Various types of synthetic colorants are used as food additives, and gradient elution is generally used to analyze them. The Nexera UHPLC (Shimadzu) enables stable, ultrafast gradient elution through accurate solution delivery and the use of a high-efficiency gradient mixer.

This document introduces an example of ultrafast analysis performed on 12 tar synthetic colorants using Nexera and a Phenomenex Kinetex C18 column (particle size 2.6 μm, a core-shell column where a 0.35 μm porous membrane is combined with a 1.9 μm solid core).

Results

Analysis time was shortened to 1/20 of conventional analysis for standard mixtures (50 mg/L each) by using the Phenomenex Kinetex C18 column, which provides a higher linear flow rate. Good repeatability of retention time and peak area was also achieved, as shown in Table 1.

Experimental Conditions (Figure 1 top)

Column: Shim-pack VP-ODS (150 mmL. x 4.6 mmI.D., 4.6 μm)
Mobile Phase: A: 10 mmol/L Ammonium acetate; B: Mobile phase A/Acetonitrile=1/1
Gradient: B 5 % (0 min)?100 % (20-30 min)
Flow Rate: 1.0 mL/min (Mixer 180 μL)
Column Temp: 40°C
Injection Volume: 2 μL
Detection: UV-VIS (SPD-M20A) Max Plot 400-700 nm
Flow Cell: Conventional cell
Pressure: 8 MPa

Experimental Conditions (Figure 1 bottom)

Column: Phenomenex Kinetex 2.6 μm C18 100Å (50 mmL. x 3.0 mmI.D., 2.6 μm)
Mobile Phase: A: 10 mmol/L Ammonium acetate; B: Mobile phase A/Acetonitrile=1/1
Gradient: B 5 % (0 min)?100 % (1.1-1.6 min)
Flow Rate: 2.5 mL/min (Mixer 20 μL)
Column Temp: 40°C
Injection Volume: 1 μL
Detection: UV-VIS (SPD-M20A) Max Plot 400-700 nm
Flow Cell: Semi-micro cell
Pressure: 53 MPa

Table 1: Repeatability of Retention Time and Peak Area

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