FINAL DRAFT UGANDA 
STANDARD  
  FDUS 903 -2 
First Edition  
2011 -mm-dd 
 
 
 Reference number  
FDUS 903 -2: 2011 
© UNBS 2011   
  
Double -capped fluorescent l amps  — Performance 
Specification s — Part 2: Procedure for quantitative analysis of 
mercury present in fluorescent lamps  
 FDUS 903 -2: 2011  
ii © UNBS 2011  – All rights reserved  
 Compliance with this standard does not, of itself confer immunity from legal obligations  
A Uganda Standard  does not purport to include all necessary provisions of a contract. Users are 
responsible for its correct application  
© UNBS 2011   
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilised in any 
form or by  any means, electronic or mechanical, including photocopying and microfilm, without prior written 
permission from UNBS.  
Requests for permission to reproduce this document should be addressed to  
The Executive Director  
Uganda National Bureau of Standards  
P.O. Box 6329  
Kampala  
Uganda  
Tel: 256 41 4 505 995  
Fax: 256 41 4 286 123  
E-mail: unbs@infocom.co.ug  
Web: www.unbs.go.ug  FDUS 903 -2:2011  
© UNBS 2011  – All rights rese rved iii 
 Contents  Page 
Foreword  ................................ ................................ ................................ ................................ ...................... iv 
1 Scope  ................................ ................................ ................................ ................................ ................ 1 
2 Normative references  ................................ ................................ ................................ ....................... 1 
3 Terms and definitions  ................................ ................................ ................................ ...................... 1 
4 Test conditions  ................................ ................................ ................................ ................................ .3 
4.1 General ................................ ................................ ................................ ................................ .............. 3 
4.2 Measurement equipment ................................ ................................ ................................ .................. 3 
4.2.1  Preparation equipment required (dependent on the method employed)  ................................ .......3 
4.2.2  Reagents - Standar d procedure  ................................ ................................ ................................ .......4 
4.2.3  Equipment for amalgam procedures  ................................ ................................ ............................... 4 
4.2.4  Instrument ................................ ................................ ................................ ................................ ......... 5 
5 Test set -up ................................ ................................ ................................ ................................ ........ 5 
5.1 Lamps  ................................ ................................ ................................ ................................ ............... 5 
5.2 Laboratory conditions  ................................ ................................ ................................ ...................... 5 
5.3 Sample set -up ................................ ................................ ................................ ................................ ...6 
5.3.1  Lamps  ................................ ................................ ................................ ................................ ............... 6 
5.3.2  Containers  ................................ ................................ ................................ ................................ ........ 6 
5.3.3  Acids ................................ ................................ ................................ ................................ ................. 6 
5.3.4  Standard solutions  ................................ ................................ ................................ ........................... 6 
5.3.5  Preparation equipment  ................................ ................................ ................................ ..................... 6 
5.4 Measuring equipment set -up ................................ ................................ ................................ ........... 6 
6 Procedures  ................................ ................................ ................................ ................................ .......7 
6.1 General ................................ ................................ ................................ ................................ .............. 7 
6.2 Test methods  ................................ ................................ ................................ ................................ ....7 
6.2.1  Mercury decomposition in a lamp bulb not containing amalgams without breaking up the 
lamp (long linear lamp types).  ................................ ................................ ................................ ......... 7 
6.2.2  Mercury composition in a fluorescent light bulb after destruction of the bulb  ............................. 8 
6.3 Decomposition of mercury amalgams ................................ ................................ ............................. 9 
6.3.1  Titanium amalgam  ................................ ................................ ................................ ............................ 9 
6.3.2  Amalgam pellet and amalgam mesh  ................................ ................................ ..............................  10 
6.4 Samples for measurement  ................................ ................................ ................................ .............  11 
7 Measurement - Inductively coupled plasma -optical emission spectrophotometry  .....................  11 
7.1 Abstract  ................................ ................................ ................................ ................................ ..........  11 
7.2 Instrument ................................ ................................ ................................ ................................ ....... 11 
7.3 Setting of measuring conditions  ................................ ................................ ................................ ... 11 
7.4 Quantitative analysis from the ICP -OES  ................................ ................................ ........................  11 
8 Reporting  ................................ ................................ ................................ ................................ ........  13 
8.1 Recording  ................................ ................................ ................................ ................................ ....... 13 
8.2 Measurement uncertainty  ................................ ................................ ................................ ..............  13 
 FDUS 903 -2: 2011  
iv © UNBS 2011  – All rights reserved  
 Foreword  
Uganda National Bureau of Standards (UNBS) is a parastatal under the Ministry of Tourism, Trade and 
Industry established under Cap 327 , of the Laws of Uganda.  UNBS is mandated to co -ordinate the 
elaboration of standards and is  
(a) a member of International Organisation for Standardisation (ISO) and  
(b) a contact point for the WHO/FAO Codex Alimentarius Commission on Food Standards, and  
(c) the National Enquiry Point on TBT/SPS Agreements of the World Trade Organisation (WTO).  
The work of preparing Uganda Standards is carried out through Technical Committees. A Technical 
Committee is established to deliberate on standards in a given field or area and consists of representatives of 
consumers, traders, academicians, manufacturers, government and other stakeholders.  
Draft Uganda Standards adopted by the Technical Committee are widely circulated to stakeholders and the 
general public for comments. The committee reviews the comments before recommending the draft standards 
for approval and declara tion as Uganda Standards by the National Standards Council.  
Committee membership  
The following organizations were represented on the Energy Management  Technical Committee , UNBS/TC 
13, during the development of this standard:  
 Department of Mechanical Engine ering, Makerere University  
 Econoler  
 Electricity Regulatory Authority (ERA)  
 GTZ-Promotion of Renewable Energy and Energy Efficiency Programme (GTZ -PREEEP)  
 Ministry of Energy and Mineral Development  
 Private Sector Foundation Uganda (PSFU)  
 Uganda Manufacturer s’ Association (UMA)  
 Uganda National Bureau of Standards (UNBS)  
 Water and Electricity Consumers’ Association (WECA)  
 
The following organizations were represented on the Lighting Appliances Sub -committee of the Energy 
Management Technical Committee,  UNBS/T C 13, during the development of this standard:  
 Centre for Research in Energy and Energy Conservation (CREEC), Makerere University  
 Department of Electrical Engineering, Makerere University  
 Econoler   
 Industrial Technical Solutions (ITS) (U) Ltd  
 Kiboko Enterp rise (U) Ltd  
 Ministry of Works and Transport  
 Osram/Dembe Trading Co. Ltd  
 Uganda National Bureau of Standards (UNBS)  FDUS 903 -2:2011  
© UNBS 2011  – All rights rese rved v 
  Uganda National Chamber of Commerce and Industry (UNCCI)  
 Ultra -Tec Uganda Ltd  
 
 FINAL DRAFT UGANDA STANDARD  FDUS 903 -2: 2011  
 
© UNBS 2011 – All rights reserved  1 
 Double -capped fluorescent lamps  — Performance 
Specification s — Part 2: Procedure for quantitative analysis of 
mercury present in fluorescent lamps  
1 Scope  
1.1 This Final Draft Uganda Standard outlines a procedure for quantitative analysis of mercury present in 
fluorescent lamps that are used in general lighting se rvice and which are covered within the scope of US IEC 
60081  and US IEC 60901.  
The testing method specifies the procedures that can be used to determine accurately the mercury content in 
a fluorescent lamp in which mercury is introduced as the medium for d ischarge between the electrodes.  
The method involves the chemical digestion of the mercury contained within a lamp and the determination of 
that mercury content on a per unit basis. This is achieved using a method of solubilization of the entire 
mercury co ntent contained within the tube using acidic digestion methods and the accurate determination of 
that mercury content using standard mercury solutions. This will allow comparisons between lamps in batches 
and comparisons with other internationally accepted  standards for mercury content in fluorescent lamps.  
This standard covers methods of determination of mercury by wet chemical analysis.  
1.2 This standard does not apply to fluorescent lamps that are intended for special purposes as stated in 
1.2 of US 903 -1. 
1.3 This standard applies to fluorescent lamps that contain mercury in the form of vapour, liquid, oxidized 
liquid or in combination with amalgams.  
1.4 This standard is intended to be used together  with US IEC 60081  and US 903 -1 respectively . 
2 Normativ e references  
The following referenced documents are indispensable for the application of this document. For dated 
references, only the edition cited applies. For undated references, the latest edition of the referenced 
document (including any amendments) a pplies.  
US IEC 60081,  Double -capped fluorescent lamps  — Performance specifications  
US IEC 60901,  Single -capped fluorescent lamps  — Performance specifications  
US 903 -1, Double -capped fluorescent lamps  — Performance specifications  — Part 1 : Minimum Energy 
Performance Standard (MEPS)  
3 Terms and d efinitions  
For the purposes of this Standard, the definitions in  US 903-1, US IEC 60901 and the following definitions 
shall apply.  FDUS 903 -2: 2011  
2 © UNBS 2011 – All rights reserved  
 3.1 
aqua regia  
mixture of concentrated nitric acid (HNO3) and hydrochloric acid (HCl)  in a ratio of 1:3 by volume  
3.2 
discharge electrodes  
interior electrodes of a fluorescent lamp (grid or container), where mercury is present in the form of elemental 
mercury or amalgam. The discharge electrodes in the lamps are dependent on the type of la mp, that is, 
single - or double -capped lamps.  
3.3 
double -capped fluorescent lamp  
fluorescent lamp having two separate caps and mostly of tubular form and linear shape  
3.4 
fluorescent lamp  
discharge lamp of the low pressure type, in which most of the light i s emitted by one of several layers of 
phosphors excited by the ultra -violet radiation from the discharge from the electrodes  
3.5 
ICP-OES 
Inductively Coupled Plasma optical emission spectrophotometer used for the determination of mercury 
content in the fina l sample  
3.6 
lamp samples  
minimum of three lamps shall be chosen from an identical manufacturing run for each specific type of lamp.  
NOTE 1 Lamps of different types or brightness or size or wattage should not be mixed in any batch.  
NOTE  2 Separate batches of three lamps may be determined together as long as the lamps are clearly identified in 
their respective batches.  
3.7 
measurement equipment  
equipment used for measuring and preparing the sample for determination of mercury  
3.8 
primary check test  
mercury p resent in the fluorescent lamp determined using ten identical lamps for initial accuracy.  If the 
measurement of uncertainty is within acceptable limits (±  Q mg), then secondary check test as in 3.9 shall 
apply , where Q is the amount of mercury.  
3.9 
seconda ry check test  
mercury present in the fluorescent lamp shall be determined using lamp samples as in Clause 1.5.6. The 
arithmetic mean value is determined and shall be the stated quantity of mercury present in the fluorescent 
lamp. The value shall be express ed in two significant digits.  
A calibration shall be carried out prior to the actual check test in order to ensure that calibration value has no 
influence on the measurement value.  
3.10 
single -capped fluorescent lamp  
fluorescent lamp with a single type of cap but with the discharge tube bent or formed into a spiral or 
convoluted tube, made to fit into a smaller lamp base or socket  
NOTE These lamps may or may not contain mercury as amalgams. See 4.1.  
 FDUS 903-2: 2011  
© UNBS 2011  – All rights reserved  3 
 4 Test conditions  
4.1 General  
Test conditions are set up  to determine the mercury content in a batch of lamps in accordance with 3.6. The 
lamps for this purpose shall be clearly marked and identified by the supplier for each type of lamp, where the 
mercury content is to be determined.  
Initially, this is perfor med by breaking the lamp under controlled and captive conditions or by breaking the 
vacuum seal of the lamp to allow the interior contents to be accessed.  
All procedures shall take place in a controlled environment in a certified chemical laboratory, which  shall be 
equipped for the handling of hot acids, mercury and glass materials using appropriate fume cupboards and 
other hazard protection equipment.  
Safety precautions shall be taken for  
a) the protection of the laboratory analyst , 
b) the destruction of the lam ps, and 
c) the handling of mercury and any other phosphor content of the lamps.  
All types of wastes, including mercury wastes, shall be disposed of using proper disposal procedures.  
The mercury in the lamps is generally free mercury or mercury vapour under di scharge which provides the 
conducting medium between the electrodes. The discharge electrode in general purpose lamps is made of 
tungsten wire, but in some other types of lamps may contain a grid or container in which a mercury amalgam 
is present. The elec trodes are fitted to or moulded into cement, metal and plastic bases.  
Mercury in fluorescent lamps may exist in three possible states as follows:  
a) vapour in a lamp ; 
b) liquid metal or in an oxidized state ; or 
c) an amalgam of mercury with another metal such as Ti tanium (Ti), or Bismuth (Bi).  
This method determines the total amount of mercury present in either liquid metal or in  oxidized state or in an 
amalgam. Mercury in the vapour state is not determined since it  represents an insignificant proportion and for 
all practical purposes is ignored in the  determination procedures.   
Prior to the start of the analysis it shall be determined whether the lamp contains a mercury  amalgam. This is 
in order that the correct digestion procedure(s) are used.  
The total mercury in the lamp is determined by dissolving the entire mercury content from  the interior of the 
lamp in any of its forms in a suitable acid mixture.  
The ICP -OES then measures the mercury in the dissolved acid mixture taking account of  the actual volume of 
acid us ed. The mercury readings from the emission spectra are then  calculated against standard mercury 
solutions to calculate the actual mercury content for  each lamp or batch of lamps. The mean value for the 
three lamps is then used to determine  the mercury pres ent for each type of lamp.  
4.2 Measurement equipment  
4.2.1 Preparation equipment required (dependent on the method employed)  
4.2.1 .1 Pliers and sharp knife  FDUS 903 -2: 2011  
4 © UNBS 2011 – All rights reserved  
 4.2.1 .2 Beakers, volumetric flasks, measuring cylinders  
4.2.1 .3 Disposable 3 m L plastic transfer pip ettes  
4.2.1.4  Putty or plasticine or (similar)  
4.2.1.5  Automatic pipettors  to dispense specific volumes and disposable tips  
4.2.1 .6 0.45 micron filters suitable for acid solutions of up to 200 ml  
4.2.1 .7 Glass scoring file, heating wire and heater, hammer  
4.2.1.8  Electric hot plate  suitable for heating the acid in the bulb itself, or beaker  
4.2.1 .9 Safety gloves ( Teflon type)  
4.2.1.10  Acid -protective equipment, gloves, safety glasses and laboratory coat  
4.2.2 Reagents  - Standard procedure  
4.2.2.1  Nitric aci d (HNO 3), Concentrated, 70  % 
4.2.2.2  Water , High grade distilled water or Milli-Q 
4.2.2.3  Dilute nitric acid (1:1 ratio by volume) , equal volumes of 70  % nitric acid and water . The nitric 
acid shall be added to the water and mixed.  
CAUTION : A high amount o f heat transfer occurs during mixing. Always add acid to water.  
4.2.2.4  Standard solution of mercury salts , that is 1000 mg/ L mercuric nitrate from licensed sources  
4.2.2.5  Standard mercury solution , diluted in deionized water  
NOTE Standard mercury solutio n should be diluted on the day of measurement.  
4.2.3 Equipment for amalgam procedures  
4.2.3. 1 Additional reagents for more complex amalgam procedures (see specific method required)  
4.2.3.1 .1 Hydrochloric acid (HCl ), concentrated, 37  %. 
4.2.3.1 .2 Aqua regia , concentrated nitric acid is mixed with three times the volume of concentrated 
hydrochloric acid. Use caution while preparing this solution.  
4.2.3.1 .3 Sulphuric acid (H 2SO 4), concentrated, 98  %.  
4.2.3.1 .4 Sulphuric acid (1:1 ratio by volume) , equal  volum es of sulphuric acid and water.  
CAUTION : A high amount of heat transfer occurs during mixing. Always add acid to water.  
NOTE All chemicals should  be high quality analytical reagent (AR) grade.  
4.2.3. 2 Other additional equipment for amalgam procedures  
4.2.3 .2.1 Round -bottomed flask of type suitable for reflux procedures , which includes one glass -
stoppered side arm.  
4.2.3.2.2  Reflux condenser  FDUS 903-2: 2011  
© UNBS 2011  – All rights reserved  5 
 4.2.3.2.3  Electric heating mantle  for round -bottomed flask for refluxing.  
4.2.4 Instrument  
4.2.4 .1 Inductively coupled  plasma optical emission spectrometer (ICP -OES) , the instrument which 
gives light emission intensity with suitable sensitivity and stability in the directed measurement and 
concentration range for detection of the mercury emission spectra.  
NOTE  1 Refer to the specific operating manual for an ICP -OES.  
NOTE  2 A number of manufacturers supply suitable instruments.  
NOTE  3 ICP-OES are available in suitably equipped inorganic chemistry laboratories.  
4.2.4 .2 High quality pure, inert Argon gas  is used as the princi pal carrying gas for the plasma torch of 
the instrument  
An example of the principle of an ICP -OES is shown in Figure 1 . 
 
Figure 1  — Spectrophotometry part using sequential type spectroscope (an example)  
5 Test set-up 
5.1 Lamps  
Obtain a selection of lamps for testing, with a batch size as stated in Clause 3.6 of identical type. Groups of 
batches of lamps separately labeled may be tested in parallel, provided all samples are separately 
identified/marked and recorded throughout the determination procedure. Th ese should be clearly labeled as 
samples for test.  
5.2 Laboratory conditions  
The laboratory shall be suitably equipped with facilities for separate wet chemistry preparation areas. Mercury 
preparations and acids shall be handled and prepared in an acid sui table, fume cupboard and preparation 
area. Lamps shall not be broken or treated in a laboratory where other mercury determinations are being 
made.  FDUS 903 -2: 2011  
6 © UNBS 2011 – All rights reserved  
 NOTE Broken mercury lamps can discharge mercury into the atmosphere and severely compromise other sensitive 
mercury testing equipment.  
All laboratories shall have adequate safety equipment including the following:  
a) eye wash stations ; 
b) safety showers ; 
c) acid-protective equipment ; 
d) safety gloves ; and  
e) safety glasses.  
Procedures and equipment for disposal of all materials , glass, metal and acids shall be provided.  
5.3 Sample set -up 
5.3.1 Lamps  
All lamps to be tested shall be labeled and all manufacturers’ marks recorded onto separate test sheets 
clearly identifying each lamp type.  
5.3.2 Containers  
All beakers, flasks or sa mple tubes or plastic containers or bags used for holding the lamps (broken or 
otherwise) or tubes containing acid digestions for determination shall be separately labeled and recorded on 
test sheets.  
5.3.3 Acids  
All acids required, dilutions or mixtures o f acids shall be prepared in the fume cupboard and separately 
labeled and recorded on test sheets.  
5.3.4 Standard solutions  
All standard solutions for measurement and determination of concentration shall be separately prepared and 
recorded on test sheets.  
5.3.5 Preparation equipment  
All minor equipment, glassware , heating and plastic equipment shall be collected, prepared and tested to 
ensure its reliability, accuracy and functionality.  
All measuring equipment (see 4.2.1) shall be checked to ensure that acc urate volumes are delivered, with the 
results maintained and recorded on separate laboratory test sheets.  
5.4 Measuring equipment set -up 
The ICP -OES used for measuring the concentration of mercury in the final sample solutions shall be 
separately maintain ed according to the manufacturer’s specifications. The maintenance checks and records of 
the instrument’s performance in measuring the various elements is usually a routine procedure of the 
laboratory measuring the elements. These routine quality procedure s are to be adhered to in the laboratory 
and the instrument checked for accuracy and reliability of measurement for the mercury emission spectra 
using the standard procedures in place for the ICP -OES instrument.  FDUS 903-2: 2011  
© UNBS 2011  – All rights reserved  7 
 Appropriate procedures for the automatic sam pling equipment and argon gas supplies are also to be checked 
according to routine daily laboratory procedures.  
6 Procedures  
6.1 General  
The test method options for determination of mercury in fluorescent lamps are based on the medium by which 
mercury is p resent i.e. simple elemental mercury or mercury in amalgams. The former requires a relatively 
simple procedure while the latter requires more complex procedures. The method also depends on the type of 
lamp, where there is a possible means to introduce acid  into the bulb or the option lies only in the breakage of 
the bulb. This will be dependent on the type of lamp.  
Fluorescent lamps not containing amalgams shall be tested in accordance with the method stated in either 
Clause 6.2.1 or 6.2.2. Fluorescent lamp s with amalgam shall be tested in accordance with the method stated 
in Clause 6.2.2.  
6.2 Test methods  
6.2.1 Mercury decomposition in a lamp bulb not containing amalgams without breaking up the lamp 
(long linear lamp types).  
6.2.1 .1 Carefully remove the met al caps of the fluorescent tubes using a pair of pliers with a twisting 
action while holding the tube wrapped in paper towel to prevent glass injury.  
NOTE The cap should break the cement and the wires will break away.  
At one end of the tube break the small  central inner glass tube used to evacuate the tube originally by 
breaking it carefully with the pliers. Air will rush back into the tube.  
6.2.1 .2 Introduce diluted nitric acid ( see 4.2.2 .3) into the lamp ( for example,  30 m L into 40 W lamp) using 
a 3 m L plastic transfer pipette, rotating the tube as the acid is introduced 3 m L at a time until the 30 m L is 
inside the tube. The phosphor will wash off the inside of the tube.  
6.2.1 .3 Plug the broken end of the evacuation tube with a small amount of putty, plast icine or similar and 
invert the tube several times to wash the insides of the tube and filaments so that all phosphor is removed. 
Introduce the lamp vertically onto the hot plate ( see 4.2.1.8 ) preheated to 80  °C to 100  °C and heat for 40  min 
to 50 min. Inv ert the tube every 10 min to 15 min to ensure that the filament parts at the top end of the lamp 
are washed in hot nitric acid.  
NOTE After 50 min all the mercury in the lamp should be completely dissolved.  
6.2.1 .4 Hold the lamp over a beaker and again care fully break the evacuation tube at the other bottom 
end of the tube with pliers and allow the solution to run into the beaker.  
6.2.1 .5 Introduce another 20 m L of diluted nitric acid into the lamp through the upper evacuation tube 
while holding over the bea ker, rotating the tube to ensure all the inside is washed. Hold the tube horizontally 
and rotate carefully then allow the solution to run into the beaker. Wash the tube with a further 20 m L of water 
ensuring that all parts of the tube are washed thoroughly . Collect all washes.  
Note: The final volume should be less than 200 m L. 
6.2.1 .6 Filter the final solution through a 0.45 micron filter and make up to a volume of 200 m L in a 
volumetric flask with water according to Clause 4.2.2 .2. 
6.2.1 .7 Analyse appropri ate samples using ICP -OES, diluting the final solution as required.  FDUS 903 -2: 2011  
8 © UNBS 2011 – All rights reserved  
 6.2.2 Mercury composition in a fluorescent light bulb after destruction of the bulb  
6.2.2.1  Use a knife or pliers, to remove the plastic base and base cement from the bulb.  
6.2.2. 2 Score t he bulb with an appropriate glass scoring file on or near the end of the tube.  
6.2.2. 3 Heat a glass rod or nickel/chromium wire to red heat and touch the score line to crack the bulb; 
allow the lamp bulb to be exposed to atmospheric pressure.  
6.2.2. 4 Remov e the amalgams from the inside of the tube and dissolve them in accordance with 6.3.  
6.2.2. 5 Wet all of inside of the bulb with water in order to prevent losing mercury contained in the dry 
phosphor coating when the bulb is broken into pieces. Collect the water in a beaker.  
6.2.2. 6 Place the bulb in a thick plastic bag and break : 
(i) from outside the plastic bag using a hammer or heavy object (see Figure 2); or  
(ii) from inside the plastic bag, in a beaker (or similar container) using pincers or pliers.  
NOTE  An alte rnative method that can be used is to use a suitable glass or plastic flask or other lidded 
container in which to break the pieces, then smash the contents further with a large porcelain or glass ball (toy 
marble).  
Either method is intended to minimize inj ury to the operator as well as contain all pieces  of glass. Ensure 
complete digestion of all the contents.  
6.2.2. 7 Tip all the pieces from the bag into a beaker and rinse inside the plastic bag or container with 
known amount of water.  
6.2.2. 8 Prepare a vol ume of solution in the beaker containing water with concentrated nitric acid (1:1 ratio 
by volume) about 30 ml. Stir or wash the pieces around the container with a glass rod until no more  phosphor 
comes off from the pieces of glass. Heat the beaker on a h ot plate and maintain temperature of  about 80 °C 
for 40  min to 50 min.  
6.2.2. 9 Cool the solution to room temperature. Filter through a 0.45 micron filter. Transfer the filtrate and 
filter washings into a volumetric flask and water added to make up to an a ppropriate volume (see Notes).  
NOTE 1 This sample solution can be stored for a week, however diluted test solutions should be used for 
measurement only for the date of preparation.  
NOTE  2 The amount of diluent depends on the size and shape of the lamp, sin ce the mercury content of the lamp tube 
with the amalgam removed from the lamp may be very small, the amount of diluent should be small as possible.  
NOTE 3 In the case of a lamp containing an amalgam do not prepare the full final volume until the solution from Clause 
6.3 is added to the flask.  FDUS 903-2: 2011  
© UNBS 2011  – All rights reserved  9 
  
 
  
Figure 2  — Lamp destruction using the plastic Bag Method  
6.3 Decomposition of mercury amalgams  
6.3.1 Titanium amalgam  
6.3.1. 1 General  
An example of a titanium amalgam contained in a fluorescent lamp electrode is s hown in Figure 3.  
 
 
Figure 3 — Example of Titanium Amalgam in a fluorescent lamp  
6.3.1. 2 Decomposition of a titanium amalgam to determine the mercury  
6.3.1.2 .1 Take amalgam with metal ring from inside the lamp and place in a round -bottomed flask.  
6.3.1.2 .2 Connect a reflux condenser to the round -bottomed flask, place into a heating mantle which is 
placed in a  fume cupboard. Ensure that enough cooling water is flowing through the condenser.  FDUS 903 -2: 2011  
10 © UNBS 2011 – All rights reserved  
 6.3.1.2 .3 Add 10 ml of dilute sulphuric acid (1:1 ratio by volume)  through the side arm and heat gently for 
30 min.  
6.3.1.2 .4 Add 5 ml of dilute nitric acid (1:1 ratio by volume) through the side arm and heat until white fumes 
are observed.  
6.3.1.2 .5  Add a further 5 ml of dilute nitric acid (1:1 ratio by volume) through  the side arm and heat until 
the residual salts that formed have completely dissolved.  
6.3.1.2 .6 Cool the solution to room temperature. Filter through a 0.45 micron filter. Transfer the filtrate and 
filter washings into a volumetric flask, adding water to a known volume.  
If the amalgam is within a bulb, add this filtered solution to that of the solution obtained from the digestion of 
the remainder of lamps contained in the volumetric flask.  
6.3.2 Amalgam pellet and amalgam mesh  
6.3.2.1  General  
An example of  amalgam pellets and amalgam mesh contained in a fluore scent lamp are shown in Figure 4. 
 
 
 
Figure 4 — Examples of amalgam pellets and amalgam mesh contained in fluorescent lamps  
6.3.2. 2 Decomposition of amalgam pellets to determine the mercury  
6.3.2. 2.1 Using a knife or pliers as appropriate, remove the fluorescent lamp carefully from the plastic 
housing.  
6.3.2. 2.2 Let the fluorescent lamp be exposed to atmosphere using procedure described in 6.2.2 .3; break 
open the tube and take out the amalgam pellet an d the amalgam mesh from the fluorescent lamp.  
6.3.2. 2.3 Place in a beaker and add 10 m L of aqua regia.  
6.3.2. 2.4 Heat for 90 min at 80  °C. FDUS 903-2: 2011  
© UNBS 2011  – All rights reserved  11 
 6.3.2. 2.5 Cool the sample solution to room temperature. Filter through a 0.45 micron filter and transfer to 
an approp riate volumetric flask. Rinse the filter with water thoroughly and add water to marked line of a  
volumetric flask to prepare a test solution.  
NOTE When the solution contains bismuth, deposition of bismuth may occur in accordance with acidity. Ensure aqua 
regia concentration exceeds 10  % of the total volume within the volumetric flask.  
6.4 Samples for measurement  
All samples are then transferred to 15 m L plastic tubes in an appropriate sample volume to the automated 
sampler on the ICP -OES. The volumes are re corded and appropriate calibrations, duplicates and standard 
dilutions added to the sampling rack . 
7 Measurement  - Inductively coupled plasma -optical emission spectrophotometry  
7.1 Abstract  
After dissolving mercury from the lamp and/or amalgams by using ni tric acid or other acids, the insoluble 
components are removed by filtering, and the filtered solution made up to an appropriate volume. The 
appropriately diluted sample solutions are sprayed into plasma on the ICP -OES and the intensity of optical 
emission  of mercury is measured and the mercury concentration for the whole lamp determined using 
procedures developed for the instrument.  
7.2 Instrument  
7.2.1 ICP-OES , the instrument that gives light emission intensity with suitable sensitivity and stability in 
the directed measurement and concentration range. This type of instrument is available through several 
manufacturers.  
7.2.2 Gas, pure inert Argon gas as carrier gas into the plasma  
NOTE  See Figure 1 for principle of ICP -OES.  
7.3 Setting of measuring conditi ons 
These parameters are determined by the trained instrument operator according to normal measurement 
conditions prevalent for the instrument at that time.  
There is a possibility of hysteresis effect when a low mercury concentration sample is measured aft er a high 
mercury concentration sample. To avoid the hysteresis effect, ensure that the rinse time is adequate. This is 
confirmed by analysing known standard solutions and determining that the concentration assayed is correct.  
NOTE Plasma output, photometr ic height, flow rate of carrier gas, etc. are varied to set for optimum conditions.  
7.4 Quantitative analysis from the ICP -OES  
7.4.1 Select the mercury analytical line at wavelength of 194.2 nanometres (nm) for measuring light 
emission intensity. When spe ctral interference is found not to exist, the analytical line at 253.7 nm or the other 
spectral line may be used.  
7.4.2 As any coexisting elements other than mercury in the sample solution could have spectral 
interference on the mercury analytical line, a mercury spectral line without spectral interference should be 
selected by scanning around the mercury analytical line with spraying sample solution into the plasma (see 
Note 1).  
7.4.3 To avoid any effects of the phosphor in the matrix, a standard addition method should be used 
(see Note 2). At least four solutions are sampled by an equal amount from the test solution to prepare one FDUS 903 -2: 2011  
12 © UNBS 2011 – All rights reserved  
 kind of solution wherein the mercury element is not added and at least three kinds of solutions wherein the 
mercury element is added respectively at different concentrations.  
7.4.4 The solutions are sprayed into the plasma and the intensity of atomic emission of mercury is 
measured. The relation curve between the light emission intensity of the mercury element in the test solution  
is obtained from the intercept on the axis of abscissa (concentration).  
Calculate the amount of mercury in the florescent lamp with the following formula:  
 
where 
 
W is the amount of mercury , in milligrams,  in fluorescent lamp (mg)  
A is the  dilution rate  
C is the  mercury concentration of test solution  in micrograms Mercury per millilitre  (μg Hg/ml)  
V is the  amount of test solution in millilitres  
NOTE 1 As the line spectrum and continuous spectrum by a plasma -composing component and a  coexisting element 
are occasionally superimposed with each other for the analytical line as  spectral inter ference, it is recommended that an 
analytical line with no spectral interference  should be used. When spectral interference exists, the degree of the 
interference calculated as  the concentration of mercury should be less than 1/100 of the concentration of mercury of the  
test solution by using a synthetic matrix solution.  
NOTE 2  This method can be applied only to the case of no spectral interference, or where the  background and the 
spectral interference are regularly corrected and the calibration line  betwee n the light emission intensity and the 
concentration remains linear in the low  concentration area or area required for measurement (see Figure 5).  
 
 
Figure 5 — Method of obtaining concentration by Standard additional method  FDUS 903-2: 2011  
© UNBS 2011  – All rights reserved  13 
 8 Reporting  
8.1 Recording  
Recor d results from the measurement of solutions and all calculations on test sheets. The results are 
determined for the milligram amounts of mercury per lamp as an average of the three lamps used to 
determine the concentration for each particular type of lamp.  All results expressed as milligrams mercury per 
lamp should be recorded on a suitable report. The results should also contain the quality report determination 
of the results of any calibrations or standards measured in the same determination. Results and calculations 
should be verified by an alternate chemist.  
8.2 Measurement uncertainty  
Ideally the three determinations of mercury per lamp should show good agreement with a measurement 
uncertainty of <  10 %. The standard deviation for the measurement can be  determined from the 
measurements where there is good agreement in the three results. If there is no good agreement, the 
measurement uncertainty will be large and this may require that more than three lamps of the same type ( for 
example,  10 lamps) need to be tested to better the standard deviation. Alternatively, poor agreement of three 
mercury results with the same type of lamp from the same manufactured batch may indicate uneven injection 
of mercury into each lamp and poor manufacturing practice  
 
 FDUS 903 -2: 2011 
© UNBS 2011 – All rights reserved  15 
 Certif ication marking  
Products that conform to Uganda standards may be marked with Uganda National Bureau of Standards 
(UNBS) Certification Mark shown in the figure below.  
The use of the UNBS Certification Mark is governed by the Standards Act, and the Regulati ons made 
thereunder. This mark can be used only by those licensed under the certification mark scheme operated by 
the Uganda National Bureau of Standards and in conjunction with the relevant Uganda Standard. The 
presence of this mark on a product or in rel ation to a product is an assurance that the goods comply with the 
requirements of that standard under a system of supervision, control and testing in accordance with the 
certification mark scheme of the Uganda National Bureau of Standards. UNBS marked prod ucts are 
continually checked by UNBS for conformity to that standard.  
Further particulars of the terms and conditions of licensing may be obtained from the Director, Uganda 
National Bureau of Standards.  
 
 FDUS 903-2: 2011    
 
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© UNBS 2010 – All rights reserved