a
— eritmaning titrini aniqlash uchun olingan moddaning gramm miqdori;
E — modda ekvivalent massasining g/mol miqdori;
V —
moddani titrlash uchun sarf bo’lgan titrant hajmi, ml.
2. Titri aniqlanayotgan titrant bilan titri aniq bo’lgan eritmani titrlash orqali aniqlanadi:
V
M
V
M
⋅
=
⋅
0
0
V
V
M
M
0
0
⋅
=
M —
titri aniq bo’lgan eritmaning molyarligi;
V —
titri noma’lum bo’lgan eritmaning hajmi;
V
0
— titri aniq bo’lgan eritmaning hajmi.
Titrlangan eritmalar uchun ularni shartli molyarligiga bo’lgan tuzatish koeffitsienti —
К
hisoblanadi.
0
M
M
K
=
formulada
M
0
— titrlangan eritmaning talab etilgan shartli molyarligi;
M —
titrlangan
eritmaning shartli molyarligi.
Aytaylik, M
0
= 0,l mol/l, M=0,102 mol/l bo’lsin. U holda
K
=0,102/0,1 = 1,02 bo’ladi.
Davlat Farmakopeyasi talabiga ko’ra, titrlangan eritmalarning tuzatish koeffitsienti 0,98—1,02
oralig’ida bo’lishi lozim. Agar К talab etilgan qiymatdan farq qilsa, titrlangan eritma quyultiriladi
yoki suyultiriladi. Titrlangan eritmani suyultirish lozim bo’lsa, u holda uning 1 litriga qo’shiladigan
suvning hajmi auvidagi formula bilan hisoblanadi:
1000
)
1
(
⋅
−
=
K
V
formulada
K —
titrlangan eritmaning aniqlangan tuzatish koeffltsiyenti.
Titrlangan eritmaning 1 litrini quyultirish uchun kerak bo’lgan moddaning gramm miqdori
quyidagicha hisoblanadi:
a
K
v
⋅
−
=
)
1
(
a —
1 litr titrlangan eritmani tayyorlash uchun tortib olingan moddaning grammlardagi
miqdori;
v
—1 litr eritmani quyultirib, tuzatish koeffitsiyentini 1 ga yetkazish uchun qo’shilishi lozim
bo’lgan moddaning miqdori.
Titrimetrik usulda aniqlanuvchi moddaning foiz yoki gramm miqdori quyidagi formulalar
yordamida hisoblanadi:
a) to’g’ridan to’g’ri titrlanganda
yoki
b) qayta titrlanganda
yoki
d) nazorat
tajribasi o’tkazilganda
yoki
a
T
K
V
X
100
%
⋅
⋅
⋅
=
a
P
T
K
V
X
gr
⋅
⋅
⋅
=
a
T
K
V
K
V
X
100
)
(
2
2
1
1
%
⋅
⋅
⋅
−
⋅
=
a
P
T
K
V
K
V
X
gr
⋅
⋅
⋅
−
⋅
=
)
(
2
2
1
1
a
K
T
Vn
V
X
100
)
(
1
%
⋅
⋅
⋅
−
=
a
P
K
T
V
Vn
X
gr
⋅
⋅
⋅
−
=
)
(
1
Pharmaceutical chemistry
Autors: Juraeva A.A., Muhitdinova K.Sh., Zaripova N.T. R.A.Xusainova, A.D.Tashpulatova
429
Bunda:
V
— titrlash uchun sarf bo’lgan titrant hajmi;
K
— titrantning tuzatish koeffitsienti;
T
— aniqlanuvchi moddaning g/ml lardagi titri;
V
1
— birinchi titrant hajmi;
V
2
— ikkinchi titrant hajmi;
K
1
,K
2
— tuzatish koeffitsientlari;
V
n
— nazorat tajribasi uchun sarf bo’lgan titrant hajmi;
P
— dori turining massasi.
Keys to’plami.
Keysni bajarish bosqchilari va topshiriqlar:
3.
Keysdagi muammoni keltirib chiqargan asosiy sabablar va hal etish yo‘llarini jadval asosida
izohlang (individual va kichik guruhda).
Muammo turi
Kelib chiqish sabablari
Hal etish yo‘llari
Laboratoriya ishning maqsadi:
Farmatsevtik tahlilda qo’llaniladigan indikatorlar, titrlangan
eritmalar tayyorlash va titrini aniqlash usullari o‘rgatishdan iborat.
Mazmun va kutilayotgan natija:
Trilon B, natriy nitrit, kaliy bromat, natriy tiosulfat, natriy
ishqori titrlangan eritmalarini tayyorlashni o’rgatish. Farmatsevtik laboratoriyalarida miqdoriy
usullarini qo’llashni talabalariga o’rganish.
.
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