|
|
Continued
…
Appendix V
Simplified
classification of goiter
______________________________________________________________________
Grade
0 : No palpable
or visible goiter
______________________________________________________________________
Grade
1 : A mass in
the neck that
is consistent with
an enlarged
thyroid that is
palpable but not visible (PNV) when the neck
is in
the normal position. It moves upward in
the neck as
the
subject swallows.
Nodular alteration(s) can
occur even
when the
thyroid is not visibly enlarged.
Grade 2 : A swelling in the neck
that is
visible (V) when the neck is in a
normal position
and is consistent
with an enlarged
thyroid when
the neck is
palpated.
________________________________________________________________________
Epidemiological
criteria for assessing the severity of IDD based
on
the prevalence of goiter in school age children
Prevalence of goiter Mild IDD Moderate IDD Severe IDD
_________________________________________________________________
Appendix
VII
Epidemiological
criteria for assessing severity of IDD
based
on median urinary iodine levels
________________________________________
Median value Severity of IDD
________________________________________
< 20 Severe IDD
20-49 Moderate IDD
50-99 Mild IDD
> 100 No deficiency
________________________________________
Appendix VIII
IDD
prevalence in districts of Andhra Pradesh, Karnataka, Kerala and Tamil Nadu
states of India as per the survey conducted by DGHS, Government of India
Survey district Prevalence rate
|
1. |
Andhra
Pradesh |
|
|
1986 |
Srikakulam |
12.6 |
|
1986 |
Vizianagaram |
9.2 |
|
1985 |
Visakhapatnam |
34.7 |
|
1985 |
Godavari |
64.4 |
|
1985 |
Khammam |
42.0 |
|
1985 |
Adilabad |
54.0 |
|
1986 |
Warrangal |
30.0 |
|
2. |
Karnataka |
|
|
1986 |
Chickmaglur |
41.11 |
|
1989 |
Kodagu |
23.1 |
|
1989 |
Uttar Kannad |
10.67 |
|
1991 |
Shimoga |
|
|
1989 |
Dakshin Kannada |
14.3 |
|
3. |
Kerala |
|
|
1984 |
Eranakulam |
44.47 |
|
1990 |
Thiruvanthapuram |
17.0 |
|
1991 |
Idduki |
17.9 |
|
1991 |
Kollam |
9.3 |
|
|
Pathanamthitta |
12.67 |
|
|
Kottayam |
21.0 |
|
|
Thrisur |
14.0 |
|
|
Manjeri |
11.0 |
|
|
Calicut |
18.0 |
|
|
Wayanad |
21.0 |
|
|
Kannur |
11.0 |
|
|
Kasargod |
10.0 |
|
4. |
Tamil Nadu |
|
|
|
Nilgiri |
6.9 |
|
|
Tirichirapalli |
32.9 |
|
|
Madurai |
18.0 |
|
|
Dindigul |
28.0 |
Appendix IX
Profile of IDD and production
of iodised salt in Andhra Pradesh
IDD Prevalence
Surveys conducted in 10 out
of the 23 districts have revealed 9 districts to be endemic to IDD, with goiter
prevalence rates from 9.2 to 64.4%.
Status of Ban
The state government has
issued a notification banning sale of salt other than iodised salt in the
entire state vide Go Ms No. 290 dated 6.6.94 which was to come into force from
1.1.1995. However, the ban order was withdrawn following filing of Writ
Petitions by a section of manufactures, traders, etc. Subsequently, vide
notification No. 117 dated 24.4.95, sale of non-iodised salt was prohibited in
7 districts Viz., Srikakulam, Vizayanagarm, Visakhapatnam, East Godavari,
Khammam, Warangal, and Adilabad
IDD Cell
An IDD Cell was established
in the Directorate of Health Services in 1987 to monitor the progress.
Subsequently, during 1994, district and state level committees were constituted
for periodical monitoring of supply & quality of iodised salt.
Requirement and Supply of
Iodised Salt
Andhra Pradesh is the 4th
largest salt producing State in the country, with an average annual production
of about 2.6 lakh tonnes. The remaining requirement of the state for edible and
industrial uses is mainly met from Tamil Nadu. Linkage for movement of salt has
been provided to the state in the zone scheme from Gujarat and Chennai zones.
Iodisation Capacity and
production
75 salt iodistation plants with
an installed capacity of 7.55 lakh tonnes
including one salt refinery have been established in the state.
Salt Department with the
financial assistance of UNICEF has donated 12 salt iodisation plants to the
Small Salt Producers Association and Cooperative Societies in the state along
with potassium iodate to enable them to iodise their produce
Quality Monitoring
To monitor the quality of
iodised salt at production sources, Salt Department has established three
laboratories at Chinnaganjam, Kakinada and Naupada. The details of samples
analysed during the last three years as follows:
|
Year |
Samples analysed |
Found standard |
|
1998 |
604 |
536 (88.7) |
|
1999 |
541 |
407 (76.2) |
|
2000 |
285 |
282 (98.2) |
Appendix X
Profile of IDD and production
of iodised salt in Karnataka
IDD Prevalence
Surveys conducted in 17 out
of 27 districts in the state revealed 6 districts to be endemic to goiter.
Ban Notification
The Govt. of Karnataka has banned
the sale of salt other than iodised salt for edible purposes in the entire
state with effect from 28.2.1996.
IDD Cell
An IDD Cell is established in
the State Directorate of Health services. This cell is undertaking IEC
activities, training of peripheral health workers, etc. besides
conducting goiter surveys.
Iodisation Capacity
Five iodisation plants with
an total capacity of 32,000 tonnes per annum have been set up in the salt
producing district of Dakshin Kannada. However, their actual production during
the year 2000 was only 4,000 tonnes.
Requirement and Supply of
Iodised Salt
Although the State is
bestowed with a long coast line, salt production is confined to few pockets in
Dakshin Kannada district due to unfavourable weather conditions. The average
annual salt production is about 10-15 thousand tonnes. Therefore, the entire
requirement of iodised salt (3.22 lakh tonnes) is mainly met from Tamil Nadu.
Some quantity of salt is also procured form Gujarat & Maharashtra.
Supply of iodised salt during
the last 3 years was as follows :
Karnataka State has been
provided linkages in the Zonal Scheme from Gujarat, Mumbai and Chennai Zones.
The state government has set
up a coordination committee under the Chairmanship of secretary health. The committee regularly
meets and reviews the progress of NIDDCP. Besides, interaction meetings are
also organized at regular intervals with buyers, sellers and other stake
holders to identify the problems relating to availability and price of iodised
salt.
Appendix
XI
Profile of IDD and production
of iodised salt in Kerala
IDD Prevalence
Surveys conducted by
state/central government from 1989 to 1994 in 14 out of 20 districts of the state
have revealed that 11 districts were endemic to goiter. The prevalence rate
ranging from 4.7 to 27.3%.
Ban Notification
Although 11out of the 14
districts in the state were found to be endemic, the state government has not
yet prohibited the sale of non-iodised salt.
IDD Cell
IDD Cell has been established in the state health
directorate.
Requirement and Supply of
Iodised Salt
The annual requirement of
salt for edible purpose is estimated to be at 2.08 lakh tonnes. Kerala is a
coastal state but the climatic conditions are not favourable for salt
production hence, the state is procuring its entire requirement of salt from
Tamil Nadu.
Appendix
XII
Profile of IDD and production
of iodised salt in Pondicherry
IDD Prevalence
Although no systematic survey
has been undertaken in U.T. however, goiter cases have been reported.
Status of Ban
The U.T. administration has
banned the sale of non iodised salt with effect from 1.9.1997.
IDD Cell
The U.T. administration has
not yet set up IDD Cell to monitor the NIDDCP.
Requirement and Supply of
Iodised Salt
The total requirement of
iodised salt for the U.T. is estimated to be 5,784 tonnes per annum. Salt is
procured from Tamil Nadu.
The State Civil Supplies Corporation, M/s PAPSCO is
selling iodised salt @ Rs. 2.60 per kg. to the people below poverty line,
through 29 fair price shops in Pondicherry and Karaikal region on "no
profit-no loss" basis under centrally sponsored "Sarvapriya
Scheme", on experimental basis. This salt is being supplied by NCCF.
Monitoring Information
System.
Food and drug authority
collects salt samples from traders and retailers for testing in public health
laboratories. The details of results of salt samples tested are given below:
|
|
Beneficiary level |
Trader level |
|
Samples tested |
201 |
29 |
|
<15ppm |
138
(69%) |
21
(72.4%) |
|
>=15ppm |
63
(31%) |
8
(27.6%) |
Appendix XIII
Profile of IDD and production
of iodised salt in Tamil Nadu
IDD Prevalence
Survey conducted in all the 29 districts
revealed prevalence of goiter in all the districts. However, only 18 districts
have been found to be endemic with a prevalence rate of over 10%.
Status of Ban
IDD Cell has been established
in the Directorate of Health Services in 1994. Elimination of IDD was also
included in Chief. Minister's 15 point programme for child welfare.
Iodisation Capacity
Tamil Nadu is the 2nd
largest salt producing state after
Gujarat with an average annual production of about 20-25 lakh tonnes. Salt
Department has permitted 135 salt iodisation units with an annual installed
capacity of 18.24 lakh tonnes which is sufficient to cater to the needs of
14lakh tonnes of all the southern States.
Quality Monitoring at
Production Sources
In order to monitor the
quality of iodised salt at production sources, the Salt Department has
established seven laboratories at Chennai, Tuticorin, Adirampatnam, Vedaranyam,
Veppolodai, Cuddalore and Nagarcoil. Besides, two mobile laboratories have been
deployed at Chennai and Tuticorin to test check the quality of iodised salt on
the spot.
The details of samples
analysed during the last three years are as follows:
|
Year |
Samples analysed |
Found standard |
|
1998 |
12675 |
11726
(92.5) |
|
1999 |
12957 |
11684
(90.0) |
|
2000 |
13943 |
12728
(91.2) |
Salt Department has provided
18 salt iodisation plants with UNICEF
assistance to Small Salt Producers Association and Co-operative Societies. Besides,
Tamil Nadu Salt Corporation has also been provided with iodisation plant for
production and distribution of low priced iodised salt through PDS and FPS.
Monitoring Information System
Food inspector and peripheral
health workers are doing statutory (PFA) and non statutory sampling of iodised
salt at retail and household level to monitor the quality of iodised salt.
Details of samples analysed during the
last 3 years are as follows:
|
|
Samples analysed |
Found
standard |
||
|
PFA |
Non-PFA |
PFA |
Non-PFA |
|
|
1999-2000 (34%) |
1723 |
61800 |
676
(39.2%) |
21205
|
|
2000-2001 (38%) |
772 |
65050 |
277
(36%) |
24767
|
|
2001-2002 (37%) (Upto August) |
262 |
29488 |
120
(46%) |
11076
|
Appendix
XIV
List of principal
investigators along with the districts surveyed
S.No. NAME DISTRICT
1. Dr. G. Krishna Babu Vizag, Vijayanagaram,
Srikakulam
Andhra Medical College
2. Dr. V. Chandrasekhar East Godavari District, West
Godavari District
R.M.C. Kakinada
3. Dr. T.S.R. Manidhar Krishna, Khammam
S.M.C. Vijayawada
4. Dr. K. Vara Prasada Rao Guntur, Prakasam
G.M.C.,
5. Dr.G. Subramanyam Warangal, Adilabad
K.M.C.,
6. Dr. B.V.N. Brahmasewara Rao Hyderabad, Nizambad, Rangareddy
O.M.C., Hyderabad
7. Dr. M. Bhupati Reddy Nalgonda, Karim Nagar, Medak
G.M.C., Hyderabad
8. Dr. C. Niranjan Paul Kurnool, Mehaboob Nagar
K.M.C.,
9. Dr. V.V. Sastry Anantapur, Cuddapah
G.M.C., Anantapur
10. Dr. K. Raghava Prasad Chittoor,
S.V.M.C. Tirupati
Total
No. of PI = 10
Total
No. of Districts = 23
11.
Dr. A.S. Wantamutte Belgaum, Uttara Kannada
J.N.M.C,
12.
Dr. R.S.P. Rao Udupi, Dakshina Kannada,
Chickmagalur
KMC, Manipal
13.
Dr. Bhaya Bagalkot,
Gadag
Alameen Med. College,
Bijapur
14.
Dr. Vijay Ganjoo Bijapur, Raichur
BLDMC, Bijapur
15.
Dr. M.B. Ramamurthy Bangalore (Urban), Davangere, Chitradurga
B.M.C, Bangalore
16.
Dr. T. Gangadhara Goud Bellary, Koppal
V.I.M.S,
17.
Dr. M. Sundar Kolar, Shimoga
SDUMC, Kolar
18.
Dr. Jayanth Kumar Tumkur, Coorg
MSRMC,
19.
Dr. M.B. Rudrapra Dharwad, Haveri
HFWTC, Hubli
20. Dr. Y. Chandrashekhar Hassan, Mysore, Chamaraja Nagar
J.S.S.M.C., Mysore
21.
Dr. D.H. Ashwath Narayana Bangalore
Rural, Mandya
KIMS, Bangalore
22. Dr. S.S. Reshmi Bidar,
MRMC,
Total
No. of PI = 12
Total
No. of Districts = 27
23. Dr. Thomas Bina Kozhikhode, Malappuram
24. Dr. Jeesha. C. Haran Kannur, Kasargod, Wyanad
Medical College
Parijaram, Kannur
25. Dr.
K. Leelamoni Trivandrum, Kollam, Pathanamthitta
Trivandrum Medical College
26. Dr. G. Syamala Kumar Aleppey,
Idukki, Kottayam
Alleppey Medical College
27. Dr. K. Usha Devi Trichur, Palaghat, Ernakulam
Trichur Medical College
Total
No. of PI = 5
Total
No. of Districts = 14
S.No. NAME DISTRICT
28. Dr. M.Danabalan Pondicherry ,
Karaikal, Yanam, Mahe
JIPMER, Pondicherry
Total
No. of PI = 1
Total
No. of Districts = 4
S.No. NAME DISTRICT
29. Dr. Thomas. V. Chakco Nilgiris, Coimbatore, Erode,
Dindigul
30. Dr. Murali Salem,
Namakkal, Kanchepuram
KMC, Chennai
31. Dr. P.Sivaprakasam Dharmapuri, Vellore,
Tiruvallore
Stanley Medical College
32. Dr. Ethiraj Tiruvarur,
Nagapattinam, Cuddalore
33. Dr. RaviVarma Thiruvannamalai,
Villupram, Virudunagar
Madras Medical College
34. Dr. A.T. Ramnath Konyakaman, Tuticorin,
Thesi, Tirunelveli
Madurai Medical College
35. Dr. Jaya Kumar Perambaluor, Trichy,
Karur,
Salem Medical College
36. Dr. P. Rajaram Ramanathapuram,
Pudukkottai, Thanjavur,
Thanjavur Medical College Sivaganga
Total No. of PI =
8
Total
No. of Districts = 28
TOTAL
NUMBER OF PI =
36
TOTAL
NUMBER OF DISTRICTS = 96
Appendix
XV
Detailed addresses of all the
participating centers
I ANDHRA PRADESH
1. Dr. G. Krishnababu, Assistant Professor, Deptt. of Social & Preventive
Medicine, Andhra Medical College, Visakhapatnam, Andhra Pradesh Tel. 549704 ( R); 0891 |
2. Dr. V. Chandrasekhar Prof. & Head, G.G.H Campus, Rangaraya Medical college, Kakinada, Andhra Pradesh Tel: 0884 375831 (Ext. 259) (O) 0884 364837 (R) |
|
3. Dr. K. Varaprasada Rao, Professor, Dept. of Social and Preventive
Medicine, Guntur Medical college, Guntur-522004, Andhra Pradesh. Tel: 0863 221718 (R)
|
4. Dr. G. Subhramanyam Prof and Head Department of Community Medicine Kakatiya Medical College Warangal 506007 AP Tel: 08712-65973 (Extn. 226) (O) 76707 (R ) |
|
5. Dr. C. Niranjan Paul Prof. & Head, Kurnool Medical college, Kurnool, Andhra Pradesh. Tel: 08518 28815, 20160 (Ext. 31) (O) 25343, 78784 (R) |
6. Dr. K. Raghava Prasad, Head, Department of Preventive and Social Medicine, Tirupati Medical College, District Tirupati, Andhra Pradesh. Tel: 08574 27482, 87482 (R) Dr. Venugopal Sharma 30156 ® |
|
7. Dr. T.S.S. Manidhar Prof. & Head, Siddartha Medical College, Vijayawada, Andhra Pradesh
Tel: 0866 541008-9 (O) 0863 240862 (R) |
8. Dr. M. Bhoopati Reddy Prof. & Head, Gandhi Medical college, Hyderabad, Andhra Pradesh Tel:
3260068/3226222 (Ext.731) (O) 4413870 (R) |
|
9. Dr. B.V.N. Brahmeswara Rao Prof. & Head, S.P.M., Osmania Medical college, Hyderabad, Andhra Pradesh. Tel: 040 4656992 (Ext. 119) (O) 040 3730068 (R) |
10.
Dr. V. Visweswara Sastry, Professor, Community Medicine,
Kakitya Medical college, Warangal, Andhra Pradesh. Tel: 08554 20666 (O) 29947 (PP) 08172 |
|
II KARNATAKA 11.Dr.
M. Sundar, Professor, Department of Community Medicine, Sri Devaraj URS Medical College, Tamaka, Kolar-563101, Karnataka. Tel: 22603/22638/24930 (Ext. 115) (O) 5712601 (R) 08152 |
12.Dr.
M. B. Rudrappa, Epidemiologist, Health and
Family Welfare Training Centre, KIMS Campus, Hubli-580022, Karnataka. Tel: 0836 372369/ 372827 (O) 251448 (R) |
|
13.
Dr. Phaneendra Rao, Professor & Head, Department of Community Medicine, Kasturba Medical College, Manipal-576119, Udupi District. Karnataka State. Tel:08252 71201 (Ext.2324/2531) (O) 08252 70588 (R) |
14.
Dr. Reshmi, Professor & Head, Department of Community Medicine, M. R. Medical College, Gulbarga-585105 Karnataka Tel: 20307 (O) 46950 (R) 08472 |
|
15.
Dr. A.S. Wanta Mutte, Professor & Head, Department of Community Medicine, J. N. Medical College, Belagaum. Karnataka State. Tel: 0831 473777(Ext. 1536) (O) 0831 452018 (R) |
16.
Dr. Vijay Ganjoo, Professor & Head, Department of Community Medicine, B.L.D.E. Medical College, Bijapura. Karnataka State. Tel: 08352 50770 (Ext. 2155/2166( (O) 08352 76962 (R); 76747 (R) |
|
17.
Dr. S.S. Yarnal, Professor & Head, Department of Community Medicine, All - Ameen Medical College, Bijapura. Karnataka Tel: 08352- 50186 (R) |
18.
Dr. Ramamurthy, Lecturer, Department of Community Medicine, Bangalore Medical College, Bangalore. Karnataka State. Tel: 6701529 (O) 080 9844081768(M) |
|
19.
Dr. Y. Chandrashekar, Professor & Head, Department of Community Medicine, J. S. S. Medical College, Mysore, Karnataka Tel: 0821 490732 (Ext. 448) (O) 080
5285608 (R) |
20.
Dr. M.V. Sagar, Professor and Head, Vijayanagar Institute of Medical
Sciences, Bellary- 583104. Tel: 42125 ( R)
08392 85046 (R)
Dr. Gangadhar Goud's |
|
III KERALA 21.
Dr. K. Ushadevi, Professor and Head, Department of Community Medicine, Trivananthapuram Medical College, Trivananthapuram-605 011, Kerala. Tel: 0471 528379 (O) 443568 (R) |
22.
Dr. G. Shyamala Kumari, Associate Professor, Department of Community Medicine, T.D. Medical College, Alappuzha, Kerala Tel: 0477 272015 (O) 0481 565875 (R) |
|
23.
Dr. C. Prabhakumari, Associate Professor, Department of Community Medicine, Trissur Medical College, Trissur, Kerala. Tel: 200310 (Ext. 122) (O) 200310 (R) Dr. Asma's |
24.
Dr. Thomas Bina,
Assistant Professor, Department of Community Medicine, Calicut Medical College, Calicut, Kerala Tel: 0495 356531- 298 (O) 740869 (R) |
|
25.
Dr. Jeesha Haran, Professor and Head, Department of Community Medicine, Academy of Medical Sciences, Pariyaram- 670502, Kannur, Kerala Tel: 0497 800363/62/64 (Ext. 174) (O) (Ext. 112) (R) |
IV 26.
Dr. Danabalan, Professor & Head, Department of Community Medicine, Mahatma Gandhi College and
Research Institute, Pillaiyarkuppam, Pondicherry-607402. Tel: 0413 615449-458 (O) 372124 (R) |
|
V TAMIL NADU 27.
Dr. Ethirajan Department of Community Medicine, Raja Muthiah Medical College, Annamalainagar-608002, TAMILNADU Tel: 04144 38068 (O) 38215 (R) |
28.
Dr. A.T. Ramnath. Reader, Institute of Community Medicine, Madurai Medical College, Madurai 625 020. TAMILNADU Tel: 525652 (R) |
29.
Dr. Thomas V. Chacko, Head, Department of Community Medicine, PSG Institute Medical Sciences and Research, Avanashi Road, Peelamedu Coimbatore-641 004. TAMILNADU Tel: 0422 570170 (O) 570247 (R) |
30.
Dr.P. Rajaram, Reader, Dept. of Social and Preventive
Medicine, Thanjavur Medical College, Thanjavur – 613 004. TAMILNADU Tel: 04632 40022 (O) 0435 66533 (R) |
|
31.
Dr. K. Jayakumar, Senior Civil Surgeon, Professor and Head, Department of Social and Preventive Medicine, Govt. Mohan Kumaramangalam Medical College, Salem – 636 003. TAMILNADU Tel: 483313 (O) |
32.
Prof. Murali, Head, Department of Community Medicine, Government Kilpauk Medical College, Chennai 600 010. TAMILNADU Tel: 044 6431926-28 (O) 4983298 (R) |
|
33.
Prof. G. Ravi Varman Associate Professor, Institute of Community Medicine, Madras Medical College Park Town, Chennai- 600 003. TAMILNADU Tel: 5363001 (Ext. 260/261) (O) 4911790 (R) |
34.
Prof. Siva Prakasam, Head, Department of Community Medicine, Stanely Medical College, Chennai 600 001. TAMILNADU Tel: 044 5261345-352 (Ext. 216) (O) 6450650 (R) |
Appendix XVI
Iodometric Titration method
for estimation of iodine in Salt
1.1 Principle
The iodine
content of salt is
estimated by titrametric
procedure known as iodometric titration.
Free iodine reacts with sodium
thiosulphate solution to give a light
yellow colour complex. This
colour complex combines
with soluble chemical starch which indicates the presence of sodium
iodide.
1.2. Equipment and Chemicals
1.2.1 Equipment
i. Laboratory balance
ii. Gas burner or kerosene stove
iii. Reagent bottles with stoppers - 250ml, 500 ml and 1000 ml
iv. Measuring cylinder with stopper - 50 ml
v. Wash bottle - 500ml
vi. Glass stirring rod
vii. Conical flask with stopper - 100ml
viii.
Glass or plastic funnel
ix. Burette - 10 ml
x. Burette stand
xi. Clock or watch
xii. A closed box, cupboard or drawer to keep the
conical flask
1.2.2 Chemicals
i. Sodium thiosulphate, (Na2S2O3 5H2O)
ii. Concentrated sulphuric acid,(H2SO4)
iii. Potassium iodide,(KI)
iv. Soluble chemical starch
All the
chemicals used were analytical
grade and double distilled water
was used which was free of
iodine and other
contaminants.
1.3.
Preparation of reagents
a) Sodium thiosulphate (0.005 M) : 1.24 g sodium thiosulphate was dissolved in 1
litre hot double distilled water. This volume was sufficient for testing 200 salt samples. The solution
was stored in a cool, dark place.
b) Sulphuric acid (2N H2SO4) : 5.56 ml
concentrated sulfuric acid was added dropwise into 90 ml of chilled double
distilled water and the
final volume was made upto 100
ml with double distilled water. This volume was
sufficient for testing 100 salt samples.
CAUTION: To avoid violent and dangerous reaction always
add the acid to water, never add water to acid.
c) Potassium iodide (KI) : 100 g potassium iodide was dissolved
in 1000 ml double distilled water. This volume was sufficient for testing 200
salt samples. This was stored in a refrigerator.
d)
Saturated Salt Solution : 100 ml double distilled water was taken in a conical
flask and sodium chloride was added until the salt was insoluble. This solution was heated till the NaCl
crystals formed on the sides of the
vessels. After cooling down the saturated salt solution
at room temperature the
supernatant was transferred
in a clean bottle.
(e)
Soluble Chemical Starch: 10g
soluble chemical starch was
dissolved in 100 ml hot double distilled water. Then the volume
was adjusted upto 1000 ml with saturated sodium chloride solution. This was
sufficient for testing 200 salt samples.
The starch solution was prepared fresh
every day.
1.4
Procedure
10
g of salt was dissolved in 50 ml double distilled water. Then
1.0 ml of 2 N sulphuric acid and
5.0 ml of 10% potassium iodide was
added. On shaking, the solution
turned a yellow colour. This was incubated at room
temperature in the dark for 10 minutes.
During the incubation
period sodium thiosulphate solution was poured into the burette and the
level of
solution was adjusted to zero. The samples were removed from the
dark and titrated against the sodium
thiosulphate solution until it turned into
a very light yellow colour (pale yellow). Subsequently,
a few drops (1-5ml) of 1% starch
solution was added. The solution turned a deep purple colour. Finally, it was
titrated until the solution became
colourless and the final reading was observed.
1.5.
Result
From table
given below, the iodine content of
the sample in parts per million was calculated
accordingly. The results were recorded in a register, under the following
parameters
- Date of collection
- Date of testing
- Sample number
- Type
of salt
- Cluster number
- The level of iodine in the sample.
1.6 Precautions
(i)
Adding sulphuric acid to a solution of
iodated salt liberates iodine,
which is titrated with
sodium thiosulphate. Potassium
iodide (KI) is used because of the low solubility of iodine and more iodine is dissolved
in order to maintain the equilibrium.
(ii) Potassium iodide solution is added to keep
the iodine in the dissolved state.
(iii)
The reaction mixture should be kept in
the dark for 10 minutes
before titration because
light accelerates a
side reaction in which
iodide ions are
oxidized to iodine
by atmospheric oxygen.
(iv)
Starch solution must be prepared freshly.
(v) Starch is used as an external indicator.
(vi)
The starch solution must be added near the end
of the titration, when
very little amount of iodine is left and
the solution has a faint-yellow colour.
If starch is added earlier, the iodine-starch
complex becomes very strong
and reacts too slowly
with sodium thiosulphate,
resulting in false
high readings.
(vii)
The titration should be done in a comfortably cool room because
iodine is volatile and the sensitivity of the
starch indicator diminishes as the temperature rises.
Table
|
Burette reading |
Parts per million |
Burette reading |
Parts per million |
|
0.0 |
0.0 |
3.0 |
31.7 |
|
0.1 |
1.1 |
3.1 |
32.8 |
|
0.2 |
2.1 |
3.2 |
33.9 |
|
0.3 |
3.2 |
3.3 |
34.9 |
|
0.4 |
4.2 |
3.4 |
36.0 |
|
0.5 |
5.3 |
3.5 |
37.0 |
|
0.6 |
6.3 |
3.6 |
38.1 |
|
0.7 |
7.4 |
3.7 |
39.1 |
|
0.8 |
8.5 |
3.8 |
40.2 |
|
0.9 |
9.5 |
3.9 |
41.3 |
|
1.0 |
10.6 |
4.0 |
42.3 |
|
1.1 |
11.6 |
4.1 |
43.4 |
|
1.2 |
12.7 |
4.2 |
44.4 |
|
1.3 |
13.8 |
4.3 |
45.5 |
|
1.4 |
14.8 |
4.4 |
46.6 |
|
1.5 |
15.9 |
4.5 |
47.6 |
|
1.6 |
16.9 |
4.6 |
48.7 |
|
1.7 |
18.0 |
4.7 |
49.7 |
|
1.8 |
19.0 |
4.8 |
50.8 |
|
1.9 |
20.1 |
4.9 |
51.9 |
|
2.0 |
21.2 |
5.0 |
52.9 |
|
2.1 |
22.2 |
5.1 |
54.0 |
|
2.2 |
23.3 |
5.2 |
55.0 |
|
2.3 |
24.3 |
5.3 |
56.1 |
|
2.4 |
25.4 |
5.4 |
57.1 |
|
2.5 |
26.5 |
5.5 |
58.2 |
|
2.6 |
27.5 |
5.6 |
59.2 |
|
2.7 |
28.6 |
5.7 |
60.3 |
|
2.8 |
29.6 |
5.8 |
61.4 |
|
2.9 |
30.7 |
5.9 |
62.4 |
Table
|
Burette reading |
Parts per million |
Burette reading |
Parts per million |
|
6.0 |
63.5 |
8.0 |
84.6 |
|
6.1 |
64.5 |
8.1 |
85.7 |
|
6.2 |
65.6 |
8.2 |
86.8 |
|
6.3 |
66.7 |
8.3 |
87.8 |
|
6.4 |
67.7 |
8.4 |
88.9 |
|
6.5 |
68.8 |
8.5 |
89.9 |
|
6.6 |
69.8 |
8.6 |
91.0 |
|
6.7 |
70.9 |
8.7 |
92.0 |
|
6.8 |
71.9 |
8.8 |
93.1 |
|
6.9 |
73.0 |
8.9 |
94.2 |
|
7.0 |
74.1 |
9.0 |
95.2 |
|
7.1 |
75.1 |
9.1 |
96.3 |
|
7.2 |
76.2 |
9.2 |
97.3 |
|
7.3 |
77.2 |
9.3 |
98.4 |
|
7.4 |
78.3 |
9.4 |
99.5 |
|
7.5 |
79.4 |
9.5 |
100.5 |
|
7.6 |
80.4 |
9.6 |
101.6 |
|
7.7 |
81.5 |
9.7 |
102.6 |
|
7.8 |
82.5 |
9.8 |
103.7 |
|
7.9 |
83.6 |
9.9 |
104.7 |
Method for Internal Quality Control adopted
A known positive iodized salt sample was obtained and
by performing multiple analyses on this positive salt sample, a concentration range was
established and used for internal quality control purposes.
Once a
sufficient number of these test results
were obtained, the samples mean concentration (X)
in ppm and standard deviation
(SD) was also calculated. The 95% confidence interval was then calculated and
used as the operating control range, as follows:
Sample Mean (X)
± 2(SD)
The X - 2(SD) = the lower confidence limit (L)
X + 2(SD) = the upper
confidence limit (U)
The operating
control range is between L and U.
This internal quality control sample was run with every
batch of the test samples and the internal quality control was successful when
the results of this sample were between the lower and upper
limits (i.e., the
L-U range), for 95% of test
results. If the results were outside the established range they were
considered potentially suspicious and the whole batch was repeated.
The quality control chart was prepared to ensure the
validity of the results obtained. A
regular linear graph paper was used to prepare these plots. The mean
salt iodine concentration (in ppm) of the internal quality control sample was plotted as a continuous horizontal
line on the Y-axis. The lower
concentration value (L) was plotted below the mean line on the Y-axis scale and the upper concentration value (U)
was plotted above the mean line on the
Y-axis scale. The X-axis was used to
plot the date on which the internal quality control sample was analysed.
This chart was used to plot
the specific analysis date,
and salt iodine concentration obtained
for the control every time it was tested. If the value of the
internal quality control sample was
between the two limit lines, then the test
was deemed in control,
and all results were accepted.
Any internal quality control value that was plotted outside the two
limit lines then the test was considered as out-of-control, and the entire
batch was repeated.
+ 2SD(U)
Mean (X)
- 2SD(L)
Date 16 17 20 22
Appendix XVII
Wet digestion method for
estimation of iodine in urine
1.1. Principle
Urine is
digested with chloric acid under
mild conditions and iodine is determined manually by its
catalytic role in the reduction of ceric ammonium sulfate in
the presence of arsenious acid. As the
reduction proceeds the intensity of colour decreases and this can be readily measured in a
spectrophotometer at 420 nm. The method is fast and inexpensive,
and the digestion is less harsh than
some other methods. This method can
measure urinary iodine concentrations in
the range of 0-150 mcg/liter but can be
extended further to cover a wider range of values.
1.2. Equipment and Chemicals
1.2.1. Equipment
Oven with fan
exhaust, vented fume
hood on oven
for perchloric acid escape, UV spectrophotometer, thermometer, Timer (stop
watch reliable to 5 second, test tubes (15mm x 100mm),
funnel (56x100 mm) reagent flasks and
bottles, pipettes Whatman no 1 filter
paper and a laboratory balance.
1.2.2. Chemicals (analytical grade AR /GR)
i) KCLO3
(potassium chlorate),
ii) HCLO4
(perchloric acid, 70%)
iii) As2O3
(arsenic trioxide),
iv) NaOH
(sodium hydroxide),
v) H2SO4
(sulfuric acid)
vi) Ce(NH4)4
(SO4)4 2H2O (ceric ammonium sulfate),
vii) KIO3
(potassium iodate),
viii) HCL
(Hydrochloric Acid)
ix) Double distilled
water (free of
iodine and other contaminants)
1.3. Preparation of reagents
i) Chloric acid
solution
In a 2000ml
Erlenmeyer flask, 500g potassium
chlorate was dissolved in 910ml hot double distilled water until
the soluble state (normally a little amount remains
undissolved). 375 ml of 70% perchloric
acid was added dropwise (approx. 15 ml/min)
while stirring constantly. This preparation was carried out in a vented
fume hood as it produces toxic fumes. Subsequently, the solution was
kept in a freezer
of refrigerator overnight for
better separation. The next day
it was filtered through a filter paper, (Whatman # 1) and stored in a
refrigerator at 40C.
ii) Arsenious Acid Solution
0.986 g arsenic
trioxide was taken in a 1000 ml
volumetric flask and was
dissolved in 10 ml of 0.5 N hot sodium
hydroxide.
This
solution was transferred
into 750 ml
chilled double distilled water. Then 20 ml concentrated HCL and 39.6 ml
conc. sulphuric acid (98%) was added dropwise with constant mixing. The
solution was stored in amber colour
bottle at room temperature.
(The solution is stable for months).
iii) Sulphuric Acid Solution (3.5N H2SO4)
97 ml
concentrated sulfuric acid (98%) was
added dropwise into 800 ml
chilled double distilled water (carefully
as this generates heat) and
final volume was made up to 1
litre with double distilled water.
iv) Ceric
ammonium sulfate solution
48g ceric
ammonium sulfate was dissolved in 1 litre of 3.5N H2SO4. This
was stored in a amber
colour bottle at
room temperature. (The solution is stable for months).
i.Stock Iodine Standard
(1mg/ml)
168.5 mg KIO3 was dissolved in double distilled water to make a
final volume of 100 ml. This was stored
in a amber colour bottled (This solution is stable for months).
vi) Dilute Iodine Standard (1ug/ml) : Take 100 ul
of Stock Iodine Standard and make
a volume to 100 ml with double distilled water.
ii.Working Iodine
Standard
Make the following
serial dilutions from diluted
Iodine Standard (1ug/ml) into volumetric
flasks (10 ml)
with double distilled water (diluent).
These dilutions are made freshly.
ug/dl Dilution fators
5 ug :
0.5 ml of 1 ug/ml standard + 9.5 ml diluent
10 ug
: 1.0 ml of 1 ug/ml standard +
9.0 ml diluent
15 ug
: 1.5 ml of 1 ug/ml standard +
8.5 ml diluent
20 ug
: 2.0 ml of 1 ug/ml standard +
8.0 ml diluent
1.4. PROCEDURE
Step I.: The
urine sample was shaken to
evenly suspend any sediment.
250 ul of each urine sample was pipetted into a
15x100 mm test tube. Iodine standards were prepared from
the 1 ug/ml stock iodine solution. The iodine
standards corresponding to 0/5/10/15 and 20 ug/dl
were prepared.
Step II : 750 micro liter of chloric acid solution was
added to each tube
(samples, blank, internal quality
control sample, standards) and
mixed gently. All tubes were placed in the oven at 1100C-1200C for 75 minutes (with a
fume hood for the trapping of perchloric
acid). There will be very little volume change during heating. some samples may be
faintly yellow. All the tubes were
cooled at room
temperature for 15 minutes.
Then, the decreased volume
was adjusted with double
distilled water to their original volume (1.0 ml) and
vortexed.
Step III : 3.5 ml of Arsenious Acid was added to each test
tube and after mixing all test
tubes were kept for 15 minutes at room
temperature.
Step IV : 350
microliter of ceric ammonium sulfate solution
was added at a fixed interval of time to each tube and quickly mixed with
help of a vortex. A stopwatch was used to keep a
constant interval between additions to successive tubes, (30 seconds was
a convenient interval). Exactly 20 minutes after addition of ceric ammonium sulfate
to the first tube, the
reduction was read spectrophotometrically at 420 nm against
the reagent blank at the same interval. (Successive tubes were arranged in a
such a manner that the interval between the time of addition of ceric ammonium sulfate and the time of the reading was the
exactly 20 minutes for all samples, standards and
blanks).
1.5.
Calculation of results
The exact value of urine sample's iodine was calculated as follows:
1. The average absorbance value for each set of
reference standard, control and samples was calculated.
2. A standard curve was constructed by plotting
the mean absorbance obtained for each reference standard against its
concentration in µg/l on linear graph
paper, with absorbance on the
vertical (Y) axis and
concentration (µg/l) on the horizontal (X) axis.
1.6. PRECAUTIONS
1. Since
the digestion procedure has no specific end point, it is essential to run
blanks and IODINE standards with each assay to allow for variations in
heating time, etc.
2. The exact temperature, heating time
and cooling time can vary. However,
within each assay, the interval between the time of addition of ceric ammonium
sulfate and the time of the reading must
be the same for all samples, standards, and blanks.
3. In this procedure it is convenient to run 60
sample's tubes per assay of which 5 are
standards (at concentrations of
0/5/10/15and 20 mcg/dl).
4. Perchloric acid fumes can be toxic and the
complex generated may be harmful, particularly if allowed to dry in a
ventilation system. The recommended
method releases much less perchloric acid than other digestion methods.
5. The
exact time and temperature is not critical as long as all tubes are heated the same way.
6. 1.68mg KIO3 contains 1 mg iodine KIO3 is
preferred over KI because it is more stable.
7. Test
tubes can be reused if they are carefully washed to eliminate any iodine contamination.
8. Separate
pipettes should be used for all the test
tubes and also pipettes used for
preperation of each standard solution should be kept separately and not be mixed
with the general pool of glasswares. They
should be kept separately for all times to avoid
contamination.
Method
for Internal Quality Control adopted
A pooled urine sample was
prepared for internal quality control assessment. The internal quality control
sample was analysed 20-25 times with
standards and blank in duplicate. The mean (X) and standard deviation (SD) of this internal
quality control sample was calculated and the sample was stored in refrigerator
and analysed with every batch of samples. The 95% confidence interval was then calculated and used as the
operating control range, as follows:
Sample Mean (X)
± 2(SD)
The X - 2(SD) = the lower confidence limit (L)
X + 2(SD) = the upper
confidence limit (U)
The operating
control range is between L and U.
A regular linear graph paper was used to prepare these
plots. The mean urinary iodine concentration (in ppm) of the internal quality
control sample was plotted as a continuous horizontal line on the Y-axis. The lower concentration value (L)
was plotted below the mean line on the Y-axis
scale and the upper concentration value (U) was plotted above the mean line on the Y-axis scale. The X-axis was used to plot the date
on which the internal quality control sample was analysed. This chart was used to plot
the specific analysis date,
and urinary iodine concentration obtained for
the internal quality control sample every time it was tested. If the value of the internal quality control
sample was between the two limit lines, then the test was deemed
in control, and all results were
accepted. Any value of the internal
quality control sample that was plotted outside the two limit lines then, the
test was considered as out-of-control, and the entire batch was repeated.
LEVY
JENNING PLOT
+ 2SD(U)
Mean (X)
- 2SD(L)
Date 16 17 20 22
Prepared by a technical
group consisting of
Dr.Umesh Kapil, M.D.
Ms.Preeti Singh, M.Sc.
Ms.Priyali Pathak, M.Sc.