High-salt Samples Research Articles

Microsyringe-based slug-flow microextraction for rapid and accurate determination of antibiotics in highly saline seawater

BackgroundExtensive use of antibiotics leads to widespread environmental pollution, endangering ecosystems, and human health. It is particularly concerning, posing global threats requiring urgent attention and action. In this regard, the shift to mass spectrometry in determining antibiotics is highly desirable. Significant progress has been made in analyzing and optimizing the sensitivity of high-salt samples. However, the persistence of cumbersome operational procedures presents a significant challenge to this shift. Thus, the persistence of complex operational procedures needs to be addressed. ResultsIn this study, a rapid and direct method for determining antibiotics in highly saline environmental water samples using microsyringe-based slug-flow microextraction (MSFME)-droplet spray ionization (DSI) mass spectrometry (MS) has been described. The proposed method successfully detected clarithromycin, ofloxacin, and sulfadimidine in seawater within a linear range of 1–1200 ng mL−1, with low limits of detection of 0.19 ng mL−1, 0.17 ng mL−1, and 0.20 ng mL−1, respectively (Signal/Noise = 3). Additionally, spiked real seawater samples of all three antibiotics demonstrated satisfactory recoveries (95.1–107.5%) and precision (RSD≤8.8%). The MSFME–treated high-salt sample (3.5 wt%) showed a mass spectral response intensity 4–5 orders of magnitude higher than the untreated medium-salt sample (0.35 wt%). Furthermore, exploration of the applicability of MSFME showed that it is suitable not only for high-salinity (3.5 wt%) samples but also for salt-free or low-salt and hard water samples rich in calcium and magnesium ions. SignificanceComparisons with other methods, complex laboratory setups for sample processing are now simplified to a single step, completing the entire process, including desalination and detection, MSFME–DSI–MS provides faster results in less than 1 min while maintaining sensitivity comparable to that of other detection methods. In conclusion, this advancement provides an exceptionally simplified protocol for the rapid, highly sensitive, and quantitative determination of antibiotics in environmental water samples.

Impact of NaCl on physicochemical properties, microbial community, and pathogen surveillance in the Chinese traditional fermented broad bean (Vicia faba L.) paste

Doubanjiang (DBJ), a mixed fermented broad bean (Vicia faba L.) and red pepper (Capsicum annuum L.) condiment used worldwide, is known for its high-salt content (∼20g/100g). Industry demands sodium reduction in DBJs. In this study, we investigated the physicochemical properties, microbial community changes, and pathogen surveillance in DBJ samples with varying salt contents (10g/100g, 15g/100g, 20g/100g and 25g/100g). Our findings revealed that these samples could be categorized into two groups: low-salt (10g/100g) and high-salt samples (15–25g/100g). In low-salt samples, Lactobacillus emerged as the predominant bacteria, exhibiting higher antioxidant activity. The most concentrated organic acids were γ-aminobutyric acid and lactic acid. Conversely, Staphylococcus dominated the bacteria composition in high-salt samples. Human pathogenicity such as Proteus mirabilis, Escherichia coli, and Klebsiella pneumoniae were discovered in both low- and high-salt samples. Higher abundance of antimicrobial resistances was observed in high-salt samples while slightly increased biogenic amine content in low-salt samples. This knowledge provides insights into impact of NaCl on fermented broad bean (Vicia faba L.) paste.

ICP-MS Configuration and Optimization for Successful Routine Analysis of Undiluted Seawater

Inductively coupled plasma–mass spectrometry (ICP-MS) is a technique increasingly being used in commercial laboratories and industries that analyze samples with complex matrices, such as seawater, wastewater, saline groundwater, and other high salt samples. These laboratories often choose ICP-MS for its fast, multielement capability and high sample throughput, but time and cost pressures mean that laboratories have little time for sample preparation and method development. The time and cost pressures can lead to performance and operational issues because an ICP-MS instrument optimized for the highest sensitivity may not have the sufficient matrix tolerance to analyze high salt samples. In this article, we describe a method to optimize plasma robustness and interference control that enables a modern ICP-MS to perform simple, accurate, and routine analysis of critical trace elements in undiluted seawater.

4D-Printed Temperature-Controlled Flow-Actuated Solid-Phase Extraction Devices.

Four-dimensional printing (4DP) technologies can extend the functionality and applicability of manufactured analytical devices through employing stimuli-responsive materials. In this study, we used a photocurable resin of stimuli-responsive shape-memory polymers and digital light processing three-dimensional printing (3DP) to fabricate a smart sample pretreatment device featuring a solid-phase extraction (SPE) column and a temperature-controlled flow-actuated valve. Through manipulation of the temperatures and flow rates of the sample, eluent, and rinsing streams, we used this 4D-printed SPE device to extract Mn, Co, Ni, Cu, Zn, Cd, and Pb ions from high-salt content samples and remove the sample matrix prior to their determination by inductively coupled plasma mass spectrometry. After optimizing the valve design and operation and the analytical scheme, this device displayed competitive analytical performance-the method detection limits (MDLs) ranged from 0.7 to 22.1 ng L-1 for these metal ions (the MDLs ranged from 0.5 to 18.8 ng L-1 when validating the same printed SPE column using an online automatic system equipped with electric switching valves). Furthermore, we performed analyses of these metal ions in three reference materials (CASS-4, 1643f, and 2670a) and spike analyses of collected samples (seawater, ground water, river water, and human urine) to confirm the reliability and applicability of this analytical method. For the first time, 4DP has been used to fabricate a multi-functional, stimuli-responsive sample pretreatment device displaying analytical performance equal to that of a commercial apparatus. This novel approach builds upon the functionality and diversity of 3DP-enabling devices with the goal of developing more efficient analytical schemes.

Direct Analysis of Proteins in Physiological Samples with Three-Dimensional Paper-Based Isoelectric Focusing

Point-of-care testing (POCT) of proteins is crucial for on-site and rapid diagnosis of diseases in community and family medicine. Microfluidic paper-based analytical devices (µPADs) have attracted growing attention in POCT of proteins, while the practical applications of µPADs in the analysis of proteins in physiological samples is still limited as physiological samples are usually high-salt and complex. Herein, we developed a three-dimensional (3D) paper-based isoelectric focusing (IEF) platform, which is composed of power supply, reservoirs and separation channel make by origami and stacking of cellulose acetate membrane, to simultaneously separate and enrich proteins in both low-salt samples and high-salt samples, especially for directly pretreating and analyzing proteins in physiological samples. Under the optimized experimental conditions, standard proteins (Phy and BHb) were separated in 18 min under a 36.0 V power supply and obtained 10-fold enrichment using the 3D paper-based IEF platform. Then, the capability of the 3D paper-based IEF platform with using a 12.0 V battery as power supply for direct pre-treatment of high-salt samples was proven through separating three standard proteins in saline (0.9 % NaCl) with separation resolution (SR) >1.29. Through further coupling with colorimetric and lateral flow strip measurements, the 3D paper-based IEF platform was applied to directly pre-treat and quantitatively analyze the two disease biomarkers, i.e., microalbuminuria and C-reactive proteins in clinical human serum. The analytical results had the relative deviations of <8.4% and <13.1% to clinical results, respectively. As the first report of the paper-based IEF platform for directly pretreating high-salt samples, this work proposes a new strategy to minimize the difficulty of directly processing high-salt samples with traditional IEF system and provides a versatile, miniaturized and low voltage demand analytical platform for POCT of proteins in physiological samples.

A Three-Dimensional Paper-Based Isoelectric Focusing Device for Direct Analysis of Proteins in Physiological Samples.

On-site protein analysis is crucial for disease diagnosis in community and family medicine in which microfluidic paper-based analytical devices (μPADs) have attracted growing attention. However, the practical applications of μPADs in protein analysis for physiological samples with high complexity is still limited. Herein, we developed a three-dimensional (3D) paper-based isoelectric focusing (IEF) platform, which is composed of power supply, reservoirs, and separation channel and made by the origami and stacking method, to simultaneously separate and enrich proteins in both low-salt and high-salt samples. Under the optimized experimental conditions, standard proteins (bovine hemoglobin (BHb) and phycocyanin (Phy)) were separated within 18 min under a 36 V power supply and obtained a 10-fold enrichment using the 3D paper-based IEF platform. Then, the capability of the 3D paper-based IEF platform for direct pretreatment of high-salt samples using a 12 V battery as power supply was measured through separating three standard proteins in saline (0.9% NaCl) with separation resolution (SR) > 1.29. Through further coupling with colorimetric and lateral flow strip measurements, the 3D paper-based IEF platform was applied to directly pretreat and quantitatively analyze microalbuminuria and C-reactive proteins in clinical urine and serum samples with analytical results with relative deviations of <8.4% and < 13.1%, respectively, to the clinical test results. This work proposes a new strategy to minimize the difficulty of directly processing high-salt samples with the traditional IEF system and provides a versatile, miniaturized, and low voltage demand analytical platform for on-site analysis of proteins in physiological samples.

Metal Organic Frame-Upconverting Nanoparticle Assemblies for the FRET Based Sensor Detection of Bisphenol A in High-Salt Foods.

To resolve the occurrence of unfulfillable detection in high-salts foods, we used fluorescence resonant energy transfer (FRET) sensors based on nanoparticle upconversion. In this study, we developed a novel FRET sensor for the detection of bisphenol A (BPA) in high-salt foods. We based this approach on the assembly of aptamer modified upconversion nanoparticles (DNA1-UCNPs) and complementary DNA modified metal organic frames (DNA2-MOFs), which possessed corresponding wavelength absorption. Targeting BPA signal transduction was performed using the BPA aptamer, via competitive recognition between the BPA analyte and complementary DNA sequences in a high-salt solution. Sensor adaption in high-salt samples was attributed to functional hydrophilic groups, modified in the MOFs, and the enhanced colloidal stability of these MOFs. The MOF-UCNP assembly displayed considerable analytical performance in terms of BPA detection, with a linear range of 0.1–100 nM, and a limit of detection (LOD) of 0.02 nM, in a 340 mM NaCl food sample (the energy drink, Gatorade). Thus, this method provides a solid basis for small molecules detection in high-salt foods.

Diversity and distribution of bacteria and archaea in Tuosu Lake in Qaidam Basin

Microbes in plateau lakes are important participants of material circulation and energy flow in plateau ecosystems. Knowledge of the microbiota, such as bacteria and archaea, community distribution and diversity in plateau lakes is the basis to understand the species succession, adaptation, maintenance and metabolic mechanisms of specific environmental microbial ecosystems. This work aimed to reveal the diversity and# succession of the microbiota in Tuosu Lake to provide a biological basis for the exploration and development of microbial resources in the plateau lakes. The distribution and diversity of microflora in Tuosu Lake, hypoxia, high altitude, alkaline, closed plateau lake with fresh water supply, was investigated. The total DNA was extracted from six samples with different salinity from different geographical locations of Tuosu Lake. The 16S rRNA gene of bacteria and archaea were determined by using high-throughput sequencing-based on an Illumina Miseq sequencing platform. The microbiota in Tuosu Lake has a high diversity and complexity and there are a large number of unclassified microbial species. The bacterial communities in Tuosu Lake are dominated by Proteobacteria (44.3%) and Actbacteria (17.2%). Among them, β-Proteobacteria is the dominant genus in the low-salt sample, while γ-Proteobacteria is more advantageous in the samples with higher salinity. The archaeal communities are dominated by Euryarchaeota (50%) and Woesearchaeota__DHVEG-6 (42.6%). The vast majority of the methanogenic archaea in Tuosu Lake samples belong to Methanomicrobia, and the methanogens in low-salinity samples are significantly more abundant than those in high-salt samples. Diversity and distribution appear to be highly influenced by water salinity and pH.

Effect of high intensity ultrasound on gelation properties of silver carp surimi with different salt contents

Surimi from silver carp with different salt contents (0–5%) was obtained treated by high intensity ultrasound (HIU, 100 kHz 91 W·cm−2). The gelation properties of samples were evaluated by puncture properties, microstructures, water-holding capacity, dynamic rheological properties and intermolecular interactions. As the salt content increased from 0 to 5%, gel properties of surimi without HIU significantly improved. For samples with low-salt (0–2% NaCl) content, HIU induced obvious enhancement in breaking force and deformation. HIU promoted the protein aggregation linked by SS bonds, hydrophobic interactions and non-disulfide covalent bonds in surimi gels with low-salt content. Moreover, microstructures of HIU surimi gels with low-salt content were more compact than those of the corresponding control samples. HIU also improved the gelation properties of surimi with 3% NaCl to an extent. However, for high-salt (4–5% NaCl) samples, HIU decreased the breaking force and deformation of surimi gels due to the degradation of proteins suggested by increased TCA-soluble peptides. In conclusion, HIU effectively improved the gelation properties of surimi with low-salt content (0–2% NaCl), but was harmful for high-salt (4–5% NaCl) surimi. This might provide the theoretical basis for the production of low-salt surimi gels.

Effect of microwave sterilization on maturation time and quality of low-salt sufu.

The objective of this study was to reduce the microorganism number and salt content in pehtze by microwave sterilization. The maturation time and quality of low‐salt sufu were evaluated. The microorganism inactivation rate, moisture content and water activity of the pehtze, which was used for the growth of the starter culture, showed that 4,250 W for 30 s was suitable for the preparation of low‐salt sufu. With regard to the physicochemical properties of sufu, 120‐day sufu samples obtained by traditional high‐salt (14%) fermentation and 75‐day sufu samples obtained by low‐salt (4%) fermentation met the standard requirements. With regard to the sensory characteristics of sufu, the taste and after taste scores of 75‐day low‐salt sufu samples were significantly higher than those of 120‐day high‐salt sufu samples (p < .05).The overall acceptance score of low‐salt sufu samples also was higher than that of high‐salt sufu samples. The contents of free amino acids and the profiles of typical flavor compounds partly explained the sensory quality and shorter ripening time of sufu manufactured. The total biogenic amine contents were reduced by 46%.

Metagenomic insights into the changes in microbial community and antimicrobial resistance genes associated with different salt content of red pepper (Capsicum annuum L.) sauce

Fermented red pepper (FRP) sauce has been eaten in worldwide for many years. The salt content and resident microbial community influences the quality of the FRP sauce and may confer health (e.g., probiotics) or harm (e.g., antibiotic resistance genes) to the consumers in some circumstances; however, the salt-mediated alteration of microbial community and antibiotic resistance genes are little known. In this study, a combination of whole genome sequencing and amplicon analysis was used to investigate the changes in microbial community and antimicrobial resistance genes in response to different salt content during red pepper fermentation. While the family Enterobacteriaceae dominated in high-salt (15–25%) samples, Lactobacillaceae quickly became the dominant population in place of Enterobacteriaceae after 24 days in 10% salt samples. Compared to 0.05 antibiotic resistance genes (ARGs) per cell number on average in 10% salt sample, 16.6 ARGs were present in high-salt samples, wherein the bacterial hosts were major assigned to Enterobacteriaceae including genera Enterobacter, Citrobacter, Escherichia, Salmonella and Klebsiella. Multidrug resistance genes were the predominant ARG type. Functional profiling showed that histidine kinase functions were of much higher abundance in high-salt samples and included several osmotic stress-related two-component systems that simultaneously encoded ARGs. These results give first metagenomic insights into the salt-mediated changes in microbial community composition and a broad view of associated antibiotic resistance genes in the process of food fermentation.

Impact on the physical and sensory properties of salt-and fat-reduced traditional Irish breakfast sausages on various age cohorts acceptance

The properties of varying salt and fat levels in traditional breakfast sausages were investigated. Sausages were produced with fat levels of: 30%, 20% and 15%. Fat was replaced with pea extract. Salt levels employed were: 2.5%, 1.1% and 0.0%. A reduced sodium salt which contains 45% less sodium than standard salt was used. Sensory analysis was conducted on consumers (n = 228): 18–40 yrs., 41–64 yrs. and 65–85 yrs. The 18–40 yr. olds preferred sausages containing 20% fat, 41–64 yr. olds preferred sausages with 15% fat, 65+ age group preferred sausages containing 30% fat. The 18–40 yr. olds preferred high salt samples, 41–64 yr. olds displayed no salt preference, while the 65+ age group preferred high salt sausages. Sausage formulation choice was found to be driven by texture for the younger age cohort, flavour for the middle age cohort and visual aspects from the oldest age cohort. There is a need to understand how meat products might be reformulated different age palates.

MASS TRANSFER IN SOLID-LIQUID EXTRACTION AT HIGH SOLUTE CONCENTRATIONS

The solid-liquid extraction process and some of its influencing factors such as solid-liquid ratio, temperature and salt initial amount have been investigated. Also, mathematical modeling for mass transfer coefficients calculation was applied. An inert porous solid material (coal), impregnated with 10% and 20% mass NaCl or 15% and 30% mass CaCl2, was used. The leaching was conducted in a fixed bed column, in laminar flow. The CaCl2 impregnated samples were investigated in a column with a height/diameter ratio of 2.5, at 20 C, 30 C, and 40 C and the NaCl samples, in a 4.16 height/diameter ratio column, at 30 C, 40 C, 50 C, 60 C. In both cases, liquid flow rates of 3.8 L/h, 7 L/h, 10.6 L/h, 13.3 L/h were used. An increase of the extraction degree with the washing liquid flow rate (up to 10.6 L/h) indicated that the solid-liquid ratio is a crucial factor. Temperature increase has a positive influence on the extraction degree. At the beginning of the process, the salt quantity extracted from the high salt amount sample, using the lowest water flow rate has a similar value to the one extracted from the low salt amount sample, using the highest flow rate. At larger time values (t > 500 s), the extraction degree dependence on the liquid flow rate is similar for the high and low salt samples. Based on the proposed mathematical model, mean time mass transfer coefficient values k.a were calculated and compared to the experimental obtained data.

Elimination of Sodium Chloride Interference on Heavy Metal Analysis in High-Salt Food

A simple method using Chelex-100 chelating resin and Atomic Absorbance Spectroscopy determination of lead, cadmium and copper in high-salt food was established. This method could solve the problem of interference on the determination of lead and cadmium in salt matrix. Kd values of sodium (Na), lead (Pb), cadmium (Cd) and copper (Cu) on chelating resin was measured. The influence of pH values of solution on absorption and behavior of ions on resin were investigated. Elution curve for Na and Cd was demonstrated. Absorption capacities of resin to Pb/Cd/Cu/Na were determined. The developed method was applied for analysis of high-salt samples. The recoveries were in the range of 91.6%~98.6% with relative standard deviations (RSDs) in the range of 2.0%～6.7%.https://doi.org/10.21423/jrs-v05n02p029 (DOI assigned 3/11/2019)

Direct Analysis of Triterpenes from High-Salt Fermented Cucumbers Using Infrared Matrix-Assisted Laser Desorption Electrospray Ionization (IR-MALDESI).

High-salt samples present a challenge to mass spectrometry (MS) analysis, particularly when electrospray ionization (ESI) is used, requiring extensive sample preparation steps such as desalting, extraction, and purification. In this study, infrared matrix-assisted laser desorption electrospray ionization (IR-MALDESI) coupled to a Q Exactive Plus mass spectrometer was used to directly analyze 50-μm thick slices of cucumber fermented and stored in 1M sodium chloride brine. From the several hundred unique substances observed, three triterpenoid lipids produced by cucumbers, β-sitosterol, stigmasterol, and lupeol, were putatively identified based on exact mass and selected for structural analysis. The spatial distribution of the lipids were imaged, and the putative assignments were confirmed by tandem mass spectrometry performed directly on the same cucumber, demonstrating the capacity of the technique to deliver confident identifications from highly complex samples in molar concentrations of salt without the need for sample preparation. Graphical Abstract ᅟ.

Thermal-assisted gasification injector for analyzing high-salt solution samples: a novel device developed for online coupling of liquid chromatography with direct analysis in real time mass spectrometry

A thermal-assisted gasification injector was designed for online coupling of liquid-chromatography to direct-analysis-in-real-time mass-spectrometry. The method can be used in analysis with an inorganic salt matrix and weak polar solvent.

Determination of ultra-trace rare earth elements in high-salt groundwater using aerosol dilution inductively coupled plasma-mass spectrometry (ICP-MS) after iron hydroxide co-precipitation

Analysis data of rare earth elements (REEs) in high-salt groundwater can potentially provide a series of geochemical indicators. Accurate determination of sub-ng L−1 levels of REEs by inductively coupled plasma-mass spectrometry (ICP-MS) is still a challenge because of low concentrations, significant matrix effects from the highly dissolved salts, and mass spectral interferences. A reliable method, based on online aerosol dilution ICP-MS after co-precipitation with Fe(OH)3, was evaluated for the determination of REEs in high-salt groundwater. First, an Fe(OH)3 co-precipitation procedure effectively separated the target REEs from the high-content matrix elements (i.e. K, Na, Ca, and Mg); over 93% of the matrix elements were removed and target REEs were concentrated 15-fold. Secondly, using the proposed online aerosol dilution technique resulted in diminished residual matrix effects and the reduction of mass spectral interferences from oxide ions (i.e. Ba and light REE-oxides) by up to 10-fold. The detection limits of the method ranged from 0.05ngL−1 for Lu to 0.6ngL−1 for Nd, with the REE recoveries between 90% and 125%. The results for a seawater standard reference material (NASS-6) agreed with literature reported values. The proposed method was employed for the analysis of five high-salt groundwater samples. The accurate results showed that this method has great potential for the determination of ultra-trace levels of REEs in various high-salt water samples.

Determination of cadmium, chromium and copper in high salt samples by LA-ICP-OES after electrodeposition—preliminary study

A novel method is presented for determination of heavy metal ions in a high-saline matrix. It is based on the electrodeposition of the ions and subsequent laser ablation coupled to inductively coupled plasma optical emission spectrometry (LA-ICP-OES). Three arrangements for electrodeposition were worked out, two of them with stationary working electrodes. Materials for use in the working electrodes, and conditions for electrodeposition of Cd, Cr and Cu (pH, deposition current, time of electrolysis) were studied. Nickel was found to be the best electrode material. The metals accumulate on the surface of electrode and were then evaporated/ablated with a Nd:YAG laser focused into the ICP-OES spectrometer. The detection limits are 0.13 mg L−1 for Cd, 0.15 mg L−1 for Cu, and 1.9 mg L−1 for Cr in case of a stationary bottom working electrode, and 0.25 mg L−1 for Cd, 0.05 mg L−1 for Cu, 0.8 mg L−1 for Cr when using a rotating electrode. The relative standard deviation is in range from 3.8 to 10.3%. Waste water was analyzed in this way by the standard addition method.

Capillary electrophoresis determination of nitrate and nitrite in high-salt perchlorate solutions for the UC dissolution study

The capillary electrophoresis method with direct UV detection is proposed for the determination of nitrite and nitrate in high-salt perchlorate solutions issued from uranium carbide dissolution. The isotachophoretic sample stacking was used to compensate for the perchlorate matrix interference. Simple electrolyte composed of 120 mM formiate buffer, pH 3.8 enabled the nitrate and nitrite determination in the presence of up to 1000-fold excess of perchlorate with 2 µM and 4 µM detection limits for nitrate and nitrite, respectively. The proposed method was applied to the determination of nitrate and nitrite in high-salt non-irradiated uranium carbide dissolution samples.

Convergence of Heat Shock Protein 90 with Ubiquitin in Filamentous α-Synuclein Inclusions of α-Synucleinopathies

Convergence of Heat Shock Protein 90 with Ubiquitin in Filamentous α-Synuclein Inclusions of α-Synucleinopathies