Chromolith® RP-18 Endcapped HPLC Columns

Fast Separation at Lower Flow Rates

Chromolith Performance RP-18 endcapped HPLC columns are designed for rapid separations of more complex mixtures. The Chromolith® 3 mm internal-diameter column (length 100 mm) is an ideal alternative to conventional particulate columns with internal diameters of 4.6, 4 or 3 mm. Even difficult separations, which often take 15 to 30 minutes on particulate columns, typically take only 5 to 10 minutes on Chromolith® 3 mm i.d. 

Column Coupling

Chromolith® 3 mm i.d. columns can be easily coupled using the column coupler to form columns of 20 cm or longer as required. As shown in Tables 1 and 2, this results in very high peak resolution at moderate pressure with flow rates between 1 and 1.5 mL/min.

Chromolith® Performance RP-18e 100-3 mm

Column	Chromolith® Performance RP-18e 100-3 mm
Mobile Phase	Acetonitrile / buffer pH 1.8 (gradient)
Flow rate	2.0 mL/min
Pressure	92 bar
Detection	UV 254 nm
Temp.	30°C
Injection volume	1 μL
Sample	1. - 2. By-products 3. Levothyroxine 4. - 9. By-products>

Two coupled Chromolith® Performance RP-18e 100-3 mm

Column	Two coupled Chromolith® Performance RP-18 endcapped 100-3 mm
Mobile Phase	Acetonitrile / buffer pH 1.8 (gradient)
Flow rate	1.5 mL/min
Pressure	140 bar
Detection	UV 254 nm
Temp.	30°C
Injection volume	1 μL
Sample	1. - 2. By-products 3. Levothyroxine 4. - 9. By-products

Excellent Column Efficiency and Peak Resolution

Table 3 depicts a typical fast separation of four compounds in less than two minutes using a Chromolith® 4.6 mm i.d. column at a flow rate of 4 mL/min. The second example (Table 4) shows the same separation on a Chromolith® 3 mm i.d. column. Both chromatograms exhibit excellent column efficiency and peak resolution, however the 3 mm i.d. column demonstrates improved sensitivity at just 1.7 mL/min, thus saving 57% of solvents.

Chromolith® Performance RP-18e 100-4.6 mm

Column	Chromolith® Performance RP-18 endcapped 100-4.6 mm
Mobile Phase	Acetonitrile / water 40/60
Flow Rate	4.0 mL/min
Pressure	137 bar
Detection	UV 254 nm
Temp.	Ambient
Injection Volume	1 μL
Sample	1. Biphenyl-4.4 ’ -ol 2. Biphenyl-2.2 ’ -ol 3. Biphenyl-4-ol 4. Biphenyl-2-ol

Chromolith® Performance RP-18e 100-3 mm

Column	Chromolith® Performance RP-18e 100-3 mm
Mobile Phase	Acetonitrile / water 40/60
Flow Rate	1.7 mL/min
Pressure	100 bar
Detection	UV 254 nm 2.4 μL flow cell *
Temp.	Ambient
Injection Volume	1 μL *
Sample	1. Biphenyl-4.4 ' -ol 2. Biphenyl-2.2 ' -ol 3. Biphenyl-4-ol 4. Biphenyl-2-ol

* For optimum results with 3 mm i.d. columns, extra-column volume must be small.

Chromolith® RP-18 Endcapped 2 mm and 3mm Columns