An overview of multidimensional liquid phase separations in food analysis

Abstract

Food safety is a priority public health concern that demands analytical methods capable to detect low concentration level of contaminants (e.g. pesticides and antibiotics) in different food matrices. Due to the high complexity of these matrices, a sample preparation step is in most cases mandatory to achieve satisfactory results being usually tedious, lengthy, and prone to the introduction of errors. For this reason, many research groups have focused efforts on the development of online systems capable to do the cleanup, concentration, and separation steps at once through multidimensional separation techniques (MDS). Among several possible setups, the most popular are the multidimensional chromatographic techniques (MDC) that consist in combining more than one mobile and/or stationary phase to provide a satisfactory separation. In the present review, we selected a variety of multidimensional separation systems used for food contaminant analysis in order to discuss the instrumentation aspects, the concept of orthogonality, column approaches used in these systems, and new materials that can be used in these columns. Selected classes of contaminants present in food matrices are introduced and discussed as example of the potential applications of multidimensional liquid phase separation techniques in food safety.

Innovative process methodologies for the agro-food sector: reorganization of technical processes to acquire new skills

“…The reasons that have led the research team to consider the above critical issues arise from the observation, in recent years, of organizational difficulties, problems in quality control, possible delays in response times to customers and, as a result, in the potential loss of customers as well as the lack of opportunity to provide innovative services to each type of customer. Multi-residual analysis is aimed at identifying residual substances on products intended for food in the form of any matrix: solid, liquid or gaseous [6][7][8]. They are particularly requested and widespread on products of vegetable, animal and water origin.…”

Recent trends in sorption‐based sample preparation and liquid chromatography techniques for food analysis

“…Because of the usual complex composition of food, which contains many endogenous compounds, off‐line techniques are not always efficient enough to monitoring the compounds of interest . Therefore, on‐line multidimensional LC has emerged to overcome this problem.…”

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

“…In which part of the system the sample preparation and in which one the chromatographic separation steps really happen? Which are the required characteristics of the extraction device utilized for the first step and very often also termed “extraction column” ?…”

“…One reason for this is the high number of terms and symbols used for approaches with similar characteristics (e.g. on‐line SPE‐chromatography, column switching, valve switching techniques, multidimensional separation, in‐tube SPME, turbulent flow chromatography (TFC), and so on) that differs from each other by small details on the devices used . In addition to that, there are a number of other approaches that allow the on‐line sample preparation being carried out without the need of an additional “interface” to transfer part of the sample from the sample preparation technique to the chromatographic system, as occur in the previously cited cases.…”

“…valveless, valve, or modulator) that transfers the processed sample from the sample preparation step (first dimension) to a chromatographic system (second dimension). This set up is generally termed multidimensional separation system . The term multidimensional separation systems admit two or more separation steps; in practice, only two steps are usually employed and in this case the more common term for this is bidimensional due the use of only two separations dimensions.…”