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The determination of ammonia in natural waters
Water Research Vol. 10. pp. 567 to 50& Pergamon Press 1976. Printed m Great Britain.
NOTE THE DETERMINATION
OF AMMONIA
IN N A T U R A L WATERS*
M. I. LIDDICOAT. SUSAN TIBBITTS a n d E. I. BUTLER Marine Biological Association of the United Kingdom. The Laboratory. Citadel Hill. Plymouth. U.K.
The estimation of low concentrations of a m m o n i a in b o t h fresh and sea water has always proved difficult a n d several methods have been tried in this Laboratory with varying degrees of success. In 1973 a phenolhypochlorite method was developed here based o n a previously published method (Sol6rzano. 19691. The method has now been in routine use for more than a year giving consistent results and the procedure for use in sea water has been published in Limnol. Oceanog. (1975). The method is currently being used in a n u m b e r of laboratories in the analysis of both sea and fresh water with increasing popularity. With the experience so far gained it is now possible to make some helpful observations on the original method a n d these are presented here together with the procedure for use in fresh water. METHOD 1. De-ioni:ed water Prepare immediately before use by passing distilled water through a freshly charged cation exchange resin in the hydrogen form.
Reagents 2 and 3 are stable for at least 24 h when stored in a refrigerator but the catalyst must be prepared daily. To a 50 ml sample in a 100 ml Pyrex conical flask add 2 ml of phenolalcohol reagent, 5 ml of oxidising solution and 2 ml of catalyst, mixing between each addition. Cover the tops with glass or plastic caps and place within 0.5 m of a Hytek mercury lamp fitted with a reflector such that each flask receives maximum energy. Colour development is complete in 40 rain over a temperature range of 22-27"C. Measure the absorption at 640 nm in a spectrophotometer against distilled water using 10cm cuvettes. A calibration should be made with each batch of samples. As with all methods for the estimation of low concentrations of ammonia the risks of contamination are high. The work should be carried out in an ammonia free laboratory with acid washed glassware. The factor relating absorbance to concentration fin /.lgatoms NH3-N I -t} is 5.8 while in sea water it is 6.5. On sets of samples containing I and 4ug atoms NH3-N I-t (14 and 56pg NHa-NI -t) the S.D. were 0.02 and 0.04 respectively. Beer's law was obe)ed over the concentration range 0-20 ,~tg atoms NH3-N 1- I. DISCUSSION
The mercury lamp used by us was a Hytek type M B W with a m a x i m u m energy output at 365 nm. We found this lamp particularly convenient as being low 2. Phenol-alcohol reagent powered it could be used in the laboratory without Dissolve 10g of Analar phenol in 100ml of Analar 95% v v- t ethyl alcohol. great inconvenience. Initially it was used with an alum i n i u m reflector placed behind it so that maximum 3. Oxidising solution energy was concentrated o n samples placed 0.5 m Dissolve 0.2 g of sodium dichloroisocyanurate in a soluaway. Subsequently it was found to be more contion of 1.6g of Analar sodium hydroxide in 40 ml of devenient to place the lamp in the middle of an aluionized water. To this add a solution of 20 g Analar trisominium box. Samples were placed inside the box, the dium citrate in 40 ml of de-ionized water. Adjust volume to 100 ml with de-ionized water. all r o u n d reflecting surface making possible colour development in a large n u m b e r of samples at the 4. Catalyst same time. O t h e r laboratories have used different Dissolve 0.5g of Analar potassium ferrocyanide in types of u.v. lamps examples being a n Allen Pattern 100 ml of de-ionized water. Transfer to an amber bottle. 409 a n d the Baird & Tatlock u.v. lamp manufactured for use in thin layer chromatography. It appears that * Authors are invited to submit proved methods of various types of u.v. lamps are suitable and a laboraanalysis for water, wastewater, effluents and seawater. The tory using the method should initially test any u.v. methods should be concise but sufficient detail should be sources already available. given to allow the procedure to be followed. Slight modifications of existing methods should not be submitted. DeAn interesting modification to the method has been scriptions of new or developing instrumental techniques made by Dr. B. Bayne of the Institute for Marine or equipment for improving or accelerating existing techEnvironmental Research IPrivate communication). niques, or experiences in the field use of aids to monitoring, Changes can occur very quickly after taking samples such as specific ion electrodes will be accepted. Provided the Notes submitted are of interest to the wide readership containing low levels of a m m o n i a and preservation of Water Res. and do not exceed 1500 words they will is difficult. Samples should therefore be analysed as be published without delay. The correspondence columns speedily as possible. Dr. Bayne has overcome this difof Water Res. will be open to any reader wishing to comment on methods described in these Notes. Executive Edi- ficulty whilst working o n a small ship by developing the colour immediately after taking a n d filtering the tor. 567
568
Note
sample. The colour is stable for at least 6h under these conditions so that the samples can be transported back to the laboratory for measurement in a spectrophotometer. Sodium dichloroisocyanurate may be obtained from Sigma Chemical Company Ltd., Kingston upon Thames, Surrey, England.
REFERENCES
Liddicoat M. I., Tibbitts Susan & Butler E. I. (1975) The determination of ammonia in sea water. Limnol. Oceanoyr. 20(I). 131-132. Sol6rzano L. (1969) Determination of ammonia in natural waters by the phenolhypochlorite method. Limnol. Oceanoyr. 14, 799-801.
NOTE THE DETERMINATION
OF AMMONIA
IN N A T U R A L WATERS*
M. I. LIDDICOAT. SUSAN TIBBITTS a n d E. I. BUTLER Marine Biological Association of the United Kingdom. The Laboratory. Citadel Hill. Plymouth. U.K.
The estimation of low concentrations of a m m o n i a in b o t h fresh and sea water has always proved difficult a n d several methods have been tried in this Laboratory with varying degrees of success. In 1973 a phenolhypochlorite method was developed here based o n a previously published method (Sol6rzano. 19691. The method has now been in routine use for more than a year giving consistent results and the procedure for use in sea water has been published in Limnol. Oceanog. (1975). The method is currently being used in a n u m b e r of laboratories in the analysis of both sea and fresh water with increasing popularity. With the experience so far gained it is now possible to make some helpful observations on the original method a n d these are presented here together with the procedure for use in fresh water. METHOD 1. De-ioni:ed water Prepare immediately before use by passing distilled water through a freshly charged cation exchange resin in the hydrogen form.
Reagents 2 and 3 are stable for at least 24 h when stored in a refrigerator but the catalyst must be prepared daily. To a 50 ml sample in a 100 ml Pyrex conical flask add 2 ml of phenolalcohol reagent, 5 ml of oxidising solution and 2 ml of catalyst, mixing between each addition. Cover the tops with glass or plastic caps and place within 0.5 m of a Hytek mercury lamp fitted with a reflector such that each flask receives maximum energy. Colour development is complete in 40 rain over a temperature range of 22-27"C. Measure the absorption at 640 nm in a spectrophotometer against distilled water using 10cm cuvettes. A calibration should be made with each batch of samples. As with all methods for the estimation of low concentrations of ammonia the risks of contamination are high. The work should be carried out in an ammonia free laboratory with acid washed glassware. The factor relating absorbance to concentration fin /.lgatoms NH3-N I -t} is 5.8 while in sea water it is 6.5. On sets of samples containing I and 4ug atoms NH3-N I-t (14 and 56pg NHa-NI -t) the S.D. were 0.02 and 0.04 respectively. Beer's law was obe)ed over the concentration range 0-20 ,~tg atoms NH3-N 1- I. DISCUSSION
The mercury lamp used by us was a Hytek type M B W with a m a x i m u m energy output at 365 nm. We found this lamp particularly convenient as being low 2. Phenol-alcohol reagent powered it could be used in the laboratory without Dissolve 10g of Analar phenol in 100ml of Analar 95% v v- t ethyl alcohol. great inconvenience. Initially it was used with an alum i n i u m reflector placed behind it so that maximum 3. Oxidising solution energy was concentrated o n samples placed 0.5 m Dissolve 0.2 g of sodium dichloroisocyanurate in a soluaway. Subsequently it was found to be more contion of 1.6g of Analar sodium hydroxide in 40 ml of devenient to place the lamp in the middle of an aluionized water. To this add a solution of 20 g Analar trisominium box. Samples were placed inside the box, the dium citrate in 40 ml of de-ionized water. Adjust volume to 100 ml with de-ionized water. all r o u n d reflecting surface making possible colour development in a large n u m b e r of samples at the 4. Catalyst same time. O t h e r laboratories have used different Dissolve 0.5g of Analar potassium ferrocyanide in types of u.v. lamps examples being a n Allen Pattern 100 ml of de-ionized water. Transfer to an amber bottle. 409 a n d the Baird & Tatlock u.v. lamp manufactured for use in thin layer chromatography. It appears that * Authors are invited to submit proved methods of various types of u.v. lamps are suitable and a laboraanalysis for water, wastewater, effluents and seawater. The tory using the method should initially test any u.v. methods should be concise but sufficient detail should be sources already available. given to allow the procedure to be followed. Slight modifications of existing methods should not be submitted. DeAn interesting modification to the method has been scriptions of new or developing instrumental techniques made by Dr. B. Bayne of the Institute for Marine or equipment for improving or accelerating existing techEnvironmental Research IPrivate communication). niques, or experiences in the field use of aids to monitoring, Changes can occur very quickly after taking samples such as specific ion electrodes will be accepted. Provided the Notes submitted are of interest to the wide readership containing low levels of a m m o n i a and preservation of Water Res. and do not exceed 1500 words they will is difficult. Samples should therefore be analysed as be published without delay. The correspondence columns speedily as possible. Dr. Bayne has overcome this difof Water Res. will be open to any reader wishing to comment on methods described in these Notes. Executive Edi- ficulty whilst working o n a small ship by developing the colour immediately after taking a n d filtering the tor. 567
568
Note
sample. The colour is stable for at least 6h under these conditions so that the samples can be transported back to the laboratory for measurement in a spectrophotometer. Sodium dichloroisocyanurate may be obtained from Sigma Chemical Company Ltd., Kingston upon Thames, Surrey, England.
REFERENCES
Liddicoat M. I., Tibbitts Susan & Butler E. I. (1975) The determination of ammonia in sea water. Limnol. Oceanoyr. 20(I). 131-132. Sol6rzano L. (1969) Determination of ammonia in natural waters by the phenolhypochlorite method. Limnol. Oceanoyr. 14, 799-801.