Syringe Filter Research Articles

Minimizing Contamination from Plastic Labware in the Quantification of C16 and C18 Fatty Acids in Filter Samples of Atmospheric Particulate Matter and Their Utility in Apportioning Cooking Source Contribution to Urban PM2.5

Palmitic acid (C16:0) and stearic acid (C18:0) are among the most abundant products in cooking emission, and thus could serve as potential molecular tracers in estimating the contributions of cooking emission to particulate matter (PM2.5) pollution in the atmosphere. Organic tracer analysis in filter-based samples generally involves extraction by organic solvents, followed by filtration. In these procedures, disposable plastic labware is commonly used due to convenience and as a precaution against sample-to-sample cross contamination. However, we observed contamination for both C16:0 and C18:0 fatty acids, their levels reaching 6–8 ppm in method blanks and leading to their detection in 9% and 42% of PM2.5 samples from Hong Kong, indistinguishable from the blank. We present in this work the identification of plastic syringe and plastic syringe filter disc as the contamination sources. We further demonstrated that a new method procedure using glass syringe and stainless-steel syringe filter holder offers a successful solution. The new method has reduced the contamination level from 6.6 ± 1.2 to 2.6 ± 0.9 ppm for C16:0 and from 8.9 ± 2.1 to 1.9 ± 0.8 ppm for C18:0 fatty acid. Consequently, the limit of detection (LOD) for C16:0 has decreased by 57% from 1.8 to 0.8 ppm and 56% for C18:0 fatty acid from 3.2 to 1.4 ppm. Reductions in both LOD and blank variability has allowed the increase in quantification rate of the two fatty acids in ambient samples and thereby retrieving more data for estimating the contribution of cooking emission to ambient PM2.5. With the assistance of three cooking related tracers, palmitic acid (C16:0), stearic acid (C18:0) and cholesterol, positive matrix factorization analysis of a dataset of PM2.5 samples collected from urban Hong Kong resolved a cooking emission source. The results indicate that cooking was a significant local PM2.5 source, contributing to an average of 2.2 µgC/m3 (19%) to organic carbon at a busy downtown roadside location and 1.8 µgC/m3 (15%) at a general urban site.

Dimethyl 3,3\u2032-dithiobispropionimidate-functionalized diatomaceous earth particles for efficient biomolecule separation

The early diagnosis and monitoring of cancers are key factors in effective cancer treatment. Particularly, the separation of biomolecules is an essential step for both diagnostic and analytical purposes. However, the current techniques used to isolate biomolecules are intensive, laborious, and require multiple instruments as well as repeated sample preparations to separate each biomolecule. Thus, an efficient separation system that can simultaneously separate biomolecules from scarce samples is highly desirable. Hence, in this study, we developed a biosilica-based syringe filtration system for the efficient separation of biomolecules from cancer samples using amine-modified diatomaceous earth (AD) with dimethyl 3,3′-dithiobispropionimidate (DTBP). The syringe filter can be an efficient and rapid tool for use in various procedures without complex instruments. The DTBP-based AD system was combined with the syringe filter system for nucleic acid and protein separation from various cancer cells. We demonstrated the efficacy of the DTBP-based AD in a single-filter system for the efficient separation of DNA and proteins within 40 min. This DTBP-based AD syringe filter system showed good rapidity, efficiency, and affordability in the separation of biomolecules from single samples for the early diagnosis and clinical analysis of cancers.

In-house validation method for quantification of formaldehyde in silage and feedingstuffs with the use HPLC-DAD technique.

An HPLC-DAD method was developed for the determination of formaldehyde in animal feed and silage. The method is based on the determination of the product of chemical reaction between formaldehyde and 2,4-dinitrophenylhydrazine. A 3 g of feed or silage were extracted with Milli-Q water with phosphoric acid and next formaldehyde was derivative with the use 2,4-dinitrophenyl- hydrazine in acetronitrile solution. The extract was purified with 0.45 µm syringe filters and separeted on Zorbax Eclipse XDB C18 column and detection was carried out at 360 nm. Formal- dehyde was eluted with a mobile phase consisting of acetonitrile/water in isocratic elution. This method provided average recoveries of 90.6% to 102.2%, with CVs of 2.6% to 6.4% for feed and from 91.3% to 108.7% with CVs of 1.1% to 4.1% for silage in the ranged of 50 to 1000 mg/kg feeds and silage. The LOD and LOQ for formaldehyde in feed and silage ranged from 1.6 to 2.6 and 2.7 to 5.7 mg/kg, respectively. The methodology was applied for the analysis of feed and silage samples collected from poultry, pigs and cows farms.

Multi-Sample Preparation Assay for Isolation of Nucleic Acids Using Bio-Silica with Syringe Filters.

The spin-column system for the isolation of nucleic acids (NAs) from multiple samples presents the inconvenience of repeated experimentation, time-consumption, and the risk of contamination in the process of the spin-column exchange. Herein, we propose a convenient and universal assay that can be used to diagnose multiple pathogens using a multi-sample preparation assay. The multi-sample preparation assay combines a 96-well filter/membrane plate, a bio-micromaterial lattice-like micro amine-functional diatomaceous earth (D-APDMS), and homobifunctional imidoesters (HI) for the processing of pathogen enrichment and extraction for multiple samples simultaneously. The purity and quantity of the extracted NAs from pathogens (E. coli and Brucella) using the proposed assay is superior to that of the commercialized spin-column kit. The assay also does not require the replacement of several collection tubes during the reaction processing. For the multi-sample testing, we used as many as six samples simultaneously with the proposed assay. This assay can simultaneously separate up to 96 NAs from one plate, and the use of multichannel pipettes allows faster and simpler experimentation. Therefore, we believe it is a convenient and easy process, and can be easily integrated with other detection methods for clinical diagnostics.

Elimination of interfering molybdenum oxyanion with an anion-exchange monolithic spin tip (AXTip) for precise determination of cadmium in human urine by ICP-MS

A simple purification technique using an anion-exchange monolithic spin tip was described for the elimination of molybdenum oxyanion interfering with precise determination of cadmium in human urine samples by ICP-MS. The tip device named “anion-exchange tip-in monolith (AXTip)” was laboratory-prepared within the confines of a commercially available syringe filter tip by a two-step process: (1) in situ copolymerization of glycidyl methacrylate (GMA) and ethylene dimethacrylate (EDMA) and (2) its subsequent modification with trimethylamine (TMA), as a strong anion-exchange functional group, via ring-opening reaction of epoxide. The adsorption capacity of the AXTip was > 3.2 μmol/tip for molybdenum oxyanion. The performance of the AXTip was evaluated through an adsorption/non-adsorption experiment for molybdenum, cadmium and other metal and metalloid species, using a model solution and human urine samples to optimize the sample solution's pH and dilution factor for the AXTip treatment. In the case of urine sample analysis, 8 times dilution and pH adjustment to 4.0 prior to AXTip treatment were found to allow > 98% elimination of interfering molybdenum oxyanions and quantitative recovery (103 ± 7%) of cadmium. At the optimized conditions, the AXTip treatment reduces Mo/Cd ratio from ~400 in human urines to < 10, which is sufficient for conducting ICP-MS measurement of cadmium in no-gas mode (without collision/reaction cell technique). The proposed purification technique was validated through the analysis of an accuracy control material of human urine (Seronorm™ Trace Elements Urine L-1). Good agreement of the observed values with the reference values indicates that the proposed technique is practically applicable.

Efficient whole brain transduction by systemic infusion of minimally purified AAV-PHP.eB

BackgroundAdeno-associated virus (AAV) vectors have excellent properties as gene transfer vehicles. The recent development of AAV-PHP.eB, highly BBB-permeable capsid variant of AAV serotype 9, has opened up systemic application for whole brain transduction. To attain high transduction efficacy, much efforts have been paid to purify AAV vectors using gradient centrifugation or column chromatography. These methods are time-consuming, cost substantially and require expensive equipment. New methodWe propose a simple purification method for the production of systemically applicable AAV-PHP.eB targeting the brain. The new method, which we named minimal purification (MP) method, requires only 2 steps: removal of cell debris using a syringe filter and concentration using a disposable ultrafiltration device. ResultsThe MP method yielded 2 times more AAV-PHP.eB than the standard ultracentrifuge purification (UCP) method. Intravenous injection of AAV-PHP.eB prepared using the MP method caused robust whole brain transduction without overt toxicity on the liver and kidney. Moreover, we found almost no difference in cellular density and morphology of brain microglia between control mice and mice treated systemically with the MP viral solution, suggesting no influence of the viral injection on brain immunity. Comparison with existing methodsThe new method, which requires only a benchtop centrifuge and takes only 2–4 h to obtain a ready-to-use viral solution, is much less expensive than the existing UCP method, and can avoid cumbersome and time-consuming purification processes. ConclusionsThis simplified method further expands the use of AAV vectors in the neuroscience community.

Microfiltration results in the loss of analytes and affects the in vitro genotoxicity of a complex mixture of Alternaria toxins

Alternaria molds produce a variety of chemically diverse secondary metabolites with potentially adverse effects on human health. However, data on occurrence in food and human exposure is inconsistent for some of these mycotoxins. Membrane filtration is a frequent step in many sample preparation procedures for LC-MS-based methods analyzing food contaminants. Yet, little is known about the possibility of adsorptive phenomena that might result in analyte losses. Thus, we treated a complex extract of Alternaria toxins with several types of syringe filters and unraveled the impact on its chemical composition by LC-MS/MS. We observed significant, and in some cases complete, losses of compounds due to filtration. Particularly, two key Alternaria toxins, alternariol (AOH) and its monomethyl ether (AME), were heavily affected. As a comparison with published food surveys indicating a correlation of the type of filtration used with lower incidence reports in food, our results point at a possible underestimation of AME in past exposure assessment. Also, perylene quinones were greatly affected by filtration, underlining the importance to take this into consideration during analytical method development. Furthermore, we applied the comet assay in HT-29 cells to elucidate the impact of filtration on the genotoxicity of the extract. We observed strong coincidences with the loss of epoxide-carrying metabolites and also an intriguing induction of oxidative DNA damage by yet toxicologically uncharacterized Alternaria toxins. In conclusion, we highlight potential issues with sample filtration and call for a critical re-evaluation of previous food occurrence data in the light of the results at hand.

In Vitro Release Study of the Polymeric Drug Nanoparticles: Development and Validation of a Novel Method.

The in vitro release study is a critical test to assess the safety, efficacy, and quality of nanoparticle-based drug delivery systems, but there is no compendial or regulatory standard. The variety of testing methods makes direct comparison among different systems difficult. We herein proposed a novel sample and separate (SS) method by combining the United States Pharmacopeia (USP) apparatus II (paddle) with well-validated centrifugal ultrafiltration (CU) technique that efficiently separated the free drug from nanoparticles. Polymeric drug nanoparticles were prepared by using a four-stream multi-inlet vortex mixer with d-α-tocopheryl polyethylene glycol 1000 succinate as a stabilizer. Itraconazole, cholecalciferol, and flurbiprofen were selected to produce three different nanoparticles with particle size <100 nm. By comparing with the dialysis membrane (DM) method and the SS methods using syringe filters, this novel SS + CU technique was considered the most appropriate in terms of the accuracy and repeatability to provide the in vitro release kinetics of nanoparticles. Interestingly, the DM method appeared to misestimate the release kinetics of nanoparticles through separate mechanisms. This work offers a superior analytical technique for studying in vitro drug release from polymeric nanoparticles, which could benefit the future development of in vitro-in vivo correlation of polymeric nanoparticles.

Environmental Detection of Brilliant Blue, Sunset Yellow and Tartrazine Using Direct Injection HPLC-DAD Technique

A newly developed direct injection HPLC-DAD method for the simultaneous detection of Brilliant Blue (BB), Sunset Yellow (SY) and Tartrazine (TA) synthetic dyes was validated and applied to surface and wastewater samples. Chromatographic separation was achieved using an Acclaim Surfactant Plus column (150 x 3.0 mm, 3 um) in isocratic elution mode with a mobile phase consisting of 100 mM CH3COONH4 and ACN in the ratio 50/50 (v/v). Linear calibration curves were plotted in the range of 2-100 μg/L (BB) and 6-300 μg/L (SY, TA) respectively with correlation coefficients (R2) higher than 0.99. Low quantitation limit values (LOQ) were obtained for the direct injection HPLC-DAD method, namely: 1.0 �g/L (BB), 5.5 �g/L (SY) and 5.8 �g/L (TA), respectively. The entire sample preparation procedure consisted only in simple filtration using PTFE syringe filters (0.45 �m) without sample extraction or concentration, which improved method accuracy and precision. HPLC-DAD developed method proved to be fast (6 minutes run-time), sensitive and accurate and was succesfully applied for the analysis of the synthetic dyes in surface and wastewater samples. Considering all analyzed samples (8 surface water and 11 wastewater samples), Brilliant Blue was found in influent samples with values between 4.49 � 14.17 �g/L and effluent samples with values between 1.07 � 9.54 �g/L, whereas Sunset Yellow and Tartrazine were not detected in any of the analyzed samples.

Determination of anabasine, anatabine, and nicotine biomarkers in wastewater by enhanced direct injection LC-MS/MS and evaluation of their in-sewer stability

Wastewater-based epidemiology (WBE) has been used to estimate tobacco use in the population. However, the increased use of nicotine replacement therapies and e-cigarettes contributes to the load of nicotine metabolites in wastewater, causing over-estimation of tobacco use if nicotine metabolites were used in WBE back-estimation. This study aims to develop a rapid method for determining the tobacco-specific biomarkers, anabasine and anatabine, in wastewater and to evaluate their in-sewer stability for better estimation of tobacco use by WBE. An enhanced direct injection LC-MS/MS was developed to quantify anabasine and anatabine as well as nicotine biomarkers (nicotine, cotinine and hydroxycotinine). The method was optimal when wastewater was filtered through 0.2 μm RC syringe filters and a pre-conditioned SPE cartridge (Oasis HLB 1 cc, 30 mg) before 50 μL was injected into the LC-MS/MS system. Limits of quantification varied between 2.7 and 54.9 ng/L with recoveries from 76% to 103% for all five compounds. In sewer reactors, anabasine and anatabine were less stable than cotinine and hydroxycotinine. They were more stable in the gravity sewer reactor with <20% loss in 12 h than in the rising main sewer reactor with ~30% loss in the same period. We then applied the new method to 42 daily wastewater influent samples collected from an Australian wastewater treatment plant. The five biomarkers were detected in all samples with concentrations ranging from 9.2 to 7430 ng/L. All five compounds were positively correlated with one another. Our results suggested a high throughput analytical method for feasible application in anabasine and anatabine as biomarkers of tobacco use in routine wastewater monitoring.

Schistosoma haematobium Infection among the Students of Government Day Junior Secondary School Garki, Jigawa-Nigeria

Schistosomiasis is among the most prevalent but neglected tropical diseases (NTDs). It is a human disease caused by the parasitic infection of the blood trematode worm belonging to the family Schistosomatidae A descriptive cross-sectional study was carried out to evaluate the prevalence and intensity of Schistosoma haematobium infection among the students of the Government Day Junior Secondary School (GDJSS) Garki in Jigawa State for a period of 17 days. A total of 120 students from class 1-3, who randomly participated in the study, were diagnosed for the S. haematobium infection. The intensity of the infection was assessed by counting and recording the number of eggs present in the 10ml urine samples of the positive individuals. The results obtained showed a 25% prevalence of the S. haematobium infection among the students. The students in contact with the water bodies in the community were infected more as compared to the students who did not have any contact with the water bodies (odd ratio = 0.002). The positive predictive value recorded at 93.3% quantified the diagnostic test employed (syringe filtration method) and the negative predictive value of 97.8% showed that the prevalence of S. haematobium infection was marginal among the student population. The gender of the students did not relate significantly (p &lt; 0.05) with the results of the diagnosis, as more male students were infected than female students (odd ratio = 1.455). The students’ age group related significantly (p &lt; 0.05) with the results and the students of the age group 14-15 years were more infected than those of the age group 12-13 years (odd ratio = 0.337). There were many more eggs in the urine samples of the positive students than the Poisson distribution would predict. Therefore, the model assumes that the intensity of S. haematobium infection is very high and thus the students should be treated and prevented from further exposure.

Schistosoma haematobium Infection among the Students of Government Day Junior Secondary School Garki, Jigawa-Nigeria

Schistosomiasis is among the most prevalent but neglected tropical diseases (NTDs). It is a human disease caused by the parasitic infection of the blood trematode worm belonging to the family Schistosomatidae A descriptive cross-sectional study was carried out to evaluate the prevalence and intensity of Schistosoma haematobium infection among the students of the Government Day Junior Secondary School (GDJSS) Garki in Jigawa State for a period of 17 days. A total of 120 students from class 1-3, who randomly participated in the study, were diagnosed for the S. haematobium infection. The intensity of the infection was assessed by counting and recording the number of eggs present in the 10ml urine samples of the positive individuals. The results obtained showed a 25% prevalence of the S. haematobium infection among the students. The students in contact with the water bodies in the community were infected more as compared to the students who did not have any contact with the water bodies (odd ratio = 0.002). The positive predictive value recorded at 93.3% quantified the diagnostic test employed (syringe filtration method) and the negative predictive value of 97.8% showed that the prevalence of S. haematobium infection was marginal among the student population. The gender of the students did not relate significantly (p &lt; 0.05) with the results of the diagnosis, as more male students were infected than female students (odd ratio = 1.455). The students’ age group related significantly (p &lt; 0.05) with the results and the students of the age group 14-15 years were more infected than those of the age group 12-13 years (odd ratio = 0.337). There were many more eggs in the urine samples of the positive students than the Poisson distribution would predict. Therefore, the model assumes that the intensity of S. haematobium infection is very high and thus the students should be treated and prevented from further exposure.

Has the formation of disinfection by-products been overestimated? Membrane leakage from syringe filter heads serves as unexpected precursors

Syringe filters are widely used for sample pretreatments in laboratories. This study found that, surprisingly, these filters can leak dissolved organic carbon (DOC) that can potentially serve as precursors of disinfection by-products (DBPs). Nine common types of syringe filters were assessed. The results showed that the DOC of ultrapure water increased after syringe filtration. The DOC shed from filter membranes was characterized, whose spectra showed that the main compounds exhibited a low apparent molecular weight. Five classes of DBPs were investigated including trihalomethanes, haloacetaldehydes, haloacetonitriles, haloacetamides and halonitromethanes, among which trichloromethane (TCM), dichloroacetaldehyde (DCAL), trichloroacetaldehyde (TCAL), dichloroacetonitrile (DCAN), and trichloronitromethane (TCNM) were principally detected. The DBP formation was affected by chlorination time and membrane types. In general, the use of the poly vinylidene fluoride membrane resulted in the highest formation of TCM and TCAL, whereas nylon and mixed cellulose esters membranes contributed significantly to the formation of DCAN and TCNM, respectively. The shedding DOC and the formation of TCM, DCAL and TCAL from filter membranes were mitigated effectively by pre-washing; however, the contribution of membrane leakage to DCAN and TCNM formation was still notable, even with a pre-wash volume of 50 mL. When unwashed syringe filters were used for a real water sample, the DBP formation increased by up to 73.2% compared to the pre-washed ones; particularly for TCNM it was always over 15%. Therefore, for better quality control in laboratories, more attention should be paid to the syringe filters during sample pre-treatments, particularly when DBP formation is being investigated.

Simple Paper-based Liver Cell Model for Drug Screening

Investigation of the potential adverse effects of chemicals and drugs is essential during the drug development process. In vitro cell model systems have been developed over the past years towards such toxicity investigation. 96-well plate is the common platform for screening drug toxicity due to its simplicity. However, this platform only offers 2D cell culture environment and lacks the flow of solutions, which fails to provide the suitable environment for the cells to adequately metabolize the drugs, for the media to replenish, and for the metabolites and wastes to be removed. Microfluidic chips populated with human or animal cells, known as organ-on-a-chip (OOC), can reconcile many issues of in vitro cell models, such as the lack of extracellular matrix and flow as well as the species difference. However, OOC can be complicated to fabricate and operate. To bridge this gap, we utilized paper as a primary substrate for OOC, considering its fibrous structure that can mimic natural extracellular matrix, as well as a syringe pump and filter that are commonly available in most laboratories. Paper microfluidic model was designed and fabricated by wax printing on nitrocellulose paper, seeded and proliferated with liver cells (primary rat hepatocytes and HepG2 cells), and two paper substrates were stacked together to complete the paper model. To this paper-based liver cell model, the following drugs were added: Phenacetin (pain reliever and fever reducer), Bupropion (antidepressant), Dextromethorphan (antidepressant), and phosphate-buffered saline (PBS) as a control, all under a physiologically relevant flow rate. The combination of these drugs with Fluconazole (antifungal drug) was also investigated. Cell count, cell morphology, protein production, and urea secretion after drug treatment confirmed that the model successfully predicted toxicity within 40 minutes. This simple, paper-based liver cell model provided enhanced and faster cell response to drug toxicity and showed comparable or better behavior than the cells cultured in conventional 2D in vitro models.

Leukocyte depletion and recovery with white blood cell sterile acrodisc® syringe filter

Background & Aim State of the art research laboratories with activities based on leukocyte recovery or depletion, demand new options to accommodate current testing needs. In this context, the ability to quickly process large number of samples under laboratory conditions requires an optimized product design for leukocyte recovery or depletion. This study evaluates the performance of Pall's sterile Acrodisc® WBC syringe filter by means of red blood cell (RBC) recovery (leukocyte depletion) in the filtrate, as well as white blood cell (WBC) recovery and viability before and after filtration of human whole blood samples. Methods, Results & Conclusion For this, whole human blood samples were collected and preserved using EDTA coated vacutainers, and tested within 36 hours after collection. WBC concentration was determined by flow cytometry before and after filtration of the whole blood samples. This process required a) whole blood analysis, b) flow cytometry sample preparation by whole blood filtration, and c) WBC recovery wash. Results on leukocyte depletion experiments shown over 99% removal of WBC's from the samples in all cases studied. Additionally, the sterile Acrodisc® WBC syringe filter was able to recover about 60 % of WBCs after the backflush step. Obtained viability of WBC on whole blood samples was about 94 %, and on the recovered leukocytes was about 80 %. Results from flow cytometry data on leukocyte depletion and WBC recovery are depicted on Figure 1, and on Figure 2 those corresponding to WBC viability. Pall's sterile Acrodisc® WBC syringe filter is a proven filtration device designed to capture and recover leukocytes for further analysis of WBC's, or alternatively, removal of WBCs to produce leukodepleted blood samples. This is an established tool for processing up to 12 mL of whole blood samples in research laboratories equipping scientists with a simple and efficient method to isolate or remove white blood cells. State of the art research laboratories with activities based on leukocyte recovery or depletion, demand new options to accommodate current testing needs. In this context, the ability to quickly process large number of samples under laboratory conditions requires an optimized product design for leukocyte recovery or depletion. This study evaluates the performance of Pall's sterile Acrodisc® WBC syringe filter by means of red blood cell (RBC) recovery (leukocyte depletion) in the filtrate, as well as white blood cell (WBC) recovery and viability before and after filtration of human whole blood samples. For this, whole human blood samples were collected and preserved using EDTA coated vacutainers, and tested within 36 hours after collection. WBC concentration was determined by flow cytometry before and after filtration of the whole blood samples. This process required a) whole blood analysis, b) flow cytometry sample preparation by whole blood filtration, and c) WBC recovery wash.

Sequential injection solvent dispersive micro solid phase extraction (SI-SD-μSPE) platform coupled with atomic absorption spectrometry for lead determination in water samples

A novel automatic versatile sequential injection solvent dispersive micro solid phase extraction platform coupled with flame atomic absorption spectrometry is developed for the first time. The analytical procedure is based on chemical dispersion of benzophenone and ternary component systems. The full dispersion of sorbent into the aqueous phase, in the shape of micro particles, is achieved by on-line mixing of the two flows; a small flow of methanol containing the sorbent in a low concentration and a higher one of the aqueous sample solution. The resulted cloudy mixture is consisted of sorbent's fine particles, which are dispersed into the whole aqueous phase. Via this continuous process, metal chelating complexes are retained onto the sorbent particles. An integrated, easy and fast reusable syringe filter was studied for the on-line collection and dissolution of the sorbent. The potentials of this novel schema were demonstrated for trace Pb(II) determination in water samples. All the critical parameters affecting the performance of the proposed method were optimized. For a sample consumption of 11.0 mL, the working range was 5.28–400.0 μg L−1, while the enhancement factor, the detection limit and the relative standard deviation were 120, 1.59 μg L-1 and 2.4% (at 50.0 μg L−1) respectively. The developed method was evaluated by analyzing certified reference materials and applied to the analysis of environmental water samples.

Rumen fluid metabolomics of beef steers differing in feed efficiency.

Beef is the most consumed red meat in the United States, and the US is the largest producer and consumer of beef cattle globally. Feed is one of the largest input costs for the beef cattle industry, accounting for 40-60% of the total input costs. Identifying methods for improving feed efficiency in beef cattle herds could result in decreased cost to both producers and consumers, as well as increased animal protein available for global consumption. In this study, rumen fluid was collected from low- (n = 14) and high-RFI (n = 15) steers. Rumen fluid was filtered through a 0.22µM syringe filter, extracted using 0.1% formic acid in acetonitrile:water:methanol (2:2:1) and injected into the Dionex UltiMate 3000 UHPLC system with an Exactive Plus Orbitrap MS. Peaks were identified using MAVEN and analyzed using MetaboAnalyst 4.0 and SAS. Significance was determined using an α ≤ 0.05. Eight metabolites were greater in low-RFI steers compared to high-RFI steers, including 3,4-dihydroxyphenylacetate, 4-pyridoxate, citraconate, hypoxanthine, succinate/methylmalonate, thymine, uracil, and xylose (P ≤ 0.05). These metabolites were predominantly involved in amino acid and lipid metabolism. Rumen fluid metabolomes differ in steers of varying feed efficiencies. These metabolites may be used as biomarkers of feed efficiency, and may provide insight as to factors contributing to differences in feed efficiency that may be exploited to improve feed efficiency in beef cattle herds.

Sensitive detection of choline in infant formulas by SERS marker transformation occurring on a filter-based flexible substrate

In this study, we developed a simple and sensitive surface-enhanced Raman scattering (SERS) technique for the detection of choline in infant formulas based on a filter-based flexible substrate. The flexible substrate with excellent SERS activity and reproducibility was fabricated using a syringe filter and Ag triangular nanoplates. The Raman marker, 3-mercaptophenylboronic acid, was oxidised to 3-hydroxythiophenol in the presence of H2O2, which caused a decrease in the SERS peak intensity ratio (I1021 cm−1: I996 cm−1). Utilising the enhanced flexible substrate, a quantitative detection method for H2O2 was developed. Additionally, choline could be hydrolysed by choline oxidase to generate betaine and H2O2. Thus, the SERS method was successfully applied to detect choline in the concentration range of 10-3–10-7 M with a beneficial limit of detection as low as 8.36 nM. Importantly, the recovery of choline from infant formula milk powder was approximately 99 %. The excellent performance of the flexible substrate-based SERS method demonstrated its potential for application in H2O2-generated oxidase-based biosensing.

Ultrasound assisted-dispersive-modification solid-phase extraction using task-specific ionic liquid immobilized on multiwall carbon nanotubes for speciation and determination mercury in water samples

An efficient method based on 1-(3-aminopropyl)-3-methylimidazolium hexafluorophosphate (TSIL) immobilized on multiwall carbon nanotubes (MWCNTs@ [Apmim][PF6]) was used for speciation of inorganic/organic mercury (Hg2+, R-Hg or O-Hg) by ultrasound assisted-dispersive modification solid-phase extraction (UAS-DM-SPE) which was combined with cold vapor atomic absorption spectrometry (CV-AAS). The mixture of MWCNTs @ [Apmim][PF6] in acetone was injected to water samples in polypropylene syringe filters (PSF) which was already adjusted pH up to 8.5. After shaking, the Hg(II) and O-Hg were simply extracted on amine group of [Apmim][PF6] as TSIL and then, separated from the liquid phase by pushing plunger of PSF. The Hg(II) and O-Hg loaded in MWCNTs @ [Apmim][PF6] were back-extracted based on the eluent solution (HNO3, 0.5 mL, 0.2 mol L−1) with/without microwave system (UV radiation at 165 °C). Finally, the concentration of mercury was determined by CV-AAS. By microwave, organic mercury species in remained solution were changed to Hg (II) and the total amount of mercury (T-Hg) was determined. Finally, O-Hg concentration was computed by subtracting the Hg (II) concentration from T-Hg. Under the optimized conditions, the linear range, LOD and enrichment factor for Hg (II) and O-Hg were achieved (0.02–3.6 μg L−1; 0.02–3.4 μg L−1), (5.2 ng L−1; 5.8 ng L−1) and (19.9; 19.7), respectively (Mean of RSD<1.91%). Also, the capacity absorption based on MWCNTs and MWCNTs@ [Apmim][PF6] for O-Hg and Hg(II) ions were achieved 23.6/27.3 mg g−1 and 174.3/186.2 mg g−1, respectively. The proposed method validated for speciation of mercury by ICP-MS and standard reference material (SRM).

Thymoquinone content in marketed black seed oil in Malaysia.

ABSTRACTThymoquinone (TQ) is the major active compound in black seed oil (BSO). Many pharmacological effects of TQ, such as anti-inflammatory, hypoglycemic, antioxidant, immune stimulator, and anticancer, have been reported. TQ can be considered as a biomarker for BSO, but its content in the commercial products is rarely reported. TQ content varies based on the oil source and extraction method. This study aimed to quantify the TQ content in the commercial BSO products in Malaysia and to evaluate whether the products can be used as a source of TQ for therapeutic benefits. TQ was quantified using an established high-performance liquid chromatography (HPLC) method. TQ human equivalent dose (HED) was calculated based on reported animal studies from literature, and theoretical BSO amount containing the TQ dose was calculated based on the HPLC analysis. TQ content in the commercial BSO products ranged from 0.07% wt/wt to 1.88% wt/wt. The product with the highest TQ concentration is approximately 27-fold higher than the product with the lowest TQ concentration. Consequently, theoretical BSO amounts needed for specific diseases varied and some products cannot provide practical amount of TQ. This study recommends the regulation of TQ content in BSO and suggests that the BSO might be fortified with extra TQ to be effectively used in some diseases.