Analysis of Aldehydes using Post-Column Derivatization by High Performance Liquid Chromatography

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Introduction

It is becoming a big concern that aldehydes such as the formaldehyde and acetaldehyde act as an environmental pollutant that may contaminate the atmosphere, lakes, marshes, reservoirs, and rivers. Therefore, aldehydes are subject to various regulations like the Air Pollution Control Law, Water Supply Law, and Offensive Odor Control Law in Japan. As a method to measure aldehydes using HPLC, the pre-column derivatization method by 2,4- DNPH is well known, but this requires pretreatment such as sample collection, condensation and extraction before analysis. JASCO has introduced the analysis of formaldehyde and acetaldehyde by the post column fluorescence derivatization method using 1,3- Cyclohexanedione as a derivatizing reagent which doesn’t need such pretreatment.

The two above mentioned aldehydes and three others, propyl aldehyde, butyraldehyde, and valeraldehyde were analyzed simultaneously.

Jasco CO2 Delivery Pump: PU-2080-CO2

Experimental

Result

In figure 1, the 1,3-Cyclohexanedione reaction during the post column derivatization method is shown and figure 2 illustrates flow diagram for the HPLC.

Figure 1. 1,3-Cyclohexanedione reaction formula of post column derivatization method

No.1 : Eluent
No.2 : Degasser (DG-2080-53)
No.3 : Pump for eluent (PU-2080)
No.4 : Autosampler (AS-2057)
No.5 : Column oven (CO-2060)
No.6 : Column (Shodex RSpak KC-811 6E)
No.7 : Reagent
No.8 : Pump for reagent (PU-2085)
No.9 : Reaction oven (RO-2061)
No.10: Reaction coil
No.11: Cooling coil
No.12: Fluorescence detector (FP-2020)
No.13: Backpressure coil

Figure 3. Chromatogram of 5 aldehydes and minimum detectable amount of each. 1: Formaldehyde (0.091 ng), 2: Acetaldehyde (0.105 ng), 3: Propylaldehyde (0.418 ng), 4: Butylaldehyde (0.593 ng), 5: Valeraldehyde (4.53 ng)

About the Author

DJ Tognarelli received his B.S. from the University of Richmond where he studied Analytical Chemistry. He is a Chromatography Applications Scientist at JASCO.