Question { BARC, 73996 }

What is entire principle involved in karl fischer titration

Answer

What anil shoukhat had told is good.

The rxn is based on the bunsen reaction between iodine and
sulphur dioxide in presence of a base.Oxidation of sulphur
dioxide by iodine.The rxn is same as that of iodometry
titration.

I2+So2+2H2O--->2HI+H2So4.

Alcohol reacts with sulphur dioxide and a base to form an
intermediate alkyl suphite salt,which is then oxidised by
iodine to alkyl sulphate salt.

H2O+I2+SO2 + 3 C5H5N �� 2(C5H5N+H)I- + C5H5N��SO3
C5H5N��SO3 + CH3OH �� (C5H5N+H)O-SO2��OCH3.

Pyridine is used as a neutrilizing base.In order to shift
the equilbrium to the right of the rxn and to neutralise
the acids produced pyridine is used as the neutralizing
base.

Question { 15906 }

What is mean by peak tailing in case of GC?

Answer

Arumugam thanks a lot bro i got job in a mnc company bcos of the answer posted by you plz give me ur no i had to thank u

Question { 10865 }

what is the use of performing tapped density in
pharmaceutical industry

Answer

Tapped density is used to know the flow ability of the
sample.The flow ability of the sample is importent factor
to determine in pharmaceuticalindustry by determining the
compressibility factor or houser ratio.Samples with better
flow will have ratio nearer to houser ratio 1.

flow ability is importent to determine because the tablet
formation will depend on it.Compresibility factor can also
be known with tapped density.

Bulk density or un tapped density or pour density is the
density of the sample which is un tapped.Where as tapped
density is density the sample occupies after tapping it
mechanically.

There are two methods to determine tapped density.
USP methdod I
USP method II

Tapping is done mechanically by raising the measuring
cylinder and allow it to fall freely under gravity.

density= sample taken/volume it occupies.

Question { Aurobindo, 16628 }

As per OOT for any product what is calculation and how to
invetigate the OOT

Answer

This is only a briefe answer.

OOT means out of trend.

Definition:

In case of routene analysis any result of quantitative
chemical test that do not fall with in the defined band in
comparison to a specification.

Investigation:

Investigation procedure is same as that of OOS(Out of
specification).

OOt result in qc laboratory
.
Report with in 24 hours to qa&supervisor.
.
phase I laboratory investigation is carried out.
.
If any laboratory error is identified then it is termed as
assiagnable cause(ie system problem identified,sample
preparation,dilution in correct,improper transfer of
solvent,analyst etc etc...).There are many check points are
there to investigate.The investigator will go through the
check points.
.
After assiagnable cause identification corrective and
preventive action will be taken,and order for re testing
the original sample or another on same or another equipment
(if system performance is suspected).The person other than
who obtain the initial results should re test the
sample.After re testing results are to be evaluated and
conclude the investigation.

Re testing plan:2 sample preparetions to be done and analyse

Different different OOT limits are there for different
different tests.

For more details mail me.

Question { 12272 }

loss on drying we applied vaccum for some compounds and
some compounds are at 105c why

Answer

Thermally liable compounds are dried in hot air oven.
Thermally un stable compounds are dried under vaccum.
Vaccum is applied to prevent sample loss due to
splashing,foming.Low boiling samples are dried under vaccum.

Question { 21837 }

why we use TLC?

Answer

TLC means Thin layer chromatography.

Chromatography is a seperation techinique.Chromatography
is used to seperate components present in a mixture in to
individual components.Seperation of components is very
importent in pharmaceutical industry to know the nature of
the sample.So,we use TLC.


Uses of TLC :

1.To know the no of components present in a mixture.
2.To choose approprate solvent for column chromatography.
3.To moniter c-c seperation.
4.For reaction monitoring.(during in process of batch)

Procedure&principle:

One or more components are spotted on a adsorbent coated
chromatographic plate and this sample spotted plate is
placed in a solvent ie mobile phase and this mobile phase
is adsorbed by the plate slowly from downwards to upwards
due to capillary action agnist gravitational force.The
components with lower affinity towards mobile phase travels
slowly,and the components with high affinity towards mobile
phase will move faster.Thus components are seperated on a
tlc plate.

TLC PLATE:

The plate is the stationary phase.solvent is mobile
phase.TLC plate is nothing but silica gel like kiesel gel
60F254,silica gel 60F254,cellulose powder is spread on an
alluminium foil,or glass or plastic plate.

We can say more about TLC but not possible to say hear.
Refer web pages,you will get more information

Question { 8853 }

Why we are disodium tartare for factor of karlficher
titration ?

Answer

First of all DST is a crystallin hydrate.

Dst is used in factor determination using karl fischer
titration bcos....

1) It absorbs precise amounts of water.
2) It contains therotically caliculated water content.
ie.. 15.66% of water.Water content in dst is constant
in more cases,ie it can with stand small changes in
climatic and temp changes in laboratory.
3) Easily available in market with 100% purity in reagent
grade.And it is a primary standard too.

Question { Lee Pharma, 24871 }

What is meaning of audit trail in hplc

Answer

Audit trail is regulatory requirement.Pass word procted.

Audit trails will gives us accountubility.The auditor will
clearly identifies what had happened by observing audit
trails.

Audit trail will keeps a record of all the changes we do ie
deleting,correcting,editing the data.Software log ins and
log outs.System shut downs and start ups.Method changes,
errors occured etc.

Audit trails will not be attributed to hplc only.It can be
used for other instruments also like gc,ir,uv etc... if the
software we are using permits.

we can say more about audit trails but i explained briefly.

Question { Enaltec Labs, 22251 }

What is the difference between kf  and LOD

Answer

Your answer is correct Mr.Ashok but you should alobrate it.
Coming to babu1029 answer what about water when we perform LOD at 60 degrees c ?