Titration of long‐chain quaternary ammonium compounds using tetraphenylboron

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Abstract
A rapid macro procedure for the determination of long‐chain quaternary ammonium compounds (QAC) has been developed using sodium tetraphenylboron as a titrant. About 1舑1.5 meq of QAC is dissolved or dispersed in 50 ml of water. Dichlorofluorescein is added as an indicator. The sample is then titrated with 0.06 N aqueous sodium tetraphenylboron. As long as free QAC is present the mixture will be pink. When the tetraphenylboron has reacted with all of the QAC, the indicator becomes yellow. The procedure has been used routinely to analyze both pure and commercial QAC with good results. The possible interferences include amine salts and potassium ion. The amine salt interference may be easily corrected or eliminated by changing the pH. The method has also been applied to the determination of a variety of quaternary ammonium salts having anions other than halides.