Comprehensive and heart-cutting multidimensional liquid chromatography-mass spectrometry and its applications in food analysis

In food analysis, conventional one-dimensional liquid chromatography methods sometimes lack sufficient separation power due to the complexity and heterogeneity of the analyzed matrices. Therefore, the use of two-dimensional liquid chromatography (2D-LC) turns out to be a powerful tool to consider, especially when coupled to mass spectrometry (MS). This review presents the most remarkable 2D-LC-MS food applications reported in the last 10 years, including a critical discussion of the multiple approaches, modulation strategies as well as the importance of the optimization of the different analytical aspects that will condition the 2D-LC-MS performance. The presence of contaminants in food (food safety), the food quality, and authenticity or the relationship between the beneficial effects of food and human health are some of the fields in which most of the 2D-LC-MS applications are mainly focused. Both heart-cutting and comprehensive applications are described and discussed in this review, highlighting the potential of 2D-LC-MS for the analysis of such complex samples.

Two-dimensional liquid chromatography with reversed phase in both dimensions: A review

Two-dimensional liquid chromatography (2D-LC), and in particular comprehensive two-dimensional liquid chromatography (LC×LC), offers increased peak capacity, resolution and selectivity compared to one-dimensional liquid chromatography. It is commonly accepted that the technique produces the best results when the separation mechanisms in the two dimensions are completely orthogonal; however, the use of similar separation mechanisms in both dimensions has been gaining popularity as it helps avoid difficulties related to mobile phase incompatibility and poor column efficiency. The remarkable advantages of using reversed phase in both dimensions (RPLC×RPLC) over other separation mechanisms made it a promising technique in the separation of complex samples. This review discusses some physical and practical considerations in method development for 2D-LC involving the use of RP in both dimensions. In addition, an extensive overview is presented of different applications that relied on RPLC×RPLC and 2D-LC with reversed phase column combinations to separate components of complex samples in different fields including food analysis, natural product analysis, environmental analysis, proteomics, lipidomics and metabolomics.

Comprehensive and heart-cutting multidimensional liquid chromatography-mass spectrometry and its applications in food analysis

In food analysis, conventional one-dimensional liquid chromatography methods sometimes lack sufficient separation power due to the complexity and heterogeneity of the analysed matrices. Therefore, the use of two-dimensional liquid chromatography (2D-LC) turns out to be a powerful tool to consider, especially when coupled to mass spectrometry (MS). This review presents the most remarkable 2D-LC-MS food applications reported in the last 10 years, including a critical discussion of the multiple approaches, modulation strategies as well as the importance of the optimisation of the different analytical aspects that will condition the 2D-LC-MS performance. The presence of contaminants in food (food safety), the food quality and authenticity or the relationship between the beneficial effects of food and human health are some of the fields in which most of the 2D-LC-MS applications are mainly focused. Both heart-cutting and comprehensive applications are described and discussed in this review, highlighting the potential of 2D-LC-MS for the analysis of such complex samples.

Utilizing online-dual-SPE-LC with HRMS for the simultaneous quantification of amphotericin B, fluconazole, and fluorocytosine in human plasma and cerebrospinal fluid

Amphotericin B (AMB), fluconazole (FZ), and fluorocytosine (FC) are recommended for HIV-associated cryptococcal meningitis (CM) patients as preferred antibiotics. This study presents a fast and automated online-dual-solid phase extraction (SPE)-LC coupled with high resolution mass spectrometer (HRMS) method to simultaneously measure the concentrations of AMB, FZ, and FC in human plasma and cerebrospinal fluid (CSF). Automated sample clean-up was performed on the human plasma and CSF samples with stop-flow heart-cutting two dimensional (2D) separation using a online-dual-SPE system, allowing retention and accumulation of AMB, FZ, and carbamazepine (CBZ, Internal standard (IS)) by the Oasis^®HLB cartridge, and retention and accumulation of FC and 5-methylcytosine hydrochloride (MC, IS) by the HyperSep Hypercarb cartridge respectively. Followed by LC elution, quantification by Q-Exactive Hybrid Quadrupole-Orbitrap with targeted-selected ion monitoring (t-SIM) mode was applied to simultaneously determine the concentrations of AMB, FZ and FC. The bioanalysis was achieved in a total running time of 7min. The method was fully validated according to FDA guidelines. The lowest limit of quantification (LLOQ) was 0.04, 0.04, and 0.40μgmL^-1 for AMB, FZ, and FC, respectively. AMB, FZ, and FC levels were linear in the ranges of 0.04-2.00μgmL^-1, 0.04-2.00μgmL^-1 and 0.40-20.00μgmL^-1, respectively. The method showed good performance for human plasma and CSF samples with linearity (R²>0.99), intra-day and inter-day precision (relative standard deviation, RSD<4.32% and <4.06%, respectively), recovery (89.93-93.28% and 90.09-93.58%, respectively) and matrix effect (96.35-103.78% and 92.32-101.48%, respectively). The validated method was successfully applied in real samples of Chinese patients. Overall, our results indicate that this fully automated, sensitive, and reliable online-dual-SPE-LC-HRMS method is effective for therapeutic drug monitoring (TDM) of AMB, FZ, and FC levels.