare by:1. Weak acid and its salt , ex:-H2CO3+HCO3(lactic
acid)
2. Weak base and its salt , ex:-NH3+Di hydrogen
phosphate (monohydrate)
3. Acid salt and base salt , ex:- Dihydrogen
phosphate mono hydrogen phosphate
Ammonium-Ammonia
Percentage solution
X g in 100ml at solution
*can be prepared by three ways:A.Weight/volume(W/V):
Common type
Ex.20% NaOH
20g/dl
By sensitive balance , weight 20 gram of Na OH
dissolved in 50-70ml D.W then complete 100ml by
measuring cylinder.
Ex:- 0.9 Na OH
0.9g
100ml
B.Volume/Volume(V/V):
It's a dilution of one stock solution by other solvent
and total volume based on 100ml.
Ex:250ml of 10%Hcl
10
100
250
X=
X
10 X 250
=25 ml
100
25ml HCl
250D.W
Ex:-1% acid alcohol
1ml acid HCl+99ml70% alcohol
C.Weight/Weight(W/W):
Ex:Prepare 68%W/W carbonate buffer solution from
40% Ca CO3 and HCO3.
Weight 68g from 40% Ca CO3 in beaker and add
carbonic acid to complete to total weight to 100g.
Standard solution
Know concentration
A.
Primary STD:
Is highly purified chemical that can be measured
directly to produce substance of exact known
concentration.
I.
Stable , stay to obtain , dry and preserve in
pure state.
II. Large molecular weight.
III. Not altered in air during weighting (absorbed
moisture).
IV. Readily soluble in the solvent.
B.
Secondary STD:
Is a substance of lower purity whose concentration
is determined by comparison with a primary STD.
Note weight ex:-HCl , nitric acid
Must be first prepared to an appropriate
concentration and tired against a primary
standard.
C.Complex Reagent:
These reagent prepared by resolving more than
one chemical in the solvent. The various chemical
used should not be added together but are added
one after another by dissolving each chemical
separately.
EX:-Benedict's , Biuret.
Normal saline
Refers to physiological saline (0.85%) isotonic with
body fluids.
Expression of concentration
Concentration of analyze in solution can be
expressed in many ways:
A. Morality: number of moles in one liter.
One mole of substance equal g/M.Wt.
1g/l=1mol/L
Mol/L
M.Mol/L
Micro Mol/L
N.Mol/L
B. Normailty:
Number of grams equivalent Wight per 1 liter
Equi=
M .Wt
V
C.Percentage %.
Equal to parts per hundred or the amount to total
units of solution three ways:
I.
W/V
II. W/W
III. V/V
Note:
Concentration of molar solution into normal
solution
M=
N
V
N=M x v
If valance is one mono valance
M=N
Conversion of percentage solution in Mol/L
solution
g%=
g /dl 10
M .Wt .
Ex:- Convert 4% Na OH in Mol/L solution
4 10
=1
40
Therefore 4% W/V Na OH is the esurient to 1Mol /
L Na Oh solution.
Ex. To convert 0.9% W/V Na Cl
0.9 10
58.5
=0.15M.Mml
Dilution
To reduce concentration.
Dilution factor =
Total volume
Volume added
EX:-0.1/1.4
0.1+1.4 1.5
1
=
=15=
0.1
0.1
15
Type of dilution
1. M1 X V1 = M2X V2
Using
RV
O
2. Serial dilution
Progressive dilution multiple ranging from more
concentration to less concentration solution.
Are useful when volume concentrate is short
supply need to minimized.
EX:- Serum of pediatric
Total volume
Dilution factor
1ml
+
Concentration
1ml
1ml
1ml
1/2
1/4
1/8
1/16
Initial dilution factor X Next dilution final dilution
factor
Systemic International Units
SIU
System need to express result or volume
:We have two types
1. Old unit.
2. New unit.
Derived as
Base Unit
Mole
Meter
Kilogram
Second
Symbol
Mol(m)
m
kg
s
Used of SIU
- Test method.
- Preparation of reagent.
- Reporting of result.
Important:
1. One universal unit is need.
2. To get rid of chemical.
Measured
Amount of
substance
Length
Mass
Time
3. Avoid wrong calculation.
4. To prepare STD of low concentration.
SIU prefixes
To enable the measurement of quantities large or
smaller than the base unit
EX:Prefix
Symbol
Factor
dice
d
X 10-1
milli
m
X 10-3
micro
X10-6
nano
n
X10-9
pico
p
X10-12
femto
f
X10-15
Volume:
SIU cubic meter
liter
By L or multiples and sub multiples of liter
One liter
1000ml
Old unit
SIU
100ml
dl
cc
ml
L
dlX10
ml
dl/100
dl=mlX100
Weight:
old
Kilogram
gram
mgm
nanogram
1Kg=1000g
1g=1000mg
Amount of substance(mol)
Ig/L=1mol/L
SIU
Kg
g
mg
ug
1mg/l=1m.mol/L
Conversion of old units in SIU
1. Protein:
Substance
Plasma protein
Urine protein
Old units
g/dl
Mg/dl
SIU
g/L(X10)
g/day
(urine volume)
100000
C.S.F protein
Mg/dl
g/l(
2. Glucose , urea ,calcium ,triglyceride ,
cholesterol (m.mol/)
mg/dl10
M . wt
m.mol/L=
mg/dl=
100
M . wt . m. mol /l
10
3. Creatinine , bilirubin(mol/l)
mg/dl 1000
M . Wt .
Conversion factor for:
10
180
- Glucose=
- Urea=
10
60
=0.055
=0.166
- Uirc acid=
10
168
=0.059
4. Electrolyte(m.mo/l)
5. EX:- Old unit:
mequl
volume
- SIU:m.mol/l
6. Enzymes:
Old unit depend on name of the method king and
jingd/100ml
EX:- - ALP
- amylae
but now using katal is the amount of enzymes
which cataylsis one mol of substance per second or
1/l.
catalyze one micro mol of substance per min.
