New derivatizing reagent for analysis of diethylene glycol by HPLC with fluorescence detection

Abstract

N-(2-Phenyl-indolyl)-acetic acid (PIAA), a new fluorescent derivatizing reagent, was used for the determination of diethylene glycol (DEG) by high-performance liquid chromatography with fluorescence detection. DEG was derivatized to ester by using PIAA in the presence of 1-ethyl-3-(3-dimethylaminopropyl)carbodimide hydrochloride (as dehydrating agent) and 4-(dimethylamino)pyridine (as base catalyst) in acetonitrile at 60 degrees C for 75 min. The influence of solvent, temperature, catalyst base, concentration of labeling reagent, and couple reagent on the derivatization was investigated. The fluorescence detection was performed with excitation at 340 nm and emission at 377 nm. Baseline separation was obtained on an Ultimate XB-C18 analytical column with water/acetonitrile gradient elution, good linearity was obtained within 0.5-50 microg/mL with a correlation coefficient of 0.9997. The limit of detection was 0.01 microg/mL (signal-to-noise ratio = 3). The method has been successfully applied to determine DEG in toothpaste samples with satisfactory recoveries ranging from 89.0 to 94.9%. The proposed method was shown to be a promising technique for the determination of DEG with high sensitivity.

Selective Detection of Diethylene Glycol in Toothpaste Products Using Neutral Desorption Reactive Extractive Electrospray Ionization Tandem Mass Spectrometry

“…No notable morphology change was found in these spiked toothpaste samples, which suggests negligible matrix change caused by adding the DEG solutions into the blank toothpaste samples. Each measurement only took less than 2 s, much faster than those reported in previous literature, − , which is suitable for high-throughput applications. Currently, the hindrance of further speeding up of the measurements is the loading of individual samples, which could be solved by utilizing automatic sampler in the future.…”

“…It has been extremely challenging in analytical science to rapidly and quantitatively detect analytes (such as DEG) incorporated with highly viscous gel mixtures containing nanomaterials, of which toothpaste is a typical representative. Gas chromatography (GC) or its combination with mass spectrometry (GC/MS) has been the best choice available for the determination of DEG in wines and/or human plasma. − More recently, the determination of DEG in pharmaceutical products and toothpastes has been performed using liquid chromatography mass spectrometry (LC/MS). − The methods mentioned above offer satisfactory sensitivity (limit of detection, LOD, as low as 0.005% by weight) and good reproducibility, thus they are regarded as the routine techniques for DEG detection in various matrixes. However, sample preparations such as derivatization procedures required by these methods are normally time-consuming (>40 min) and laborious.…”

“…[9][10][11][12][13] More recently, the determination of DEG in pharmaceutical products and toothpastes has been performed using liquid chromatography mass spectrometry (LC/MS). [14][15][16] The methods mentioned above offer satisfactory sensitivity (limit of detection, LOD, as low as 0.005% by weight) and good reproducibility, thus they are regarded as the routine techniques for DEG detection in various matrixes. However, sample preparations such as derivatization procedures required by these methods are normally time-consuming (>40 min) and laborious.…”