Dear all   
      
   I am now having trouble on titration of an unknown Anionic surfactant. My   
   method is using Metrohm 904 titrando for surfactant titration. Mostly we   
   titrate a known formula anionic surfactant which is quite obvious to find an   
   end point and surfactant    
   content using Hyamine 1622 as titrant.    
      
   Recently, I have received the unknown surfactant sample from other company.   
   They cleary stated that it will be Anionic surfactant and their report said   
   they used Hyamine 1622 for titration. However, I have tried our methods to   
   determine anionic    
   surfactant content from that sample but it could not find any end point at   
   all. I mean the potential we detected from the sample has passed our potential   
   at usual end point (around 200 mV) every single time and no high signal drift   
   was observed. The    
   titration curves we obtained seem to show that there is no anionic surfactant   
   in the sample when using Hyamine 1622.   
      
   So I was confused and went for cationic method instead due to the fact that I   
   seen the solution became more turbid when I droped few Anionic titrant (SDS)   
   into the sample. The end point was observed when I tried Cationic method (I   
   was more confused). I    
   also tried a sample drop test which i monitor a change in potential when I   
   drop any sample into blank solution. Firstly SDS was test and potential was   
   decreased (SDS is anionic). Secondly Hyamine revealed a rise in potential as I   
   expected. Poly ethylene    
   glycol didn't have any effects on potential because it is non-ionic   
   surfactant. When I tried the unknown it gave a rise in potential as seen in   
   Hyamine.   
      
   Can I conclude that the sample I received isn't Anionic but Cantionic instead.   
   Do you have any suggestion on how can I characterized it correctly?    
      
   Thank you   
      
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