A simple, accurate, time-saving and green method for the determination of 15 sulfonamides and metabolites in serum samples by ultra-high performance supercritical fluid chromatography

An accurate and reliable analytical strategy for simultaneous determination of target furanocoumarins and flavonoids in cosmetic and pharmaceutical samples by ultra-high performance supercritical fluid chromatography

Furanocoumarins and flavonoids have various important biological activities and wide application. In the present study, a rapid and reliable supercritical fluid chromatography method was proposed for the separation of 10 target components including 8 furanocoumarins and 2 flavonoids. After detailed condition optimization, the 10 target compounds can be baseline separated on a Trefoil CEL1 (3.0 mm × 150 mm, 2.5 µm) column using gradient elution. A 0.07% (v/v) trifluoroacetic acid in ethanol was determined to be the most proper mobile phase for the separation of target compounds. The column temperature, back pressure, flow rate were set at 36 ℃, 2000 psi, 1.0 mL min^-1 to 1.4 mL min^-1, respectively. The ten target compounds were analyzed within 24 min using the optimized conditions. Under the optimized conditions, all the target compounds showed good linearity with linear correlation coefficients higher than 0.995, and satisfactory recovery in the range of 83.52-112.92%. All these results showed that the developed ultra-high performance supercritical fluid chromatography method was reliable and effective. Finally, the application of the developed method to cosmetic, Psoraleae fructus and Angelicae dahuricae radix samples were presented. The results highlight the applicability of the ultra-high performance supercritical fluid chromatography method to the analysis of interested compounds in pharmaceutical and cosmetic samples.

An alternative strategy based on ultra-high-performance supercritical fluid chromatography for full monosaccharide compositional analysis of polysaccharides in Schisandra chinensis fruits

Due to green and environment-friendly characteristics, ultra-high-performance supercritical fluid chromatography has been widely used in analytical fields in recent years, but until now few reports are available for monosaccharide compositional analysis of macromolecule polysaccharides. In this study, an ultra-high-performance supercritical fluid chromatography technology with an unusual binary modifier is used to determine the monosaccharide compositions of natural polysaccharides. Each carbohydrate herein is simultaneously labeled as 1-pheny-3-methyl-5-pyrazolone and acetyl-derivative via pre-column derivatizations aiming to increase UV absorption sensitivity and decrease water solubility. Ten common monosaccharides are fully separated and detected on ultra-high-performance supercritical fluid chromatography combined with a photo-diode array detector by systematic optimization of multiple relevant parameters, for example, column stationary phases, organic modifiers, additives, flow rates, and so on. Compared with carbon dioxide as a mobile phase, the addition of a binary modifier increases the resolution of analytes. Additionally, this method has the advantages of small consumption of organic solvent, safety, and being environmental-friendly. It has been successfully applied for full monosaccharide compositional analysis of heteropolysaccharides from Schisandra chinensis fruits. To sum up, a new alternative approach is provided for monosaccharide compositional analysis of natural polysaccharides.

Development of a high-throughput method for the comprehensive lipid analysis in milk using ultra-high performance supercritical fluid chromatography combined with quadrupole time-of-flight mass spectrometry

Milk lipids are one of the most complex materials in nature and are associated with many physiological functions, hence it is important to comprehensively characterize lipids profiles to evaluate the nutritional value of milk. A quick method was developed by ultra-high performance supercritical fluid chromatography coupled to electrospray ionization quadrupole time-of-flight mass spectrometry (UHPSFC-ESI-QTOF-MS) to analyze the non-polar and polar lipids profiles of cow, goat, buffalo, human milk, and infant formulas in 7 min. All chromatographic conditions were carefully optimized and their effect on the chromatographic behavior of lipid classes and species was discussed. Under optimized conditions, 12 lipid classes (triacylglycerols, diacylglycerols, monoglyceride, fatty acids, phosphatidylcholine, phosphatidylethanolamine, phosphatidylinositol, phosphatidylserine, phosphatidylglycerol, sphingomyelin, lyso-phosphatidylcholine, and lyso-phosphatidylethanolamine) were separated and each class was further separated in single analysis to facilitate the identification. 250 lipid species in real samples were characterized and quantified. This result demonstrates the applicability of the UHPSFC-ESI-QTOF-MS method in the high-throughput and comprehensive lipid analysis of milk, and will hopefully help to provide nutritionists with the lipid distribution in different types of milk, as well as help in the design of more suitable infant formula for babies.

Determination of Tetracycline Using Ultrasound-Assisted Dispersive Liquid-Liquid Microextraction Based on Solidification of Floating Organic Droplet Followed by HPLC-UV System

BACKGROUND

Tetracyclines (TCs) are a group of broad-spectrum antibiotics that may be used to control bacterial diseases in humans or are applied as feed additives to enhance growth in farm animals. TCs are released into the aquatic environment via different pathways. Many analytical methods combined with a preconcentration step have been introduced for the determination of TC in various environmental samples.

OBJECTIVE

The objective this paper is developing reliable analytical methods for determination of TC trace in various environmental samples.

METHOD

In the present work, combined ultrasound-assisted and dispersive liquid-liquid microextraction according to the solidification of floating organic drop as a sample preconcentration procedure for determining TC hydrochloride HPLC in water and serum samples was used.

RESULTS

A series of parameters, including the type and volume of disperser and extraction solvents, salt effect, extraction time, and pH of solution influencing the extraction efficiency of UA-DLLME-SFO was examined. Enrichment factors were in the range of 125-137 for TC hydrochloride under optimum conditions. The linear range was calculated from 0.005 to 3 mg/L and LOD at 0.002 mg/L. RSDs were in the range of 2.7 to 3.2 (n = 5). The UA-DLLME-SFO method used in water and serum samples revealed good extraction recoveries with RSD of 2.7-4.3%.

CONCLUSIONS

This method significantly decreased the organic solvent volume from 3 mL to 90 µL, also LOD and linear ranges were lower than or almost close to levels obtained in other research studies. In this procedure, an ultrasound bath enhanced the mixing and contact between the sample solution and the extraction solvent.

MoS2-Assisted LDI Mass Spectrometry for the Detection of Small Molecules and Quantitative Analysis of Sulfonamides in Serum

A two-dimensional MoS₂ nanosheet was prepared by a chemical exfoliation method and served as an excellent matrix for the detection of small molecules by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). In comparison with organic matrices (CHCA, 3-AQ) and a graphene matrix, we found that a MoS₂ matrix showed better performance in analysis of amino acids, peptides, fatty acids, and sulfonamides. A systematic comparison of the MoS₂ matrix with both ion modes showed that mass spectra produced in negative ion mode featured a corresponding single deprotonated ion, which was rather different from the complex multiple alkali metal addition peaks present in positive ion mode. In addition, better sensitivity and reproducibility were obtained in negative ion mode. The ionization mechanism of MoS₂ as a matrix in negative ion mode was further discussed. The deproton peak intensity of the analyte fatty acid decreased after the addition of the hole-scavenger KSCN, indicating that the ionization of the fatty acid was caused by the Auger complex effect of MoS₂ and electron injection. Experiments have shown that the MoS₂ matrix detects small molecules with good repeatability and can perform semiquantitative analysis of sulfonamides. Finally, the MoS₂ matrix was employed for quantitative determination of sulfamethoxine in serum samples by an internal standard method. This MoS₂-assisted laser desorption/ionization mass spectrometry (MoS₂-assisted LDI MS) method provides a simple, rapid, high-throughput approach to evaluate the drug levels in the patient serum and can achieve convenient drug therapy monitoring.

Magnetic solid-phase extraction based on carbon nanotubes for determination of sulfamethoxazole, acetyl sulfamethoxazole and aditoprim residues in edible swine tissues with liquid chromatography tandem mass spectrometry

Sulphonamides (SAs) are widely used in animal husbandry. In our work, based on multi-walled carbon nanotubes, a novel residue method was developed for highly sensitive and determination trace levels of sulfamethoxazole, acetyl sulfamethoxazole and aditoprim in edible swine tissues by LC-MS/MS with magnetic solid-phase extraction. The samples were extracted using 2% ammoniated acetonitrile and purified by magnetic solid phase extraction (MSPE). Under the optimal conditions, good linearity was obtained ranging from 5 to 160 μg kg^-1. The limits of detection (LOD) and quantification (LOQ) were 2 μg kg^-1 and 5 μg kg^-1 respectively. The average recoveries were 73.9-94.8% at different spiking levels. The inter-day RSDs were 6.2-10.7% and the intra-day RSDs were 2.4-5.4%. MSPE based on multi-walled carbon nanotubes was a simple and efficient method to enrich and separate the analyses and could be successfully applied for extraction of sulfamethoxazole, acetyl sulfamethoxazole and aditoprim residues in swine tissues.

Study of the Fragmentation Pathways of Sulfonamides by High-resolution Mass Spectrometry: Application to their Detection in Plasma by Direct Infusion

Background:

The high resolving and accuracy power of the HRMS instrument enabled us to identify the product ions and to propose detailed fragmentation pathways and diagnostic fragment ions.

Methods:

In the present work, the fragmentation pathways of five sulfonamides antibiotics, namely sulfamerazine, sulfathiazole, sulfadiazine, sulfadimethoxine and sulfamethoxazole, by High-Resolution Mass Spectrometry (HRMS) are presented. The HRMS spectra were recorded with a Q-TOF (Time of Flight) spectrometer with Electrospray Ionization (ESI) in both negative and positive mode.

Results:

Specific characteristic ions for each one of the sulfonamide antibiotics under positive ESI mode are proposed for the first time. Fragment ions of this particular class of analytes may be used to rapidly identify compounds with common structural features.

Conclusion:

The direct infusion of plasma samples, avoiding any prior chromatographic steps, to identify the existence of sulfonamide antibiotics is demonstrated herein.

Determination of 14 heterocyclic aromatic amines in meat products using solid-phase extraction and supercritical fluid chromatography coupled to triple quadrupole mass spectrometry

A novel, simple, and sensitive method has been developed for simultaneous determination of 14 heterocyclic aromatic amines in meat product using solid-phase extraction combined with ultrahigh-performance supercritical fluid chromatography coupled to tandem quadrupole mass spectrometry. The analytes could be separated within 7 min and identified using their retention times and mass. The developed method was validated based on the linearity, limits of quantification, precision, and accuracy. The recovery ranged from 52.3 to 97.5% with an acceptable standard deviation, which is not higher than 6%. The limits of quantitation ranged from 0.03 to 0.17 µg/kg. The selectivity and sensitivity were satisfactory in multiple reaction monitoring mode. The method was applied to commercial meat products, and the results demonstrated that the novel method has potential for the analysis of the targets in food matrices. This is the first work reporting the simultaneous quantification of 14 heterocyclic aromatic amines by means of ultrahigh-performance supercritical fluid chromatography coupled to tandem quadrupole mass spectrometry.

Current state of bioanalytical chromatography in clinical analysis

Chromatographic methods have become popular in clinical analysis in both routine and research laboratories.

Supercritical fluid chromatography: a promising alternative to current bioanalytical techniques

During the last years, chemistry was involved in the worldwide effort toward environmental problems leading to the birth of green chemistry. In this context, green analytical tools were developed as modern Supercritical Fluid Chromatography in the field of separative techniques. This chromatographic technique knew resurgence a few years ago, thanks to its high efficiency, fastness and robustness of new generation equipment. These advantages and its easy hyphenation to MS fulfill the requirements of bioanalysis regarding separation capacity and high throughput. In the present paper, the technical aspects focused on bioanalysis specifications will be detailed followed by a critical review of bioanalytical supercritical fluid chromatography methods published in the literature.

Development and application of sub-2-μm particle CO2 -based chromatography coupled to mass spectrometry for comprehensive analysis of lipids in cottonseed extracts

RATIONALE

Refined cottonseed oil has widespread applications in the food and chemical industries. Although the major lipids comprising cottonseed oil (triacylglycerols) are well known, there are many diverse lipid species in cotton seeds that occur at much lower levels and have important nutritional or anti-nutritional properties.

METHODS

The lipid technical samples were prepared in chloroform. The biological samples were extracted using a mixture of isopropanol/chloroform/H₂ O (2:1:0.45). The data were collected using high and low collision energy with simultaneous data collection on a time-of-flight (TOF) mass spectrometer which allowed the characterization of lipids by precursor and product ion alignment. The supercritical fluid chromatography methodology is flexible and can be altered to provide greater retention and separation. The comprehensive method was used to screen seed lipid extracts from several cotton genotypes using multivariate statistical analysis.

RESULTS

Method variables influencing the peak integrity and chromatographic separation for a mixture of lipids with different degrees of polarity were explored. The experiments were designed to understand the chromatographic behavior of lipids in a controlled setting using a variety of lipid extracts. Influences of acyl chain length and numbers of double bonds were investigated using single moiety standards.

CONCLUSIONS

The methodology parameters were examined using single moiety lipid standards and standard mixtures. The method conditions were applied to biological lipid extracts, and adjustments were investigated to manipulate the chromatography. Insights from these method variable manipulations will help to frame the development of targeted lipid profiling and screening protocols. Copyright © 2017 John Wiley & Sons, Ltd.

Upconversion Nanoparticles and Monodispersed Magnetic Polystyrene Microsphere Based Fluorescence Immunoassay for the Detection of Sulfaquinoxaline in Animal-Derived Foods

A novel fluorescence immunoassay for detecting sulfaquinoxaline (SQX) in animal-derived foods was developed using NaYF4:Yb/Tm upconversion nanoparticles (UCNPs) conjugated with antibodies as fluorescence signal probes, and monodisperse magnetic polystyrene microspheres (MMPMs) modified with coating antigen as immune-sensing capture probes for trapping and separating the signal probes. Based on a competitive immunoassay format, the detection limit of the proposed method for detecting SQX was 0.1 μg L(-1) in buffer and 0.5 μg kg(-1) in food samples. The recoveries of SQX in spiked samples ranged from 69.80 to 133.00%, with coefficients of variation of 0.24-25.06%. The extraction procedure was fast, simple, and environmentally friendly, requiring no organic solvents. In particular, milk samples can be analyzed directly after simple dilution. This method has appealing properties, such as sensitive fluorescence response, a simple and fast extraction procedure, and environmental friendliness, and could be applied to detecting SQX in animal-derived foods.