Determination of long-chain fatty acids in anaerobic digester supernatant and olive mill wastewater exploiting an in-syringe dispersive liquid-liquid microextraction and derivatization-free GC-MS method

Sustainable valorization of slaughterhouse waste through anaerobic digestion: A circular economy perspective

Slaughterhouse waste (SHW) poses significant environmental challenges due to its complex composition. In response, a novel review exploration of anaerobic digestion (AD) as a means of valorising SHW within the context of the circular economy (CE) is presented. The physicochemical properties of individual SHW, representing key parameters for the correct management of the AD process, are scrutinized. These parameters are further connected with identifying suitable pretreatment methods to enhance biogas production. Subsequently, the review examines the diverse technologies employed in the AD of SHW, considering the complexities of mono- or co-digestion. Various AD systems are evaluated for their effectiveness in harnessing the substantial biogas production potential from SHW, encompassing key parameters, reactor configurations, and operational conditions that influence the AD process. Moreover, the review interestingly extends its scope to the recovery and management of digestate, the by-product of AD. Along with the digestate composition, strategies for various utilization of this by-product are discussed. This investigation thus underscores, within the principles of the CE, the dual sustainable benefits of SHW processing via AD in biogas production and utilization of the resultant nutrient-rich digestate in various sectors.

Development of a 3-step sequential extraction method to investigate the fraction and affecting factors of 21 antibiotics in soils

Antibiotic exist in various states after entering agricultural soil through the application of manure, including the aqueous state (I), which can be directly absorbed by plants, and the auxiliary organic extraction state (III), which is closely associated with the pseudo-permanence of antibiotics. However, effective analytical methods for extracting and affecting factors on fractions of different antibiotic states remain unclear. In this study, KCl, acetonitrile/Na2EDTA-McIlvaine buffer, and acetonitrile/water were successively used to extract states I, II, and III of 21 antibiotics in soil, and the recovery efficiency met the quantitative requirements. Random forest classification and variance partitioning analysis revealed that dissolved organic matter, pH, and organic matter were important factors affecting the recovery efficiency of antibiotic in states I, II, and III, respectively. Additionally, 65-day spiked soil experiments combined with Mantel test analysis suggested that pH, organic acids, heavy metals, and noncrystalline minerals differentially affected antibiotic type and state. Importantly, a structural equation model indicated that organic acids play a crucial role in the fraction of antibiotic states. Overall, this study reveals the factors influencing the fraction of different antibiotic states in soil, which is helpful for accurately assessing their ecological risk.

Sample preparation for fatty acid analysis in biological samples with mass spectrometry-based strategies

Fatty acids (FAs) have attracted many interests for their pivotal roles in many biological processes. Imbalance of FAs is related to a variety of diseases, which makes the measurement of them important in biological samples. Over the past two decades, mass spectrometry (MS) has become an indispensable technique for the analysis of FAs owing to its high sensitivity and precision. Due to complex matrix effect of biological samples and inherent poor ionization efficiency of FAs in MS, sample preparation including extraction and chemical derivatization prior to analysis are often employed. Here, we describe an updated overview of FA extraction techniques, as well as representative derivatization methods utilized in different MS platforms including gas chromatography-MS, liquid chromatography-MS, and mass spectrometry imaging based on different chain lengths of FAs. Derivatization strategies for the identification of double bond location in unsaturated FAs are also summarized and highlighted. The advantages, disadvantages, and prospects of these methods are compared and discussed. This review provides the development and valuable information for sample pretreatment approaches and qualitative and quantitative analysis of interested FAs using different MS-based platforms in complex biological matrices. Finally, the challenges of FA analysis are summarized and the future perspectives are prospected.

Comprehensive lipid hydrolysis observation in anaerobic digestion

Lipid hydrolysis monitoring, including especially glycerides, is necessary for comprehending the anaerobic digestion process in lipid-rich substrates processing. This reaction has not been investigated in such detail so far, despite its potential to be crucial in assuring a stable process. This study suggested and thoroughly validated an uncomplicated method of monitoring lipid hydrolysis during anaerobic digestion, achieving recovery values >95 % with an average relative standard deviation <5 %. Subsequently, the method was applied on the very first detailed observation of glyceride hydrolysis in the anaerobic sludge, tracking even changes in fatty acid profiles during anaerobic digestion. Results showed that lipid hydrolysis can take several days, thus likely affecting the whole anaerobic digestion of lipids. The method aims to provide answers to improve understanding of lipids' fate and their inhibition phenomena in anaerobic digestion.

A green QuEChERS syringe filter based micro-solid phase extraction using hydrophobic natural deep eutectic solvent as immobilized sorbent for simultaneous analysis of five anti-diabetic drugs by HPLC-UV

BACKGROUND

Here, it has been discussed about creating a specific and sustainable analytical technique for monitoring anti-diabetic drugs in order to accurately determine the dosage in patients and reduce side effects, remove them from wastewater (as emerging contaminants), and ultimately abate pharmaceutical pollutants in the environment.

RESULTS

In this research, a green and reproducible Quick Easy Cheap Effective Rugged Safe (QuEChERS) method based on syringe filter based micro-solid phase extraction (SF-μSPE) coupled with HPLC-UV using a green sorbent was developed and optimized for the extraction of five anti-diabetic drugs from wastewater, serum, and plasma real samples. A novel green sorbent composed of a liquid mixture of thymol: menthol ([Thy]:[Men], 1:1) hydrophobic natural deep eutectic solvent (HNADES) and curcumin (Cur) immobilized into the non-toxic and biodegradable polyvinyl alcohol (PVA) electrospun nanofibers' mat was synthesized simply via cheap equipment. Cur was added to enhance the hydrophobicity and functionality of the sorbent. The immobilization process was performed by soaking the mat in the liquid mixture for a specific duration. The correct synthesis and experimental molar ratio of the HNADES components were confirmed by ATR-FTIR and NMR (1H and 13C) spectroscopy. The prepared green sorbent (Cur-HNADES/PVA) was characterized using ATR-FTIR, FE-SEM, EDX/EDX mapping analysis, and water contact angle (WCA) measurement, and it exhibited satisfactory adsorption capacity for the target analytes.

SIGNIFICANCE

Under optimal conditions (pH = 6.0, adsorption cycle = 3, sample volume = 5.0 mL, desorption cycle = 1, type and volume of elution = 80:20 %v/v MeOH/ACN and 500.0 μL), the method was validated in terms of specificity, linear dynamic ranges (LDRs = 0.1-2000.0 μg L-1 and 0.1-1800.0 μg L-1), limits of detection (LODs = 0.03-0.09 μg L-1), and precision (within-day RSDs% = 0.32-1.45% and between-day RSDs% = 0.59-2.03%). Evaluation of the greenness aspects of the proposed method was accomplished using the Green Analytical Procedure Index (GAPI) and Analytical GREEnness (AGREE) approaches. It is noteworthy that the conducted research represents the first report of the synthesis and application of this novel and green sorbent for the determination of anti-diabetic drugs in the mentioned real samples.

Simultaneous determination of 22 fatty acids in total parenteral nutrition (TPN) components by gas chromatography-mass spectrometry (GC-MS)

Evaluating total parenteral nutrition (TPN) products for quality assurance and quality control is crucial due to the chemical complexity of its components. With the advent of exploring different approaches for analysing TPN components using tandem mass spectrometry techniques, there is still a need for a robust and reproducible method for industrial routine analyses. This study allows simple, simultaneous determination of 22 fatty acids (FAs) commonly found in TPN components using gas chromatography-mass spectrometry (GC-MS). Five different transesterification techniques were applied for the FA standards and the sodium methoxide in methanol-dimethyl carbonate method was selected due to its good methylation efficiency. Fatty acid methyl esters (FAMEs) were separated in gas chromatography using an HP-5MS UI column with helium as the carrier gas. Mass spectrometry was used to fragment and quantify FAMEs using electron ionization (EI) and selected ion monitoring (SIM) mode. The analytical method was evaluated using the guidelines from the US Food and Drug Agency (FDA) and European Medicines Agency (EMA) in compliance with the International Council for Harmonization (ICH) document Q2(R2). Correlation coefficients (R²) of the calibration curves for FAMEs were 0.99, except for C24:1 n-9 and C24:0, both R² = 0.98. The limits of detection (LOD) and quantification (LOQ) were found to be 1.69 μg mL^-1 and 5.14 μg mL^-1, respectively. The linear range was from 3.10-179.9 μg mL^-1 for most FAMEs, except for C18:1 n-7 (3.96-224.9 μg mL^-1) and C18:1 n-9 (6.30-349.57 μg mL^-1). The intra-day and inter-day precision coefficients of variance (CV) of the method were less than 11.10% and 11.30%, respectively. Freeze-thaw cycles and ambient temperature measurements were performed for assessing sample stability. The validated method was applied to analyse major TPN components-fish and olive oils, and an unidentified lipid sample. The presented GC-MS method is simple and robust in the identification and quantification of 22 fatty acids simultaneously in the tested TPN components.

Lab-in-Syringe, a Useful Technique for the Analysis and Detection of Pollutants of Emerging Concern in Environmental and Food Samples

Lab-in-syringe is a new approach for the integration of various analytical extraction steps inside a syringe. Fully automated dispersive liquid-liquid microextraction is carried out in-syringe using a very simple instrumental setup. Dispersion is achieved by aspiration of the organic phase and then the watery phase into the syringe as rapidly as possible. After aggregation of the solvent droplets, the organic phase is pushed towards the detector allowing a highly sensitive spectrophotometric or fluorimetric detection. This technique is very useful not only for the preconcentration of analyte, but also for the elimination of their interferences. In this work, its application is described using solvents that are lighter and denser than water. The magnetically assisted variant and its coupling to different instruments has been also described with the aim of increasing the resolution of complex samples, especially useful for the determination of emerging contaminants.

One-step fabrication of COF-coated melamine sponge for in-syringe solid-phase extraction of active ingredients from traditional Chinese medicine in serum samples

In this study, a covalent organic framework (COF)-TpBD-supported melamine sponge (MS) was fabricated through a one-step hydrothermal method. The obtained monolithic column was then applied in in-syringe solid-phase extraction (IS-SPE) for the separation of three volatile ingredients from serum samples. Given credit for the superior adsorption capacity of the COF and the homogeneous microporous property of MS, the developed column exhibited satisfactory separation of the targets. And the dominating adsorption mechanism was the hydrophobic interaction forces between TpBD and targets and the high mass transfer efficiency provided by the large pore structure of MS. The results of dynamic adsorption showed that the MS@TpBD column displayed much better adsorption performance than blank MS and TpBD. And it has featured great reusability up to 5 cycles and obtained satisfied recovery values (87.9 ~ 110.3%) in serum samples. As a result of sample clean-up, this column offers low limit of detections (LODs) down to 0.014, 0.010, and 0.020 μg/mL, respectively. In summary, we believe that this convenient separation column has prominent application promise in the fields of separating activity ingredients in biological samples.