Introduction

Preservatives are a common additive used in improving food shelf-life. Preservatives are used to prevent microbial growth which can lead to putrefaction and rancidification of foodstuffs. Many of the preservatives used in commercial manufacturing a certain level of toxicity and their use is strictly controlled by regulatory agencies such as the FDA. In this application note, the analysis of one of the most commonly used food preservatives p-Hydroxybenzoate Ester was made according to the food additive test method described in the Methods of Analysis in Health Science as reported below.

LC-4000 HPLC system

Experimental

Chromatographic conditions
Column:  CrestPak C18S (4.6 mmI.D. x 150 mmL, 5 µm)
Eluent:  Acetonitrile/5 mmol/L Citrate buffer (pH 4.1) (60/40)
Flow rate:   1.0 mL/min
Column temp.:   40 ºC
Wavelength:  270 nm
Injection volume:  10 µL
Standard sample:  p-Hydroxybenzoate ester 1 µg/mL each in water (methyl, ethyl, propyl, butyl, isobutyl)

Structural formulae of p-Hydroxybenzoate Ester are as follows (Figure 1).

Figure 1. Structural Formulae of p-Hydroxybenzoate Esters

Keywords

Food additive, Preservative, p-Hydroxybenzoate Esters, C18 column, UV detector, HPLC, isocratic separation

Results

The chromatogram of a standard mixture of p-Hydroxybenzoate Esters is shown in Figure 2. Five components were eluted with good resolution in under 10 minutes using an isocratic method.

Figure 2. Chromatogram of the Standard Mixture of p-Hydroxybenzoate Ester