TBS/CDC -7 (2901 ) P3 
 
 
©TBS 2017 – All rights reserved      Second edition 2017  
  0  
DRAFT TANZANIA STANDARD  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
TBS/CDC -7(2901 ) P3- Sodium hydroxide  - Specification   
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
TANZANIA BUREAU OF STANDARDS  
 
  
 
 
    
  TBS/CDC -7 (2901 ) P3 
 
 
©TBS 2017 – All rights reserved      Second edition 2017  
  1  
 
 
 
Foreword  
 
This Draft Tanzania Standard is being  developed by the Industrial and Laboratory Chemicals 
Technical Committee under supervision of the Chemical s Division Standards Committee and it 
is in accordance with the procedures of the Bureau.  
 
This second edition after being finalized will cancel and thus replace the first edition (TZS 378: 
1989  Specification for Sodium hydroxide (pure, technical and analytical ). 
 
This draft Tanzania Standard has been prepared with assistance drawn from:  
IS 252: 201 3 – Caustic soda –Specification ,  
IS 4016: 2002 Density composition tables for aqueous solutions of sodium hydroxide , all 
published by Bureau of Indian Standards Institution,   
BS 4130: 2011  – Specification for sodium hydroxide (technical grades) published by Bureau of 
British Standards Institution.  
 
In reporting the test results of a test or analysis made in accordance with this standard, if final 
value, calculated or observed is to be rounded off, it shall be done in accordance with TZS 4: 
Rounding off numerical values . 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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©TBS 2017 – All rights reserved      Second edition 2017  
  2 DRAFT TANZANIA STANDARD                                   TBS/CDC7 ( 2901 ) P3 
 
Sodium hydroxide - Specification   
 
1. Scope  
 
1.1. This draft Tanzania Standard specifies requirements , sampling and methods of tests  for 
sodium hydroxide  suitable for use in rayon, cosmetic, textile, soap, paper and other similar 
industries.  
 
1.2 The specification does not apply to sodium hydroxide used for pharmaceutical , 
photographical  or food processing  purposes.  
 
2. Normative references  
The following referenced documents are indispensable for the application of this document. 
The latest edition of the referenced document (including any amendments) applies;  
 
TZS 379  Code of safet y for handling sodium hydroxide  
TZS 494  Determination of carbonate content of sodium hydroxide ( NaOH ) 
TZS 382  Method of assay of sodium hydroxide NaOH  
TZS 495  Determination of chloride content of sodium hydroxide ( NaOH ) 
TZS 496  Determination of sulphate content of sodium hydroxide ( NaOH ) 
TZS 497 Determination of silica content of sodium hydroxide ( NaOH ) 
TZS 381  Determination of Iron content of sodium hydroxide ( NaOH ) 
TZS 383  Determination of Copper content of sodium hydroxide ( NaOH ) 
TZS 384  Determination of Calcium and Magnesium content of sodium  hydroxide ( NaOH ) 
TZS 385  Determination of matter insoluble in water of sodium hydroxide ( NaOH ) 
TZS 386  Sampling  of pure, technical and analytical sodium hydroxide ( NaOH ) 
TZS 498/ ISO 5993  Sodium hydroxide for industrial use – Determination of mercury content - 
Flameless atomic absorption spectrometric method   
TZS 505 Specification for Hydrochloric acid  
TZS 74 Specification for Sulphuric acid  
 
3. Grades  
There shall be three grades of the sodium hydroxide namely; pure, technical and analytical.  
 
4. Requirements  
 
4.1 General requirements  
 
4.1.1  Sodium hydroxide shall be supplied in the form of lye or solid including flakes, blocks, 
sticks and pellets.  
 
4.1.2  Sodium hydroxide shall be free from foreign matter, dirty or other visible impurities.  
 
4.2 Specific requirement s  
Sodium hydroxide shall also comply with t he requirements given in the T able 1 below   
 
 
 
 
 
 
 
 
 
 
 
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©TBS 2017 – All rights reserved      Second edition 2017  
  3 Table 1: Requirements for Sodium hydroxide   
 
S/No:  Parameter  Requirements  
Method of 
test  Pure  Technical  Analytical  
i.  Sodium hydroxide (as NaOH), 
percent by mass, min  99.50  95.00  98.0 TZS 382  
ii.  Sodium carbonate (as Na 2CO 3), 
percent by mass, max  0.40 2.00 1.0 TZS 494  
iii.  Chlorides (as Cl), percent by 
mass, max  0.10 3.50 0.005  TZS 495  
iv.  Sulphates ( as SO 4), percent by 
mass, max  0.10 3.50 0.005  TZS 496  
v.  Nitrates (as NO 3), percent by 
mass, max  N/A N/A 0.0005  Annex B  
vi.  Phosphates ( as PO 4), percent 
by mass, max  N/A N/A 0.001  Annex C  
vii.  Silicates (as SiO 2), percent by 
mass, max  0.02 N/A 0.01 TZS 497  
viii.  Lead (Pb), percent by mass, 
max N/A N/A 0.01 Annex J  
ix.  Iron (as Fe), percent by mass, 
max 0.002  0.035  0.001  TZS 381  
x.  Aluminium (as Al), percent by 
mass, max  N/A N/A 0.002  Annex D  
xi.  Zinc (as Zn), percent by mass, 
max N/A N/A 0.001  Annex E  
xii.  Ammonia (as NH 4), percent by 
mass, max  N/A N/A 0.0005  Annex F  
xiii.  Calcium (as Ca), percent by 
mass, max  N/A N/A 0.004  TZS 384  
xiv.  Arsenic (as As), percent by 
mass, max  N/A N/A 0.00005   Annex K  
xv.  Insoluble matter, percent by 
mass, max  N/A 0.2 0.01 TZS 385  
xvi.  Nickel (as Ni), percent by mass, 
max N/A N/A 0.001  Annex G  
xvii.  Potassium (as K), percent by 
mass, max  N/A N/A 0.02 Annex H  
xviii.  Copper (as Cu), percent by 
mass, max  2.0 N/A N/A TZS 383  
xix.  Manganese (as Mn), percent by 
mass, max  1.0 N/A N/A Annex I  
xx.  Total mercury (as Hg), ppm, 
max 0.01 0.01 0.01 TZS498/ ISO 
5993  
 
Note:  
 
N/A = “Not applicable;  stands for  parameters  which are  not tested for particular grade   
 
5. Sampling  
Representative samples of Sodium hydroxide shall be drawn as prescribed in TZS 386 .  
 
6. Precautions in handling and storing  
The precautions in handling and storing as given in TZS 379 shall be observed.  
 
7. Packing and Marking  
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©TBS 2017 – All rights reserved      Second edition 2017  
  4 8.1 Packing  
The material shall be supplied in sound, clean and dry containers or as agreed between the 
purchaser and the supplier  provided that the minimum requirement is met . The container shall 
be capable of being resealed so as to avoid absorption of carbon dioxide and moisture from 
the atmosphere.   
 
8.2 Marking   
Each container shall be securely closed , and shall bear legibly a nd indelibly the following 
information:  
 
a) Name,  grade , chemical composition  and form of the material  
b) name of the manufacturer and recogn ized trade mark, if any  
c) net mass of the material  
d) lot or bat ch number, in code or otherwise   
e) year of manufacture   
f) safety precautions such as ‘Corrosive – Handle with care’ . 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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©TBS 2017 – All rights reserved      Second edition 2017  
  5 Annex A  
(Normative)  
 
Preparation of Sample Solution  
 
A.1 General — Special care shall be taken in sampling to obtain a  representative sample and 
to avoid absorption of water and carbon  dioxide by the sample taken.  
 
A.2 Procedure — Weigh quickly about 50 g of the material correctly  up to two decimal  places 
in a stoppered weighing bottle and dissolve in cooled distilled water Cool  and dil ute the solution 
to 500 mL in a volumetric flask. Store in a dry bottle fitted with a rubber stopper.  Use this sample 
solution for tests, where specified.   
 
A.3 This solution, if not used on t he same day, shall be protected from access to carbon dioxide 
and moistu re.  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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©TBS 2017 – All rights reserved      Second edition 2017  
  6 Annex  B 
(Normative)  
 
Test for Nitrates  
B.1 Reagents  
B.1.1 Dilute Sulphuric Acid — approximately 5 N,  
B.1.2 Concentrated Hydrochloric Acid — see TZS 505:  
B.1.3 Standard Potassium Nitrate Solution — 0.001 N,  
B.1.4 Concentrated Sulphuric Acid — see TZS 74:  
B.1.5 Standard Indigo Carmine Solution — Dissolve 0.2 mg of indigo  carmine in 400 mL of 
dilute sulphuric acid and add 20 mL of concentrated  hydrochloric acid and suff icient dilute 
sulphuric acid to make up  the vol ume to 1 000 mL. Dilute 1 00 mL of the solution to 1  000 mL. 
Standardize the solution so that 100 mL added to 3.3 mL of potassium  nitrate solution is just 
decolourized on adding 13 mL of concentrated  sulphuric acid and heating to boiling. One 
millilitre of this solution is  equivale nt to 0.002 mg of nitrate ( as NO 3). 
B.1.6 Dilute Ammonium Hydroxide Solution — approximately 5 N  
 
B.2 Procedure  
Transfer 50 mL of the sample solution ( A.2) into  a 250 mL volume tric flask, add 50 mL of dilute 
ammonium hydroxide  solution, make up to the mark and filter by suction. To 20 mL of the  filtrate 
add 5 mL of dilute sulphuric acid, 1 mL of standard indigo  carmine sol ution and 20 mL of 
concentrated sulphuric acid and heat to  boiling.  
 
B.3 The limit prescribed for nitrates shall be taken as not having been  exceeded if the blue 
colour does not entirely disappear.  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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©TBS 2017 – All rights reserved      Second edition 2017  
  7 Annex C 
(Normative)  
 
Test for Phosphates  
C.1 Apparatus  
Nessler Cylinders — 50 mL capacity  
More apparatus to be included  
 
 
C.2 Reagents  
C.2.1 Dilute Sulphuric Acid — approximately 5 N  
C.2.2 Phosphate Reagent No. 1 — Dissolve 5 g of ammonium molybdate  in 100 mL of 1 N 
sulphuric acid.  
C.2.3 Phosphate Reagent No. 2 — Dissolve 0.2 g of methyl -p-aminophenol  sulphate ( metol ) 
and 20 g of potassium meta - bisulphite  in 100 mL of water.  
C.2.4 Standard Phosphate Solution — Dissolve 1.43 g of potassium  dihydrogen phosphate in 
water and dilute to 1 000 mL. Store in a  polyethylene bottle. Dilute 10 mL of this solution to 1 
000 mL in a measuring flask immediately before use. 1 mL of the diluted  solution contains 0.01 
mg of phosphate ( as PO 4). 
 
C.3 Preparation of Sample Solution — Dissolve approximately 2 g  of material correctly up to 
two decimal  places  in 20 mL of water in  a platinum dish, neutralize with about 10 mL of dilute 
sulphuric acid;  add 2 mL of the acid in excess and dilute to 50 mL. Use this solution  for tests in 
C.4 
 
C.4 Procedure  
Transfer 25 mL of the sample solution ( C.3) into a Nessler cylinder. Add 2  mL of dilute sulphuric 
acid, 1 mL of phosphate reagent No. 1 and 1 mL of phosphate reagent No. 2 and dilute  to 50 
mL with water. Carry out a control test in the other Nessler  cylinder using 1 mL of standard 
phosphate solution in place of the  material and the  same quantities of other reagents in the 
same total  volume of the reaction  mixture. Keep both the cylinders in a water  bath at 60°C for 
10 minu tes and then compare the colour produced in  both the cylinders after 5 minutes.  
 
C.5 The limit prescribed for ph osphates shall be taken as not having  been exceeded if any blue 
colour developed in the test with the material  is not deeper than that produced in the control 
test. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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©TBS 2017 – All rights reserved      Second edition 2017  
  8 Annex D  
(Normative)  
 
Test for Aluminium  
D.1 Apparatus  
D.1.1 Nessler Cylinders — 50 mL capacity  
 
D.1.2 Reagents  
D.1.2.1 Dilute Acetic Acid — Dissolve 28.5 g of glacial acetic acid in  100 mL of water.  
D.1.2.2 Ammonium Aurine Tricarboxylate  Aluminon Solution — Dissolve  0.1 g of ammonium 
aurine tricarboxylate in 100 mL of water.  
D.1.2.3 Ammonium Carbonate Solution — approximately 5 N  
D.1.2.4 Standard Aluminium Solution — Dissolve 1.680 g of aluminium  ammonium sulphate 
[AlNH 4(SO 4)2.12H 2O] and dilute to 1 000 mL. Further dilute 10 mL of this solution to 100 mL. 1 
mL of the diluted solution contains 0.01 mg of aluminium (as Al ). 
 
 
D.3 Procedure  
Transfer 10 mL of the sample solution ( A.2) into a Nessler cylinder. Add 10 mL of dilute acetic 
acid and 1 mL of ammonium aurine tricarboxylate solution. Allow to stand for 5 minutes  and 
then add 10 mL of ammonium carbonate solution. Carry out a  control test in the other Nessler 
cylinder using 2.0 mL of standard aluminium  solution, 15 mL of water, 1 g of ammonium acetate, 
5 mL of dilute acetic acid and 1 mL of ammonium aurine t ricarboxylate solution  and adding, 
after a lapse of 5 minutes, 20 mL of ammonium carbonate  solution. Make up the volume in the 
two cylinders to 50 mL and compare the colour produced in the two cylinders after 5 minutes.  
 
D.4 The limit prescribed for aluminium shall be taken as not having  been exceeded, if any pink 
colour produced in the test with the material  is not deeper than that produced in the control test.  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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©TBS 2017 – All rights reserved      Second edition 2017  
  9 Annex E  
(Normative)  
 
Test for Zinc  
E.1 Apparatus  
 Nessler Cylinders — 50 mL capacity  
 
E.2 Method A  
E.2.1 Reagents  
E.2.1.1 Dilute sulphuric acid — approximately 5 N, zinc -free. 
E.2.1.2 Ammonium thiocyanate solution — Dissolve 57 g of  ammoni um thiocyanate ( zinc-free) 
in 100 mL of water.  
E.2.1.3 p-Dimethyl -amine styryl B -naphthaiozole methiodide solution — approximately 0.05 
percent (m/v) in rectified spirit  
 
E.2.2 Procedure  
Transfer, by means of a pipette, exactly 20 mL of the sample solution ( A.2), into a Nessler 
cylinder and neutralize with  dilute sulphuric acid ( about 10 mL), adding one drop in excess. 
Then add  one drop of ammonium thiocyanate solution and 0.1 mL of ρ-dimethyl -aminostyryl  b-
naphthaiozole  methiodide solution. Carry out a blank in  another Nessler cylinder using 30 mL 
of water, one drop of dilute sulphuric  acid, one drop of ammonium thiocyanate solution and 0.1 
mL of ρ-dimethyl -aminostyryl b-naphthaiozole methiodide solution. Make  up the volume in the 
two cylinders to 50 mL and compare the colour  produced immediately.  
 
E.2.3 The limit prescribed for zinc shall be taken as not having  been exceeded, if the colour 
produced immediately in the test with the  material is not pink when compared with that 
produced in the blank  test. 
 
E.3 Method B — this method shall be used when  the reagents  required for Method A are not 
available.  
 
E.3.1 Reagents  
E.3.1.1 Dilute sulphuric acid — approximately 5 N.  
E.3.1.2 Dilute hydrochloric acid — approximately 5 N.  
E.3.1.3 Potassium ferrocyanide solution — Dissolve about 4.2 g of  potassium ferrocyanide in 
100 mL of water.  
 
E.3.2 Procedure  
Transfer, by means of a pipette, 10 mL of the  sample solution ( A.2), into a Nessler cylinder and 
neutralize with  dilute sulphuric acid (about 2.5 mL) adding one drop in excess. Dilute  with water 
to 30 mL. Add 1 mL of dilute hydrochloric acid and 1 mL of potassium fer rocyanide solution. 
Make up the volume to 50 mL. Carry  out a blank in the other Nessler cylinder using the same 
quantities of  reagents in the same total volume of the reacti on mixture. Allow both  the solutions 
to stand for 1 hour and compare the opalescence produced.  
 
E.3.3 The limit prescribed for zinc shall be taken as not having  been exceeding , if the 
opalescence produced in the test with the material  is not greater than that produced in the blank 
test. 
 
 
 
 
 
 
 
 
 
 
 
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©TBS 2017 – All rights reserved      Second edition 2017  
  10 Annex F  
(Normative)  
 
Test for Ammonia  
F.1 Apparatus  
Nessler Cylinders — 50 mL capacity  
 
F.2 Reagents  
F.2.1 Potassium Iodide — crystals, iodate -free. 
F.2.2 Mercuric Chloride Solution — saturated.  
F.2.3 Potassium Hydroxide — solid 
F.2.4 Nessler's Solution — Dissolve 10 g of potassium iodide in  10 mL of ammonia -free water, 
and add to it slowly, with stirring mercuric chloride solution until a slight permanent p recipitate 
forms. Add 30  g of potassium hydrox ide, and when it has dissolved, add 1 mL more of the 
mercuric chloride sol ution and dilute to 200 mL with ammonia -free water. Allow to set tle 
overnight, decant the clear solution and keep it in a bottle closed w ith a well -fitting rubber 
stopper.  
F.2.5 Standard Ammonium Chloride Solution — Dissolve 0.296 g of  ammonium chloride in 
ammonia -free water and make up the volume to 100 mL. Dilute 10 mL of this solutio n to 1  000 
mL with ammonia -free water. 1 mL of the diluted solution contains 0.01 mg of  ammonium  (as 
NH 4). 
 
F.3 Procedure  
Transfer, by means of a pipette, 20 mL of the  sample solution ( A.2) into a Nessler  cylinder and 
dilute with 30 mL of water. Then add 2 mL of Nessler's solution. Make up the volume to 50 mL. 
Carry out a control test in the ot her Nessler cylinder using 1 mL of standard ammonium chloride 
solution and 2 mL of Nessler's solutio n in the same total volume of the reaction mix ture. 
Compare the colour produced in the two cylinders after 5 minutes.  
 
F.4 The limit prescribed for ammonia shall be taken as not having  been exceeded, if any colour 
prescribed i n the test with the material is not deeper than that produced in the control test.  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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©TBS 2017 – All rights reserved      Second edition 2017  
  11 Annex G 
(Normative)  
 
Test for Nickel  
G.1 Apparatus  
Nessler Cylinders — 50 mL capacity  
 
G.2 Reagents  
G.2.1 Citric Acid  
G.2.2 Dilute Ammonia Solution — relative density 0.90  
G.2.3 Dimethyl Glyoxime — 1 percent ( m/v) solution in alcohol  
G.2.4 Standard Nickel Solution — Dissolve 4.05 g of nickel chloride  (NiCl 2.6H 2O) in 50 mL of 
hydrochlori c acid and dilute with water to make up the volume to 1 litre. Dilute 10 mL of this 
solution to 1 000 mL. One millilitre of this solution is equivalent to  0.01 mg of nickel (as Ni ). 
 
G.3 Procedure — Transfer 10 mL of the sample solution ( A.2) in a Nessler cylinder and dilute 
with wa ter to 15 mL. Add 2 g of citric acid and dilute with ammonia solution ti ll the contents 
become slightly alkaline to litmus paper. Add 1 mL of dimethyl glyoxime and make up the 
volume to 50 mL with water. Carry ou t a co ntrol test, using 1 mL of standard nickel solution and 
the same quan tities of other reagents in the same total volume of the reaction mixture. Compare 
the co lour produced after 5 minutes.  
 
G.4 The limit prescribed for nickel shall be taken as not having  been exceeded, if any pink 
colour produce d in the test with the material is not deeper than that produced in the control test.  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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©TBS 2017 – All rights reserved      Second edition 2017  
  12 Annex H  
(Normative)  
 
Test for Potassium  
H.1 Apparatus  
Flame Photometer  — Equipped with interference filter; atomizer  and burner; optical selective 
device consistin g of the reflectors, lenses and diaphragms; and measuring instrument 
consisting of photocell, amplifier and sensitive galvanometer. The gal vanometer scale, which 
measures the inten sity of the radiation transmit ted by the element, shall range from 0 to 100.  
 
H.2 Reagent  
H.2.1 Standard Potassium Solution — Weigh exactly 1 g of potassium  chloride, dissolve in 
water and dilute to  1 000 mL in a measuring flask. Further dilute 100 mL of this solution to  1 
000 mL. The diluted solution contains 0.01 g of potassium chloride per 100 mL. 
 
H.3 Preparation of Sample Solution — Dissolve approximately  10 g of the sample, dried and 
accurate ly weighed, in minimum quantity of water and dilute to 100 mL in a measuring flask.  
 
H.4 Calibration Graph — Take 10, 20, 40, 60 and 80 mL of standard potassium solution ( H.2.1) 
and dilute to 100 mL in different measuring flasks. The flasks now con tain 0.01, 0.02, 0.04, 0.06 
and 0.08 g  of corresponding — galvanometer readings as given in H.5 and plot, the 
concentrations against galvano meter readings in a rectangular co-ordinate graph. Draw a 
smooth curve over the points which give a calibration graph in the range 0.01 % to 0.1 % 
potassium chloride.  
 
H.5 Procedure  
H.5.1 Insert the potassium filter corresponding to wave -length  767 mm, light the burner fed by 
illuminating gas (laboratory gas), adjust the specified air pressure between 0.5 to 0.6 kg/cm2 , 
and maintain the above air pressure constant such that f lame is non -luminous by turning the 
control knob.  
 
H.5.2 Spray — Water and adjust the pointer to zero in  galvanometer scale by zero adjus tment 
knob, then spray the standard potassium chloride solution and adj ust the deflection to maximu m 
(100) by using sensitivity control knob. Again,  spray water to see whether  the pointer comes to 
zero, and standard s olution to indicate 100. Repeat till water reads zero and standard solution 
reads 100 with same adjustment  during both the operations.  
 
H.5.3 Without altering the earlier adjustment of the instrument,  spray various, diluted solutions 
prepared in H.4 and obtain calibration graph in the range 0.01 to 0.1 pe rcent potassium 
chloride. After washing with water, spray the sample solut ion and obtai n the galvanometer 
readings. From the graph, read out the corresponding concentration of potassium chloride in 
the solution ( A). 
 
H.6 Calculation  
 
Potassium, percent by mass =  
 
Where , 
A = concentration of p otassium chloride in the sample solution, and  
M = mass in g of the dried sample taken for the test.  
 
 
 
 
 
 
 
 
 
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©TBS 2017 – All rights reserved      Second edition 2017  
  13 Annex I  
(Normative)  
 
Test for manganese  
 
I.1 Apparatus — Nessler cylinder, 100 -mL capacity  
 
I.2 Reagents  
I.2.1 Phosphoric Acid — 85 percent (manganese free).  
I.2.2 Potassium Periodate  
I.2.3 Standard Manganese Solution —Dissolve 0.307 7 g of manganese sulphate, monohydrate  
(MnSO 4.H2O) in water, add 1 mL of concentrated  sulphuric acid and make up the volume  to 1 
000-mL in a volumetric flask. Pipette out  10 mL of this solution in a 100 -mL volumetric  flask and 
dilute to the mark. One mL of this solution is equivalent to 0.01 mg of manganese.  
 
I.3 Procedure  
I.3.1 Weigh about 10 g of the material to the nearest 0.1 g and transfer it to a 400-mL beaker 
and dissolve in about 40 mL water; to this solution, add 10 to 15 mL of phosphoric acid and 0.6 
to 0.8 g potassium periodate. Heat the solution to boiling. Boil for 20 minutes. Cool the solution 
to room temperature. Transfer the solution to a 100 mL Nessler cylinder. Make up to the mark 
with distilled water and mix well. Compare the colour with that in the other Nessler cylinder 
containing 1 mL of standard manganese solution in place of the test solution treated similarly 
under similar conditions with the same amounts of reagents for  the same time as in the test 
solution, and make up to 100 mL mark.  
 
I.3.2 The limit prescribed shall be taken as not having exceeded if the intensity of colour 
produced in the test with the material is not greater than that in the control test.  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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©TBS 2017 – All rights reserved      Second edition 2017  
  14 Annex J  
(Normative)  
 
Test for Lead  
J.1 Apparatus  
Nessler Cylinders — 50 mL capacity  
 
J.2 Reagents  
J.2.1 Dilute Hydrochloric Acid — approximately 5 N  
J.2.2 Dilute Ammonium Hydroxide Solution — approximately 5 N  
J.2.3 Potassium Cyanide Solution — Dissolve 10 g of potassium cyanide  in 100 mL of water.  
J.2.4 Acetic Acid — glacial  
J.2.5 Hydrogen Sulphide Solution — saturated and freshly prepared.  
J.2.6 Standard Lead Solution — Dissolve 1.60 g of lead nitrate in  wate r and m ake up the 
solution to 1  000 mL. Dilute 10 mL of this solution to 1 000 mL. One millilitre o f the diluted 
solution contains 0.01 mg of lead (as Pb ). 
 
J.3 Procedure  
Transfer 20 mL of the sample solution ( A.2) to a Nessler cylinder, add 12 mL of hyd rochloric 
acid, 10 mL of dilute ammonium hydroxide solution and 1 mL of potassium cyanide solution 
and dilute to 40 mL. Add 5 mL of hydrog en sulphide solution, dilute to the mark and mix well. 
Carry out a control test usi ng 2 mL of standard lead solution, 1 mL of acetic acid a nd the same 
quantities of other reagents in the same total volume o f the reaction mixture. Compare the 
colour produced in both the cylinders after 5 minutes.  
 
J.4 The limit prescribed for heavy metals shall be taken as n ot having  been exceeded if any 
colour produced i n the test with the material is not deeper than that produced in the control test.  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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©TBS 2017 – All rights reserved      Second edition 2017  
  15 Annex K  
(Normative)  
 
Test for Arsenic  
 
 
Apparatus/Equipment and Materials  
a) X-ray fluorescence spectrometer (XRF): Consists of X -ray excitation source, means of 
sample presentation, X -ray detector, data processor and control system. There are two types 
of X-ray fluorescence spectrometers -- wavelength dispersive X -ray fluoresce nce spectrometer 
(WDXRF) and energy dispersive X -ray fluorescence spectrometer (EDXRF).  
 
Warning: Operation of analyzers generating or using X -ray radiation during operation, such as 
X-ray tube or radioisotope sources must be conducted in accordance with the manufacturer’s 
safety instructions and local regulations. If a radioactive source is used, it must be well shielded 
to international standard requirements and, therefore, not present any safety hazard. Attention 
to the source is only to be carried out by a fully trained, competent and authorized person using 
the correct shielding techniques.  
 
b) The analytical method should allow to distinguish between samples, which safely contain 
concentrations, which are below the tolerated values and those, which a re clearly higher than 
the tolerable values. In case, that this statement cannot be committed clearly, additional 
investigation with other analytical methods are necessary.  
 
c) Independent from the technique which is used, the following limits must be obs erved, where 
X marks the region, where further investigation is necessary. (The definition has to be confirmed 
by an inter laboratory study).  
 
The analyzer should be tested with substances with known composition in order to proof the 
performance. It is re commended to use minimum two test substances, where one should have 
concentrations of about 50 % of the lower limits and the second should have about 150 % of 
the upper limit