Auto-sampler

Abstract

An auto-sampler successively collects liquid samples from plural sample containers through a metallic needle. A surface of the needle is coated with a coating material having a chemical activity smaller than that of a parent metal material of the needle, and the coated surface is polished to have an average roughness of 10 to 20 nm. The coating material may include a precious metal or synthetic resin plated or deposited on the parent metal material, or a quartz thin film formed by chemical vapor deposition on the parent metal material. The coating film on the needle is polished with a mechanical or chemical polishing method.

1 . An auto-sampler for successively collecting liquid samples from plural sample containers, comprising: 
 a needle made of metal and coated with a coating material, said coating material having a chemical activity smaller than that of the metal and a polished surface having an average roughness of 10 to 20 nm.    
   
   
       2 . An auto-sampler according to  claim 1 , wherein said polished surface is made by mechanical polishing.  
   
   
       3 . An auto-sampler according to  claim 1 , wherein said polished surface is made by chemical polishing.  
   
   
       4 . An auto-sampler according to  claim 1 , wherein said coating material includes a precious metal.  
   
   
       5 . An auto-sampler according to  claim 1 , wherein said coating material includes a synthetic resin.  
   
   
       6 . An auto-sampler according to  claim 1 , wherein said coating material includes quartz.  
   
   
       7 . An auto-sampler according to  claim 1 , wherein said coating material has a thickness greater than the average roughness and less than several tens of μm.