NUCLEODUR® silica with 1.8 µm particle size
Miniaturization in HPLC has a long history. It started in the early stage of HPLC development with the reduction of particle size from 10 µm via 7 μm to standard 5 µm – which is still the most widely used particle diameter in analytical HPLC – to 3 µm spherical particles which so far was the smallest particle size available for gaining higher theoretical plates and efficiencies.
With the introduction of the 1.8 µm NUCLEODUR® particles researchers have turned over an exciting leaf in HPLC column technology.
Features of 1.8 µm NUCLEODUR® particles |
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Increase of separation efficiency by higher number of theoretical plates (N):
50 x 4.6 mm NUCLEODUR® C18 Gravity |
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3 µm: |
N ≥ 100 000 plates/m (h value ≤ 10) |
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1.8 µm: |
N ≥ 166 667 plates/m (h value ≤ 6) |
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Increase of the plate number by ~ 67 % offers the possibility of using shorter columns with equal plate numbers resulting in a decrease of analysis time. |
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Significant improvement in resolution
Use of 1.8 μm instead of 3 µm particles leads to an increase of resolution by a factor 1.29 (29 %) |
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Higher flow rates and shorter run times
Optimal flow rate for 1.8 µm particles is higher than for 3 and 5 µm particles – the flow rate should be at the van-Deemter minimum. |
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Van-Deemter plot
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Column back pressure
Due to the smaller particle size the back pressure will increase.
Because of the high sphericity of the NUCLEODUR® particles and the very narrow particle size distribution we are able to keep the back pressure on a moderate level.
Thus NUCLEODUR® columns can be used on modernen ultra fast HPLC instruments as well as in combination with conventional HPLC systems with pumps up to 400 bar.
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| Comparison of back pressures |
| Eluent: |
100 % methanol |
| Flow rate: |
1.5 mL/min |
| Temperature: |
22 °C |
| Column dimensions: |
50 x 4.6 mm |
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NUCLEODUR® C18 Gravity |
Competitor |
| 3 µm |
70 bar |
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| 1.8 µm |
130 bar |
170 bar |
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Technical requirements
To gain the best result in ultra fast HPLC based on 1.8 μm particles certain technical demands on the instrument are made. |
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 Pumps for pressures of 250–1000 bar Flow rates of 2–3 mL/min Minimized dead volumes of the LC system Fast data recording |
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Versatile selectivities
All NUCLEODUR® premium phases are available with 1.8 µm particles: |
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