Online desorption of molecularly imprinted stir bar sorptive extraction coupled to high performance liquid chromatography for the trace analysis of triazines in rice

Abstract

Based on a special homemade interface, the molecularly imprinted stir bar sorptive extraction was coupled to high performance liquid chromatography for the online desorption and analysis. During desorption, the analytes desorbed from stir bar were delivered to a sample loop and then was introduced into liquid chromatography for further analysis. The online desorption and introduction processes were real-time monitored by the ultraviolet detector of the liquid chromatography system. In this way, the method sensitivity and reproducibility was improved for the introduction timing of the desorption solvent with greatest concentration of the target analytes was accurately controlled. To demonstrate the feasibility of the method, terbuthylazine imprinted stir bar was synthesized and used for the analysis of nine triazines in rice. Under the optimized conditions, limits of detection of 0.02-0.11 μg/L and precision within 4.3-7.2% were achieved. The new method was compared with other two traditional offline desorption procedures, i.e. ultrasonic-assisted desorption and static thermal desorption. The comparison results showed that the proposed method is accurate, precise, fast, and suitable for the trace analysis of complex samples.

On‐line approaches for the determination of residues and contaminants in complex samples

“…The authors achieved a LOQ of 0.005 μg/L, which is 20 times lower than that obtained by Zhong et al. , even considering that Zhong utilized a heart‐cut technique to improve the method sensibility. This can be attributed to two factor: usually a GC system has smaller noise than LC system and also the use of a thermal desorption that do not dilute the analytes as in case of a liquid desorption commonly utilized with LC.…”

“…The SPME systems presented here with liquid desorption has more characteristics of on‐line as the SBSE system proposed by Zhong et al. . The systems commercially available for SBSE from Gerstel (Twister TM , TBU, TBS, and TBU) as well as the MEPS system (called on‐line) have the presence of an robotic performing some steps of the extraction; according to Puig this configures an at‐line system.…”

Recent Advances in Extraction and Stirring Integrated Techniques

“…In the last few years, this workflow has been proposed for the extraction of triazines in rice [9], thiabendazole in citrus samples [10], and melamine in powdered milk [11]. The selectivity of MIPs restricts their applicability to compounds with similar chemical structures.…”

Determination of melamine in powdered milk by molecularly imprinted stir bar sorptive extraction coupled with HPLC

“…It shows not only high selectivity, but also large extract capacity and rapid equilibrium. In this regard, molecularly imprinted stir bar (MIP-SB) has been applied to the fields of environment and health monitoring [19][20][21][22][23][24]. Up till now, there has been no report about using MIP-SB to determine MA.…”