Syringe Membrane Research Articles

TiO2@SiO2 flexible nanofiber membrane-based syringe membrane solid phase extraction for determination of beryllium in Chinese yellow rice wine samples by graphite furnace atomic absorption spectrometry

TiO2@SiO2 flexible nanofiber membrane-based syringe membrane solid phase extraction for determination of beryllium in Chinese yellow rice wine samples by graphite furnace atomic absorption spectrometry

Solidified floating organic drop microextraction in tandem with syringe membrane miro-solid phase extraction for sequential detection of thallium (III) and thallium (I) by graphite furnace atomic absorption spectrometry

In the present study, a novel method based on solidified floating organic drop microextraction (SFODME) combined with syringe membrane micro-solid phase extraction (SMMSPE) was proposed for the sequential separation and enrichment of Tl(III) and Tl(I) followed by graphite furnace atomic absorption spectrometry detection. In SFODME, Tl(III) can react with 1-(2-Pyridylazo)-2-naphthol at pH 8.0 to form the complexes which can be extracted into an organic drop, while Tl(I) was remained in the solution. In SMMSPE, flexible TiO2@SiO2 nanofiber membrane was used as the sorbent for the enrichment of Tl(I) in the sample solution after the separation of Tl(III). This method did not require tedious pre-oxidation/pre-reduction operation and time-consuming centrifugation/filtration steps, which may cause sample contamination and analysis errors. Main parameters influencing the separation and enrichment of the target species were studied. Under the selected conditions, the detection limits for this method were 1.7 and 2.6 ng/L for Tl(III) and Tl(I) with relative standard deviations of 6.1 % and 5.2 %, respectively. This method was successfully used for the determination of the target species in environmental water samples and two certified reference materials. The determined values were in good agreement with the certified values.

Syringe Membrane Micro-Solid-Phase Extraction (SPE) with Flexible Titanium(IV) Oxide@Silica Nanofiber Membrane for the Speciation of Te(IV) and Te(VI) with Graphite Furnace Atomic Absorption Spectrometry (GFAAS)

In this work, syringe membrane micro-solid phase extraction (SMMSPE) was described for the enrichment and separation of Te(IV) and Te(VI) prior to graphite furnace atomic absorption spectrometry detection. SMMSPE device is composed of a syringe and a disk filter, which was filled with flexible titanium(IV) oxide@silica nanofiber membrane as the sorbent. The adsorption behavior of Te(IV) and Te(VI) on the sorbent was studied in detail. The results showed that Te(IV) was quantitatively adsorbed on the sorbent in the pH range of 3.0-5.0, while Te(VI) remained in the aqueous phase. Te(VI) content was obtained by subtracting Te(IV) from total Te concentration. Total Te was detected after reducing Te(VI) into Te(IV). The key factors affecting the extraction efficiency and determination of target species were investigated. Under the selected conditions, the limit of detection was 1.8 ng L−1 for Te(IV). The precision expressed as relative standard deviation was 5.7% (n = 9). This method was utilized for the determination of Te(IV) and Te(VI) in environmental water samples with satisfactory results. To verify this method, a certified reference material of water sample was analyzed, and the obtained result was in good agreement with the certified value. Besides, the developed sorbent exhibited good efficiency, flexibility and recyclability.

On the issue of analytical control of quinone derivatives in habitats

Introduction. In the direction of normative and methodological assurance of the safety of environmental objects and imported food products, analytical approaches to the determination of a fungicide of the quinone class - dithianone in the air and citrus fruits were optimized. Materials and methods. Measurements were performed by tandem liquid mass spectrometry with a triple quadrupole mass detector (HPLC-MS/MS) in multiple reaction monitoring (MRM) mode using electrostatic spray as the ionization source. The substance from the air was concentrated on Tenax TA sorption tubes based on a porous polymer sorbent, followed by extraction of dithianone from the tubes with acetone. The preparation of samples of citrus fruits was carried out by extraction of acidified acetonitrile (selected optimal pH 2) in the presence of salts of magnesium sulfate, sodium chloride and sodium citrate two- and three-substituted, followed by centrifugation and filtration of the extract through disposable syringe membrane filters (QuEChERS technology). Results. The developed techniques were tested on real samples using the pesticide in agricultural practice. The revealed levels of dithianon do not exceed the lower limit of quantitative determination: 0.000071 mg/m3 in ambient air (with an RISL value of 0.0001 mg/m3) and 0.01 mg/kg in citrus fruits (with an established MRL value of 3 mg/kg). Conclusion. The developed methods are approved as official documents and supplement the base of analytical methods in terms of control of atmospheric air and imported food products.

Electrospun Fibers of Polybutylene Succinate/Graphene Oxide Composite for Syringe-Push Protein Absorption Membrane

The adsorption of proteins on membranes has been used for simple, low-cost, and minimal sample handling of large volume, low protein abundance liquid samples. Syringe-push membrane absorption (SPMA) is an innovative way to process bio-fluid samples by combining a medical syringe and protein-absorbable membrane, which makes SPMA a simple, rapid protein and proteomic analysis method. However, the membrane used for SPMA is only limited to commercially available protein-absorbable membrane options. To raise the method’s efficiency, higher protein binding capacity with a lower back pressure membrane is needed. In this research, we fabricated electrospun polybutylene succinate (PBS) membrane and compared it to electrospun polyvinylidene fluoride (PVDF). Rolling electrospinning (RE) and non-rolling electrospinning (NRE) were employed to synthesize polymer fibers, resulting in the different characteristics of mechanical and morphological properties. Adding graphene oxide (GO) composite does not affect their mechanical properties; however, electrospun PBS membrane can be applied as a filter membrane and has a higher pore area than electrospun PVDF membrane. Albumin solution filtration was performed using all the electrospun filter membranes by the SPMA technique to measure the protein capture efficiency and staining of the protein on the membranes, and these membranes were compared to the commercial filter membranes—PVDF, nitrocellulose, and Whatman no. 1. A combination of rolling electrospinning with graphene oxide composite and PBS resulted in two times more captured protein when compared to commercial membrane filtration and more than sixfold protein binding than non-composite polymer. The protein staining results further confirmed the enhancement of the protein binding property, showing more intense stained color in compositing polymer with GO.

Enhancing the efficiency of disc membrane chromatography modules by using a flow directing layer

Disc membrane chromatography modules are widely used for laboratory-scale protein separations. These have high radial to axial aspect ratios, with the inlet and the outlet being located at the centre. This results in a huge variability in flow path lengths. Also, the radial velocity in the feed side header decreases very significantly in an outward direction, while that in the permeate side header increases in an inward direction. Therefore, the flow paths closer to the axis of the membrane disc have higher average velocity compared to those closer to the periphery. Consequently, the solute residence time distribution within the disc membrane chromatography module is very large, which results in broad flow-through and eluted peaks and early breakthrough of bound solutes. In this paper, we discuss a simple but effective solution to this problem which involves the incorporation of a flow directing layer (FDL) within the membrane module. The FDL could be placed either in the front or at the rear of the membrane disc. The presence of FDL results in equalization of path lengths within the module, leading to narrowing of residence time distribution, and thereby improvement in separation efficiency. Modules housing strong cation exchange membrane discs having two different bed volumes of 0.4 mL (40 mm diameter) and 4.7 mL (60 mm diameter) were designed and fabricated in-house. The impact of using FDL on both the front side (F-FDL) and the rear side (R-FDL) was investigated. The separation efficiency of the membrane modules was assessed using salt tracer experiments, breakthrough protein binding, and ternary protein separation carried out in the bind-and-elute mode. The results confirmed that the use of the FDL significantly enhanced the separation efficiency. In addition to membrane chromatography, this approach of using an FDL could be extended to other membrane disc based modules such as in-line and syringe filters and membrane reactors.

Use of syringe filters to isolate Campylobacter species from stool samples

We investigated the efficacy of syringe filters and membrane filters with different pore sizes for recovering Campylobacter. A syringe filter with a 0.45 μm pore size achieved the highest recovery rate (0.29%), while polycarbonate membrane filters with pore sizes of 0.6 μm and 0.4 μm recovered less Campylobacter, at 0.01% and 1.3 × 10−3%, respectively. We also tested 601 diarrheic stool samples using membrane and syringe filtration methods. A total of 23 Campylobacter jejuni/coli were isolated from both syringe and membrane filtration; nine and one were isolated from only syringe or only membrane filtration, respectively (p < .05). The syringe filtration technique was better than membrane filtration for the isolation of Campylobacter.

In-syringe solvent-assisted dispersive solid phase extraction followed by flame atomic absorption spectrometry for determination of nickel in water and food samples

This study presents a new in-syringe solvent-assisted dispersive solid phase extraction (ISSADSPE) method for determination of nickel ions in water and food. The method involved dispersion of a few milligrams of sorbent in the sample solution inside the barrel of a syringe through application of a disperser solvent. In less than 1 min, the extraction equilibrium was achieved due to dispersion of the sorbent and high mass transfer rate. Afterwards, syringe membrane was employed to separate the dispersed sorbent from the solution. Then the ethanol was withdrawn by syringe membrane to dissolve the analyte-enriched sorbent. Flame atomic absorption spectroscopy was applied to assess the obtained extract. Effective factors such as the sorbent nature and amount, sample volume, pH, ligand concentration, type and volume of disperser solvent and eluent, ionic strength and extraction time were evaluated and optimized to improve the extraction efficiency. Under optimized conditions (pH = 8.0, ligand concentration = 2.0 × 10−4, sorbent = 10 mg of benzophenone, disperser solvent 500 μL of ethanol), the limit of detection and quantification were found to be 0.7 μg L−1 and 2.0 μg L−1, respectively. The calibration curve kept its linearity from 2 to150 μg L−1, with the square correlation coefficient of 0.997. The relative standard deviation was measured as 2.5% while the enrichment factor was assessed as 50. The proposed method was successfully applied for determination of nickel in environmental water, spinach and celery samples, with recovery range of 97–101%.

Syringe-push membrane absorption as a simple rapid method of urine preparation for clinical proteomics.

BackgroundThe analysis of urinary proteome might reveal biomarkers of clinical value. However, current methods of urine preparation for down-stream proteomic analysis are complicated, time-consuming, and/or expensive. This study aims to develop a robust, simple, inexpensive and readily accessible urine preparation method to facilitate clinical proteomic workflow.ResultSyringe-push membrane absorption (SPMA) was successfully developed by a combination of 5-ml medical syringe and protein-absorbable membrane. Comparing three membranes i.e., nitrocellulose, polyvinylidene difluoride (PVDF) and Whatman no.1, nitrocellulose combined with SPMA (nitrocellulose-SPMA) provided the greatest quality of proteome profile as demonstrated by 2-DE. The quality of the proteome profile and the performance of nitrocellulose-SPMA were systematically compared with three current methods of urine preparation (i.e., ultrafiltration, dialysis/lyophilization and precipitation). While different methods of urine preparation provided comparable proteome quality, nitrocellulose-SPMA had better working performance due to acceptable recovery yield, less workload, short working time, high accessibility and low unit cost. In addition, protein absorbed on nitrocellulose harvested from the SPMA procedure could be stored as a dried membrane at room temperature for at least 1-month without protein degradation or modification.ConclusionsSPMA is a simple rapid method of preparing urine for downstream proteomic analysis. Because of it is highly accessible and has long storage duration, this technique holds potential benefit for large-scale multi-center research and future development of clinical investigation based upon urinary proteomic analysis.Electronic supplementary materialThe online version of this article (doi:10.1186/s12014-015-9087-4) contains supplementary material, which is available to authorized users.

Determination of Dicyandiamide in Milk Powder by Ion Exclusion Chromatography

A method for determination of dicyandiamide in milk powder by ion exclusion chromatography-UV detection( IEC-UV) was developed and was verified by ion chromatography-mass spectrometry( IC-MS).Sample was extracted with water( solid-liquid ratio of 1∶ 2) and acetonitrile( solid-liquid ratio of 1∶ 8) with shaking. After centrifuging for 20 min at 10000 r / min,the supertant was filtered through a 0. 22-μm syringe membrane filter and then injected into chromatograph. The chromatographic separation of dicyandiamide was performed on an IonPac: emoji: ICE-AS1 column( 250 mm × 9 mm,5 μm). The mobile phase was the mixture of 3 mmol / L formic acid and acetonitrile at the ratio of 3∶ 2 with a flow rate of 0. 8 mL / min. The detection wavelength was set at 220 nm,and the column temperature was maintained at 30 ℃. The results showed that the calibration curve of dicyandiamide was linear in the range of 50 μg / L-0. 3 g / L with a correlation coefficient of 0. 9999. The limit of detection,based on a signal-to-noise ratio of 3 ∶ 1,was12. 5 μg / L. The average recoveries were in the rang of 97. 6%-100% with the spiked levels at 500 ng / g,0. 5 mg / g and 3. 6 mg / g,respectively,and the relative standard deviation was 0. 8%.

Automated indirect fluoride determination by ICP-OES using discontinuous-flow analysis

An automated method for the indirect determination of fluoride by inductively coupled plasma atomic emission spectrometry using discontinuous-flow analysis has been developed. A modified flow injection analysis system was used for sample preparation. The method is based on the determination of excess cerium(III) ion after precipitation of CeF3. Separation of the precipitate is performed online on a syringe membrane filter that is cleaned each analysis cycle by 1 M nitric acid, ensuring a long life-time for the filter. As a result of the short reaction time, a detection limit of 9.5 mg L−1 was obtained. The precision (RSD) of the proposed method is 1.02% at fluoride concentration of 28 mg L−1. The applicability of the technique for groundwater monitoring of fluoride-contaminated area is demonstrated.

Hydraulic permeability of a hydrogel‐based contact lens membrane for low flow rates

AbstractHydrogels, widely used for contact lenses, are a class of materials that consists of both fluid and solid components. The aqueous fluid phase is supported by a solid polymer matrix. In this study, we characterize the water transport characteristics of an Etafilcon‐A (copolymer of 2‐hydroxyethyl methacrylate and methacrylic acid) membrane. A flow rate‐controlled permeameter consisting of a syringe pump, membrane holder, pressure transducer, and tubing was developed and used to measure the pressure drop across a flat membrane (average thickness ∼ 686 μm ± 40). The relation between velocity and pressure drop was measured. These data were fit to rigid media and biphasic models of 1‐D flow to determine hydraulic permeability, k = 1.80 × 10−14 m4/N s. The results provide insight into the fluid flow properties of this hydrogel under low flow and low pressure conditions (&lt;3 kPa). Physiological implications of these measured parameters on flow and deformation across the lens due to blinking are discussed. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 3730–3735, 2007

Syringeal muscles fit the trill in ring doves (Streptopelia risoriaL.)

In contrast to human phonation, the virtuoso vocalizations of most birds are modulated at the level of the sound generator, the syrinx. We address the hypothesis that syringeal muscles are physiologically capable of controlling the sound-generating syringeal membranes in the ring dove (Streptopelia risoria) syrinx. We establish the role of the tracheolateralis muscle and propose a new function for the sternotrachealis muscle. The tracheolateralis and sternotrachealis muscles have an antagonistic mechanical effect on the syringeal aperture. Here, we show that both syringeal muscles can dynamically control the full syringeal aperture. The tracheolateralis muscle is thought to directly alter position and tension of the vibrating syringeal membranes that determine the gating and the frequency of sound elements. Our measurements of the muscle's contractile properties, combined with existing electromyographic and endoscopic evidence, establish its modulating role during the dove's trill. The muscle delivers the highest power output at cycle frequencies that closely match the repetition rates of the fastest sound elements in the coo. We show that the two syringeal muscles share nearly identical contraction characteristics, and that sternotrachealis activity does not clearly modulate during the rapid trill. We propose that the sternotrachealis muscle acts as a damper that stabilizes longitudinal movements of the sound-generating system induced by tracheolateralis muscle contraction. The extreme performance of both syringeal muscles implies that they play an important role in fine-tuning membrane position and tension, which determines the quality of the sound for a conspecific mate.

Producing song: the vocal apparatus.

In order to achieve the goal of understanding the neurobiology of birdsong, it is necessary to understand the peripheral mechanisms by which song is produced. This paper reviews recent advances in the understanding of syringeal and respiratory motor control and how birds utilize these systems to create their species-typical sounds. Songbirds have a relatively homogeneous duplex vocal organ in which sound is generated by oscillation of a pair of thickened labia on either side of the syrinx. Multiple pairs of syringeal muscles provide flexible, independent control of sound frequency and amplitude, and each side of the syrinx exhibits a degree of acoustic specialization. This is in contrast to many non-songbirds, including vocal learners such as parrots, which have fewer syringeal muscles and use syringeal membranes to generate sound. In doves, at least, these membranes generate a harmonic signal in which the fundamental frequency is regulated by respiratory pressure in the air sac surrounding the syrinx and the overtones are filtered out by the vocal tract. The songs of adult songbirds are generally accompanied by precisely coordinated respiratory and syringeal motor patterns that, despite their relative stereotypy, are modulated in real time by somatosensory feedback. Comparative studies indicate songbirds have evolved species-specific motor patterns that utilize the two sides of the syrinx in specific ways and enhance the particular acoustic effects characterizing the species song. A vocal mimic tutored with heterospecific song uses the same motor pattern as the tutor species when he accurately copies the song, suggesting that physical or physiological constraints on sound production have had a prominent role in the evolution of species-specific motor patterns. An understanding of the relationship between the central processing and peripheral performance of song motor programs is essential for an understanding of the development, function, and evolution of these complex vocal signals.

Sound production in the collared dove: a test of the 'whistle' hypothesis

The mechanism of sound production in the collared dove Streptopelia decaocto was studied to test the validity of the 'whistle' model and to analyze the role of vocal tract resonances. In this study, the vocalizations of six male adult doves were recorded both in normal air and in a mixture of 80 % helium and 20 % oxygen (heliox). Depending on the way in which the syrinx operates, the spectral structure of the vocalizations is expected to show specific changes in heliox. The effects of heliox differed substantially depending on the type of vocal element. Except for a significant decrease in amplitude, unmodulated elements, i.e. elements with a constant frequency, were relatively unaffected by heliox. In contrast, modulated elements, i.e. elements with an abrupt increase in frequency, showed a gradual increase in frequency with increasing helium concentration. This specific increase in frequency stopped when the modulation frequency was 1.5 times the base frequency, even when the helium concentration was increased further. In some individuals, a frequency band of half the base frequency was also observed. In general, the proportion of modulated elements also showed a significant decrease. The lack of change in the fundamental frequency of the unmodulated elements and in the base frequency of the modulated elements indicates that these vocalizations are not produced like a whistle. It is more likely that they are the result of vibration of the syringeal membranes. Generally, vocal tract resonances do not play an active role in the modification of vocalizations, although they might enhance the fundamental frequency passively. The results suggest that the almost pure tonal vocalizations are produced as such in the syrinx and undergo limited modification when passing through the vocal tract. The effect of heliox on the modulation frequency suggests (1) that different sound-producing mechanisms may underlie different types of vocalizations, and (2) that resonance properties of the vocal system may be involved in the production or modification of the modulation frequency.

Mechanisms of vocal production in budgerigars (Melopsittacus undulatus).

Songbirds vocalizing in helium show a change in the spectral quality of their vocalizations. This effect is due to an increase in the speed of sound in helium that in turn alters the resonance properties of the vocal tract. Here, this approach is extended to a psittacine, the budgerigar (Melopsittacus undulatus), whose syringeal anatomy and innervation differ from that of a songbird. Contact calls from birds vocalizing in heliox (70/30 helium/oxygen environment) showed an overall increase in the amount of energy at frequencies above the fundamental, slight changes in the frequency of the fundamental and harmonics, and some change in the level of harmonics. Calls produced by a syringeally denervated bird showed more dramatic changes. Recordings from live birds were compared with sounds produced by various simple "artificial" tracheal and syringeal models. Results suggest that budgerigars produce contact calls using the syringeal membranes as a unitary sound source which produces acoustic energy in a narrow frequency band whose fundamental frequency is matched to the resonant frequency of the trachea. The syrinx is not normally coupled to the tracheal resonator, and resonances probably play only a minor role in shaping the spectrum of contact calls.

Fundamental study of androgenic dysphonia in the female chicken organic changes in the syringeal membranes visualized with SEM

Fundamental study of androgenic dysphonia in the female chicken organic changes in the syringeal membranes visualized with SEM

The ultrastructure of the syringeal membranes in the chicken

The phonatory organ in the chicken is the syrinx, which is located at the carina. Phonation is induced through the vibration of the lateral and medial syringeal membranes in the syrinx. There are very few reports on the ultrastructure of the chicken syrinx.The ultrastructure of the medial and lateral syringeal membranes was observed by scanning electron microscopy in the female chickens two or three months after hatching.The surface of the syringeal membrane consisted of squamous epithelium in the center and ciliated epithelium at the margins. The space between the center and the margin consisted of squamous epithelium and ciliated epithelium.The syringeal membrane consisted of three layers: the epithelium, superficial layer of the lamina propria, and deep layer of the lamina propria. The superficial layer of the lamina propria, revealed a network of collagenous and elastic fibers, with collagenous fibers forming a bundle in the deep layer.In the vibrating syringeal membrane, the deep layer, and the epithelium and superficial layer are considered to work a body and a cover, respectively.

Mechanisms of sonar pulse production by oilbirds

The echolocating clicks of oilbirds (Steatornis caripensis) are generated in two bronchial semisyringes. Each click has a duration of 20 to 60 ms and may consist of a continuous broadband sound or be divided by a short silent interval into two shorter sounds. Electromyograms, together with measurements of subsyringeal pressure, tracheal pressure, and the rate of tracheal airflow, show that clicks are preceded by contraction of the sternotrachealis muscles which move the syrinx caudad, causing adduction of the syringeal membranes during expiratory airflow and initiating phonation. Subsequent contraction of a previously undescribed syringeal muscle terminates the click by rotating a syringeal cartilage and abducting the external tympaniform membranes. This syringeal muscle does not contract during longer duration vocalizations. It is thus specialized for the production of clicklike sounds. Simultaneous measurement of the rate of airflow through each semisyrinx indicates that during some clicks one semisyrinx closes while the other remains open. This is the first evidence that airflow through each side of the syrinx can be independently controlled during pronation. [Work supported by NSF.]

Mechanism for the production of echolocating clicks by the grey swiftlet,Collocalia spodiopygia

1. Orientation sounds of the echolocating swiftlet,Collocalia spodiopygia (family Apodidae) consist of two clicks, each having a duration of a few milliseconds, separated from each other by a silent interval lasting about 20 ms (Fig. 1). Most of the acoustic energy is between 2 and 8 kHz. 2. These clicks are generated in the syrinx and require syringeal airflow. 3. The first member of the double click is initiated by contraction of the sternotrachealis muscles (Fig. 3) which reduces tension on the syrinx by pulling the trachea caudad (Fig. 2). This causes the first bronchial ring to rotate inward (Fig. 10), reducing the syringeal aperture. As the external tympaniform membrane approaches the internal tympaniform membrane, the subsyringeal (= sternal air sac) pressure rises with increasing syringeal resistance and expiratory tracheal airflow peaks at about 6.1 ml/s (Figs. 6, 7, Table 1). Bernoulli forces cause the internal tympaniform membranes to vibrate, producing the first member of the double click (Fig. 9b). 4. The syrinx is closed during the silent intraclick interval by apposition of the syringeal membranes (Figs. 9c, 10). Subsyringeal pressure peaks at about 17cm H2O during this interval (Fig. 6), which is terminated by contraction of the tracheolateralis muscles (Fig. 3) that moves the syrinx craniad and causes the first bronchial ring to rotate outward, thus abducting the external tympaniform membranes and opening the syringeal lumen (Fig. 9d). 5. The second member of the double click occurs as the internal and external tympaniform membranes begin to separate, allowing expiratory airflow to resume (Fig. 9d). Tracheal airflow peaks at about 10 ml/s during this click as syringeal resistance and subsyringeal pressure drop (Figs. 6, 7, Table 1). The second click is terminated by further abduction of the external tympaniform membranes to their resting position (Fig. 9a). 6. The ability of swiftlets to transform a longer duration squeak-like vocalization into two brief clicks by momentarily closing the syrinx probably represents an important adaptation for acoustic orientation. By generating brief clicks they have created a sonar signal with a greater bandwidth and having abrupt rise-decay times that should improve target range determination based on measurement of the pulse-echo interval.