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Determination of Ammonia in Household CleanersAn Instrumental Analysis Experiment

Richard C. Graham1

Science Research Laboratory, United States Military Academy, West Point, ! 1"##$

Steven DePew

%epartment o& 'hemistry, United States Military Academy, West Point, ! 1"##$Many different kinds of solutions containammonia. Someof the most common types of preparations are the household cleaners. Ammonia has been shown to be an effectivegrease cutter, and thus, the presence of ammonia is a desirable addition to the formulation. Among the many differentmethods which have been used to determine ammonia is the Nessl er ization technique.!ne use of this technique is todetermine the amount of ammonia which is produced by certa in enz ymatic reactions. A ma"or problem with thistechnique is thepot ential int erf ere nce of many of the alkyl amines. A secondmethod which has been used to determine ammonia in soaps and detergents is the electrode method wherein a gas

perme able membrane combi nation electrode is used. #$ As with theNesslerization techn iqu e, many of the al kyl aminesinterfere with the method. A third common method in use is ion e%change chromatography &such as with the '(!N)*(on +hromatograph which actually determines the pre sence of ammonium ion.

-he disadvantages of each of these methods make it desirable to e%plore alternative methods. A method, which hasfound application for determination of weak &pfa/ 0 mono and polyprotic acids, is to monitor the heat producedduring a neutralization reaction.1-he equivalence point is noted by a sharpbre ak in the titration curve rather thaninflection point as with potentiometric monitoring of the titration. -hispro cedure is easily modified to determinequantitatively such analytes as ammonia in solution.

Experimental

-hermometric titration data were obtained with a (R)A' model 123 adiabatic titration calorimeter. -emperature in the water bath surroundingthe reaction vessel was maintained at 2.333 4+ 5 3.3336 4+ by a -7!NA+ model 8-+ temperature controller. 'ata were

taken by titrating 23 ml of an ammonia solution &diluted with freshly boiled deionized water to maintain the titration curve on scale with

a 3.19:9 Nsolution of hydrochloric acid. -he equivalence point was taken as the first sharp break which occurs in the titration run. See

the figure for a typical titration run.A total of four different household cleaners were e%amined.

Results and Discussion-he titration of the ammoniapre sent was assumed to fol low, for reasons of simplistic interpretation, eqns. &9 and(2):

N; 1!; 1.* 1!"#

(1)

0H- + H +^=H 2 0 1/KW =101 4 (2)

9Author to whom correspondence should be addressed. ?Standard Methods for the )%amination of @ater and @astewater,

91th )d., 7and, M. +., Breenberg, A. )., and Caras, M, C,, [Editors)American 8ublic ;ealth Association, @ashington, '.+., 1$%&.

6Analytical Methods Buide, :th )d., !rion (nstrument +o., +am