From: '''newspam'''@nezumi.demon.co.uk   
      
   On 05/11/2018 12:04, Oumati Asami wrote:   
      
   > Just wonder why people use buffer solutions, instead of distilled water,   
   > to calibrate PH meters. Can distilled water be used to calibrate PH   
   > meters for PH 7?   
      
   Buffer solutions are actively clamped to a reliable pH value.   
      
   Laboratory distilled water will typically measure as about pH 5 or even   
   as low as 4 if you are somewhere polluted with NOx and SO2 in the air.   
   It always dissolves some CO2 unless made and kept under nitrogen.   
      
   Don't take my word for it - measure your labs distilled water supply!   
      
   --   
   Regards,   
   Martin Brown   
      
   --- SoupGate-Win32 v1.05   
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