To achieve the very best results in modern HPLC...
   
For making use of microbore, capillary and high speed liquid chromatography only minor hardware changes are needed, resp. „conditio sine qua non". Critical components include:
  • small flow cells with appropriate internal volume and pathlength
  • connecting capillaries (nearly dead volume-free) as short as possible,
  • low dispersion column hardware guaranteeing maximum of chromatographical performance
  • flow splitter or high performance, low µl/min pump
    

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Note!

It is seriously recommended to use exlusively capillaries with fitting adapters and quick-connectors rather than with ferrule-type fittings
    

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Same chromatographical conditions, exept …
analytical flow cell with (9 µl / 6mm) with
inlet capillariy as supplied by manufacturer		 analytical flow cell (9 µl / 6mm) with fitting adapter capillaries (100 x 0.12 mm) capillary flow cell (0.1 µl / 0.3 mm) with fused silica inlet
     
Different Flow Cells – Influence of Volume and Pathlength
      
Cell Volume [µl] Pathlength
[mm ]		 Sensitivity
[AU ]		 Resolution
(1st +2nd peak)		 N/m
(5th peak )		 Assymetry factor
(5th Peak )
15 10 0.030 1.3 91 800 2.9
9 6 0.023 1.4 116 700 2.5
5 6 0.025 1.55 131 600 2.6
1.2 3 0.013 1.7 139 600 2.1
1.2* 4 0.016 2.6 118 800 1.1
0.0009* 8 0.008 3.3 164 500 1.2
  
Stationary phase: GROM SIL 100 ODS-2 FE; Column: 33 x 2.0 mm; Linear velocity 0.8 mm/s; Eluent: ACN:H 2 O =65:35; each flow cell connected via quick-connector (100 x 0.1 mm stainless steel capillary), *except capillary flowcells (150 mm x 100 µm "fused-silica"-capillaries); Injection: 1 µl benzoate test sample (dil.1:100)
   

Note!

experiments always have to be done at optimal linear velocity
   
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* High speed liquid chromatography (HSLC)