About limit test on sulphate

1. LIMIT TEST ON
SULPHATE
PRESENTED BY : UNDER GUIDANCE OF:
KEERTHI.NEELU FOR V.MOUNICA MAM M.PHARM
1ST PHARM.D DEPARTMENT OF PHARMACEUTICAL ANALYSIS
Y17PHD0411 HINDU COLLEGE OF PHARMACY
HINDU COLLEGE OF PHARMACY

2. Contents :
 Definition of Limit test
 Types of factors accomplished
 Types of factors accomplished by Control of Personal Errors
 Apparatus required for limit test on sulphate
 Chemicals required
 Preparation and Procedure
 Observations and Result’s
 References

3. LIMIT TEST : They are quantitative or semi
quantitative tests designed to identify &
control small quantities of impurity which
are likely to be present
The design of individual tests is therefore
important if errors are to be avoided in
hands oh different operators
These are accomplished by giving attention
to a number of factors. They are
1.Specificity of tests
2.Sensitivity
3.Control of personal errors

4. 1.Specificity of tests :Any test used as limit test must necessarily give
some form of selective reaction with trace impurity. A test may be
demanded which will exclude one specific impurity ,but highly
specific tests are not always the best; a less specific test which limits
several likely impurities at once is obviously advantageous & it can
be accomplished
For Example : Heavy metals test is applied to alum which not only
limits contamination by lead , but also other heavy metal
contaminants precipitated by thioacetamide as sulphide at pH 3.5.
2.Sensitivity :Degree of sensitivity required in limit test varies
enormously according to standard of purity demanded by
monograph. Sensitivity of most tests is dependent upon a number of
variable factors all capable of strict definition , and all favourable
towards production of reproducible results. Thus precipitation of an
insoluble substance from solution is governed by such factors
 Concentration of solute & of precipitating reagent
 Duration of reaction
 Reaction temperature
 Nature & concentration of other substances unavoidably present in
solution

5. 3.Control of Personal Errors : It is essential to
exclude all possible sources of ambiguity in
description of a test . Vague terms such as “
Slight precipitate” should be avoided as far
as possible . Extent of visible reaction to be
expected under specified test conditions
should be clearly and precisely defined . This
is usually accomplished in one of three ways
A. Tests in which there is no Visible reaction
B. Comprison methods
C. Quantitative determinations

6. 1.Tests in which there is no visible reaction : A definite
statement is incorporated in wording of test , which
states that there shall be no colour , opalescence or
precipitate , whichever is appropriate to particular test
.
For Example : This type of requirement is test for barium
and calcium in Dilute Hypophosphorus . Acid ( BP
Appendix 1) where additions of dilute sulphuric acid
under precisely controlled condition shall produce ‘ no
turbidity , or precipitate ’within 1 hour . The time
factor is used here means of increasing sensitivity of
test .
Tests which give negative results don’t necessarily imply
complete absence of impurity .

7. 2.Comprison methods : Test of this type
require a standard containing a definite
amount of impurity , to be set up at same
time & under same conditions as test
experiment. In this way extent of
reaction is readily determined by direct
comparison of test solution with a
standard of known concentration.
Official limit tests for chlorides ,
sulphate , iron , heavy metals are based
on principle.

8. 3.Quantitative determinations : Quantitative determination of
impurities is only applied in special circumstances , usually in
those cases where limit is not readily suspectible to simple &
more direct chemical determination .
This method is used in following different types of test :
I. Limits of insoluble matter
II. Limits of soluble matter
III. Limts of moisture , volatile matter , and residual solvents
IV. Limits of non-volatile matter
V. Limits of residue on ignition
VI. Loss on ignition
VII. Ash values
VIII.Precipitation methods

10. APPARATUS :
 Nessler’s cylinder , Glass rod

11. Measuring cylinder , Pipette

12. Dropper , Rubber stopper

13. Chemicals required : Barium sulphate reagent
0.05 M Barium chloride solution
is prepared by dissolving 12 gm
of barium chloride in 1000 ml of
water, to the 15 ml of the above
solution add 55 ml of water , 20
ml of alcohol and 5 ml of
0.0181% w/v solution of
potassium sulphate and the final
volume was made up to 100 ml

15. Preparation of ethanolic standard solution
( 10 PPM ) )
Dilute 1 volume 0.1089% w/v
solution of potassium sulphate
in
Ethanol (30%) to 100 volumes
with ethanol (30%)

16. Preparation of sulphate standard
solution (10PPM )
Dilute 1 volume of a 0.1089%
w/v solution of potassium
Sulphate in distilled water to
100 volumes with distilled
water

17. Procedure:

19. Observation : The turbidity produced
in the test solution is lesser than
standard solution
Inference : Given substance
passes limit test for sulphate as
per Indian Pharmacopeia
when compared with that of a
standard substance .
FOR SAMPLE – 1 PASSED SAMPLE

20. FOR SAMPLE – 2 FAILED SAMPLE
Inference : The given substance fails
the limit test for sulphate as per Indian
Pharmacopeia when compared with
that of a standard substance .
Observation :The turbidity
Produced in the test solution
Is more than standard solution

21. REFERENCES :
1. www.webformulas.com
2.www.srmuniv.ac.in/sites/def
ault/files/downloads/Limit
Test.pdf
3.www.ffcr.or.jp/zaidan/ffcrho
me.nsf/…/$FILE/B38.pdf

22. THANK YOU