Sample Flow Rate Research Articles

Real-time monitoring of aqueous total N-nitrosamines by UV photolysis and chemiluminescence.

N-nitrosamines such as N-nitrosodimethylamine (NDMA), N-nitrosodiethylamine (NDEA), N-nitrosopiperidine (NPIP), and N-nitrosopyrrolidine (NPYR) have been established as potent carcinogens that can induce diverse types of cancer. Several studies have extensively investigated the accurate quantification of total N-nitrosamines (TONO) and the intricate nature of the matrix in which they are detected. The potential for the formation of N-nitrosamines in post-combustion CO2 capture (PCCC) and water treatment has raised concerns. This study outlines a unique method for the quantification of TONO in aqueous matrices using UV photolysis and the subsequent detection of NO by chemiluminescence. This method offers benefits such as operation in the continuous mode and handling of high sample flow rates to achieve a low limit of detection (LOD) and a low limit of quantification (LOQ). The observed LODs for the individual N-nitrosamines of NDMA, N-nitrosomorpholine (NMOR), N-nitrosodibutylamine (NDBA), and NPIP range between 0.06 and 0.2µM at a sample flow rate of 0.25mL/min, while the LOD range is reduced to between 0.02 and 0.06µM at 0.75mL/min. Linear responses for the NO produced from specific N-nitrosamines are observed between 0.5 and 10µM. The developed method is resistant to interfering chemicals (i.e., nitrite, amines, and carbonyls) and exhibits high specificity.

Determination of Nitrobenzenes in Air by a Needle Trap Device (NTD) and Gas Chromatography-Mass Spectrometry (GC-MS)

A simple needle-trap device (NTD) coupled with gas chromatography-mass spectrometry (GC-MS) was developed to determine trace levels of nitrobenzenes (NBs) in workplace air. The NTD with sorbent inside the needle was employed for the quantification of nitrobenzene, o-nitrotoluene, m-nitrotoluene, p-nitrotoluene, o-nitrochlorobenzene, m-nitrochlorobenzene, and p-nitrochlorobenzene. The optimum temperature and time for desorption of analytes were 270 °C and 4 min, and parameters such as sampling flow rate, breakthrough volume, and storage capability were also optimized. The limits of detection and quantification were in the ranges of 1.8 × 10−4–1.1 × 10−3 and 5.9 × 10−4–3.6 × 10−3 mg m−3, respectively. The developed protocol was successfully applied for the determination of NBs in vehicle repair plants where the highest detected concentration was 0.11 mg m−3. The established NTD-GC-MS generally applies to monitoring trace levels of NBs in the air.

Sensitive Determination of Hydrochlorothiazide Drug in the Various Samples Via Developed Method of CFIA System

تحديد عقار هايدروكلوروثيازايد في العينات الصيدلانية والبايولوجية الادرار باستخدام تقنية جديدة لتحليل الحقن الجرياني المستمر وهي سريعة , بسيطة ,اقتصادية وحساسة. المعقد المتكون بواسطة تفاعل هيدروكلوروثيازايد مع اورثوفانيلين داي امين مع فيروسيانيد البوتاسيوم لانتاج ناتج ملون برتقالي عند طول موجي 480 نانومتر كان الاساس للطريقة المطورة . العوامل الكيميائية و الفيزيائية الاخرى التي لها تؤثر على استقرارية وتطور الناتج الملون المستخدم في هذه الطريقة المطورة تضمنت حجم العينة,معدل التدفق,تركيز الكاشف وملف التفاعل ,خطية الطريقة المقترحة كانت 5-150 مايكروغرام .مل-1 ومعامل الارتباط كان0.9988 و كانت قيم النسبة المئوية للأسترداد والخطاء النسبي٪100.88, 0.88 على التوالي .قيم حد الكشف والحد الكمي 2.622,7.97 . نمذجة العينة 90 نموذج لكل ساعة تم استخدام النهج الجديد بشكل فعال لتحديد الهايدروكلورثيازايد في العينات النقية ,البايولوجية وا لصيدلانية

An Integrated Inertial-Magnetophoresis Microfluidic Chip Online-Coupled with ICP-MS for Rapid Separation and Precise Detection of Circulating Tumor Cells.

Circulating tumor cells (CTCs) are recognized as promising targets for liquid biopsy, which play an important role in early diagnosis and efficacy monitoring of cancer. However, due to the extreme scarcity of CTCs and partial size overlap between CTCs and white blood cells (WBCs), the separation and detection of CTCs from blood remain a big challenge. To address this issue, we fabricated a microfluidic chip by integrating a passive contraction-expansion array (CEA) inertial sorting zone and an active magnetophoresis zone with the trapezoidal groove and online coupled it with inductively coupled plasma mass spectrometry (ICP-MS) for rapid separation and precise detection of MCF-7 cells (as a model CTC) in blood samples. In the integrated microfluidic chip, most of the small-sized WBCs can be rapidly removed in the circular CEA inertial sorter, while the rest of the magnetically labeled WBCs can be further captured in the trapezoidal groove under the magnetic field. As a result, the rapid separation of MCF-7 cells from blood samples was achieved with an average recovery of 91.6% at a sample flow rate of 200 μL min-1. The developed online integrated inertial-magnetophoresis microfluidic chip-ICP-MS system has been applied for the detection of CTCs in real clinical blood samples with a fast analysis speed (5 min per 1 mL blood). CTCs were detected in all 24 blood samples from patients with different types of cancer, exhibiting excellent application potential in clinical diagnosis.

A high-throughput, turbulent-mixing, condensation aerosol concentrator for direct aerosol collection as a liquid suspension

Trace measurement of aerosol chemical composition in workplace atmospheres requires the development of high-throughput aerosol collectors that are compact, hand-portable, and can be operated using personal pumps. We describe the design and characterization of a compact, high flow, Turbulent-mixing Condensation Aerosol-in-Liquid Concentrator (TCALC) that allows direct collection of aerosols as liquid suspensions, for off-line chemical, biological, or microscopy analysis. The TCALC unit, measuring approximately 12 × 16 × 18 cm, operates at an aerosol sample flowrate of up to 10 L min−1, using rapid mixing of a hot flow saturated with water vapor and a cold aerosol sample flow, thereby promoting condensational growth of aerosol particles. We investigated the effect of operating parameters such as vapor temperature, growth tube wall temperature, and aerosol sample flowrate, along with the effect of particle diameter, inlet humidity, aerosol concentration, and operation time on TCALC performance. Nanoparticles with an initial aerodynamic diameter ≥25 nm could grow to droplet diameters >1400 nm with an efficiency ≥80%. Good droplet growth efficiency was achieved for sampled aerosol relative humidity ≥9%. We measured complete aerosol collection for concentrations of ≤3 × 105 cm−3. The results showed good agreement between the particulate mass collected through the liquid collector and direct filter collection. The TCALC eliminates the need for sample preparation and filter digestion during chemical analysis, thereby increasing sample recovery and substantially improving the limit of detection and sensitivity of off-line trace analysis of collected liquid samples.

A novel magnetized bio-solid phase extractor for the preconcentrations of Hg(II), Ni(II) and Zn(II) from foods

Herein, Agaricus augustus, a mushroom, loaded on γ-Fe2O3 magnetic nanoparticles was developed as a biosorbent for the simultaneous preconcentrations of trace levels of Hg(II), Ni(II), and Zn(II)) in tap water, beverages, and some food samples prior to their determination by inductively coupled plasma optical emission spectrometry (ICP-OES). The experimental factors affecting the extraction performance were carefully examined throughout the investigation. The best experimental conditions were determined as pH 4.0, 3 mL/min of sample flow rate, 75 mg of biosorbent, 100 mg of γ-Fe2O3 magnetic nanoparticles, and 500 mL of sample volume. LOD values were determined as 0.016, 0.011, and 0.023 ng/mL, respectively for Hg(II), Ni(II), and Zn(II). The biosorption capacities were determined as 47.2 mg/g for Hg(II), 51.5 mg/g for Ni(II), and 49.0 mg/g for Zn(II). The effectiveness of the recommended method was assessed using certified reference material.

Pb(II) solid-phase extraction in wastewater samples prior to flame atomic absorption spectrometry analysis using chitosan and alginate modified carbon

ABSTRACT The sustainability concept was kept in view by designing and synthesising a novel adsorbent for Pb(II) ion, using natural and metal-free precursors which are renewable and biodegradable, i.e. alginate, chitosan, and carbon. The study was aimed to introduce the synthesis of Carbon/Alginate/Chitosan composite (CAC) as a beneficial adsorbent tailored for the solid-phase extraction (SPE) of Pb(II) prior to its analysis via flame atomic absorption spectrometry (FAAS). The successful preparation of the CAC material is elucidated, characterised through FTIR for functional group analysis, and evaluated for surface morphology and elemental composition via SEM-EDX. Optimisation of SPE parameters was carefully conducted to enhance adsorption-desorption efficiency across diverse conditions. These optimised factors were a pH level of 6, initial Pb(II) concentration of 20 mg/L, sample flow rate 5 mL/min, elution utilising Na2EDTA at a rate of 5 mL/min, sample volume of 20 mL, Na2EDTA eluent volume of 10 mL, and Na eluent concentration of 0.5 M. Application of CAC-based SPE for Pb(II) analysis in wastewater samples under these optimised conditions yielded exceptional recovery rates of 93–96%, with a limit of detection (LoD) value of 71.4 µg/L. Moreover, a notable preconcentration factor of 4–8 times is achieved for Pb(II) in wastewater samples, facilitating the detection of Pb(II) concentrations as low as 30 µg/L.

A porous composite sorbent incorporating a metal organic framework and zinc oxide in cryogel to extract carbamate pesticides

A composite sorbent was designed and fabricated by incorporating the Materials of Institute Lavoisier (MIL-101) and zinc oxide (ZnO) into polyvinyl alcohol (PVA) cryogel. The composite sorbent was produced to extract carbamates (carbofuran, carbaryl, isoprocarb and diethofencarb) by in-syringe solid phase extraction (SPE). MIL-101 and ZnO enhanced the adsorption of the carbamates by creating π-π stacking and hydrogen bonding, while porous PVA cryogel acted as a solid support which helped to reduce backpressure in the system. The extraction of the target carbamates was optimized by varying the amount of MIL-101 and ZnO used in the sorbent fabrication, desorption conditions, sample pH, ionic strength, sample flow rate and sample volume. The extracted target carbamates were quantitatively determined using high performance liquid chromatography technique. The developed method exhibited linearity from 1.0 to 150.0 μgL−1 for all four target carbamate pesticides with a limit of detection 0.3 µg/L. The method identified carbamates in fruit juice and white wine, obtaining recoveries from 78.1 to 108.2 % and the relative standard deviation (RSD) lower than 6.3 %. The developed composite sorbent showed good accuracy, is simple to fabricate, works rapidly and can be used for 17 extraction-regeneration cycles.

Compact, high-flow, water-based, turbulent-mixing, condensation aerosol concentrator for collection of spot samples.

A new high-flow, compact aerosol concentrator, using rapid, turbulent mixing to grow aerosol particles into droplets for dry spot sample collection, has been designed and tested. The "TCAC (Turbulent-mixing, Condensation Aerosol Concentrator)" is composed of a saturator for generating hot vapor, a mixing section where the hot vapor mixes with the cold aerosol flow, a growth tube where condensational droplet growth primarily occurs, and a converging nozzle that focuses the droplets into a beam. The prototype concentrator utilizes an aerosol sample flow rate of 4 L min-1. The TCAC was optimized by varying the operating conditions, such as relative humidity of the aerosol flow, mixing flow ratio, vapor temperature, and impaction characteristics. The results showed that particles with a diameter ≥ 25 nm can be grown to a droplet diameter > 1400 nm with near 100% efficiency. Complete activation and growth were observed at relative humidity ≥ 25% of the aerosol sample flow. A consistent spot sample with a diameter of (the diameter of a circle containing 90% of the deposited particles) was obtained regardless of the aerosol particle diameter ( ). For fiber counting applications using phase contrast microscopy, the TCAC can reduce the sampling time, or counting uncertainty, by two to three orders of magnitude, compared to the 25-mm-filter collection. The study shows that the proposed mixing-flow scheme enables a compact spot sample collector suitable for handheld or portable applications, while still allowing for high flow rates.

Harnessing an amide-based covalent organic framework in solid-phase extraction for chlorophenol analysis in industrial wastewaters.

An amide-based covalent organic framework (COF) was successfully synthesized using the reaction between 1,3,5-trimesoyl chloride and ethylenediamine. The structure and morphology of the COF were characterized using Fourier-transform infrared spectra, nuclear magnetic resonance spectroscopy, X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and Brunauer-Emmett-Teller surface area analysis. The COF was employed as a solid-phase extraction adsorbent for the sampling and preconcentration of chlorophenols from industrial wastewater samples prior to high-performance liquid chromatography with ultraviolet detection. The experimental parameters influencing the extraction efficiency including type and volume of eluent solvent, sample solution volume, salt concentration, sample flow rate, and sample solution pH were investigated and optimized using a response surface methodology employing Box-Behnken-design. Under optimized conditions, calibration curves exhibited good linearities over the range of 0.003-10µg/mL with determination coefficients (R2) ranging from 0.9982 to 0.9999. The method's limits of detection ranged from 0.001 to 0.01µg/mL. Good repeatability was achieved with relative standard deviations below 4.7%. The developed procedure utilizing the COF adsorbent was successfully applied to determine chlorophenols accurately and precisely in various industrial wastewater samples.

Online monitoring system for qualitative and quantitative analysis of bioaerosols by combined ATP bioluminescence assay with loop-mediated isothermal amplification

Rapid detection of airborne pathogens is crucial in preventing respiratory infections and allergies. However, technologies aiming to real-time analysis of microorganisms in air remain limited due to the sparse and complex nature of bioaerosols. Here, we introduced an online bioaerosol monitoring system (OBMS) comprised of integrated units including a rotatable stainless-steel sintered filter-based sampler, a lysis unit for extracting adenosine triphosphate (ATP), and a single photon detector-based fluorescence unit. Through optimization of the ATP bioluminescence method and establishment of standard curves between relative luminescence units (RLUs) and ATP as well as microbial concentration, we achieved simultaneous detection of bioaerosols' concentration and activity. Testing OBMS with four bacterial and two fungal aerosols at a sampling flow rate of 10 to 50 L/min revealed an outstanding collection efficiency of 95 % at 30 L/min. A single OBMS measurement takes only 8 min (sampling: 5 min; lysis and detection: 3 min) with detection limits of 3 Pcs/ms photons (2.9 × 103 and 292 CFU/m3 for Staphylococcus aureus and Candida albicans aerosol). In both laboratory and field tests, OBMS detected higher concentrations of bioaerosol compared to the traditional Andersen impactor and liquid biosampler. When combined OBMS with loop-mediated isothermal amplification (LAMP), the bioaerosol can be qualitative and quantitative analyzed within 40 min without the cumbersome procedures of sample pretreatment and DNA extraction. These results offer a high compressive and humidity resistance membrane filtration sampler and validate the potential of OBMS for online measurement of bioaerosol concentration and composition.

Simultaneous multiple target detection platform based on vertical flow immunoassay

In general, vertical flow assay (VFA) has a disadvantage of requiring a complex analysis process that involves manually injecting various reagents (target analyte, washing buffer, detection conjugate, etc.) sequentially. However, in this study, we have developed an innovative paper-based VFA device that replaces the complex analysis process with one-step and enables the detection of multiple targets. The fabrication process of the multi-target detection VFA device is as follows: preparation and pre-treatment of the strip materials, design of strip cartridge, design of the multiple detection VFA device, optimization experiments for strip sample flow rates, determination of device analysis time, determination of device limit of detection (LOD), multiple target signal uniformity experiment, immunoglobulin G (IgG) and C-reactive protein (CRP) antigen-antibody multiple detection experiment, and data extraction and analysis method. The use of paper-based materials enables the device to be produced at cost-effective, and cartridge production allowed for uniform array formation. IgG and CRP are used to evaluate the performance of the device as common biomarkers. The device proposed in this study is currently under research. To validate multiple target detection capability of the VFA device proposed in this study, two types of antigens-antibodies (Human IgG and Human CRP) were employed. The detection limit is 0.15 μg/mL for IgG and 0.19 μg/mL for CRP in naked eye. Furthermore, it was confirmed that there is no cross-reactivity caused by the device structure through IgG and CRP antigens. In conclusion, the VFA device proposed in this study consists of a one-step analysis process, and it has been confirmed that it can detect multiple targets simultaneously.

Affinity Purification of a 6X-His-Tagged Protein using a Fast Protein Liquid Chromatography System.

Functional characterization of proteins requires them to be expressed and purified in substantial amounts with high purity to perform biochemical assays. The Fast Protein Liquid Chromatography (FPLC) system allows high-resolution separation of complex protein mixtures. By adjusting various parameters in FPLC, such as selecting the appropriate purification matrix, regulating the protein sample's temperature, and managing the sample's flow rate onto the matrix and the elution rate, it is possible to ensure the protein's stability and functionality. In this protocol, we will demonstrate the versatility of the FPLC system to purify 6X-His-tagged flap endonuclease 1 (FEN1) protein, produced in bacterial cultures. To improve protein purification efficiency, we will focus on multiple considerations, including proper column packing and preparation, sample injection using a sample loop, flow rate of sample application to the column, and sample elution parameters. Finally, the chromatogram will be analyzed to identify fractions containing high yields of protein and considerations for proper recombinant protein long-term storage. Optimizing protein purification methods is crucial for improving the precision and reliability of protein analysis.

Compact colorimetric method for determining formaldehyde in indoor air: Applying to an environment contaminated with hand sanitizer vapor

Hand sanitizer, widely used during the COVID-19 pandemic, must contain at least 60 % ethyl alcohol (ethanol) as an active ingredient. Due to its high vapor pressure, ethanol is rapidly transformed into vapor after the application over any surface. However, depending on the indoor air conditions, ethanol can rapidly oxidize to formaldehyde near harmful concentration levels. This study describes a simple and sensitive method to determine parts-per-billion (ppb) of gaseous formaldehyde using a cuvette (1.5 mL polystyrene, path length: 10 mm) as a microimpinger. Indoor and outdoor air was collected by the microimpinger containing 500 μL of 3-Methyl-2-benzothiazolinone hydrazone (MBTH) (2.32 × 10−3 mol L−1) at 50 mL min−1, resulting in a blue product after 30 min of sampling. Absorbance was measured at 680 nm and is proportional to the sampling period, analyte concentration, and sampling flow rate. Under the established conditions, a limit of detection of 7.0 ppb was achieved, which can be improved using longer sampling times. The analytical method was used to evaluate the oxidation of ethanol vapor by ozone in the indoor air. 10 min after the application of hand sanitizer, the air sample taken over the next 30 min revealed a notable rise in the concentration of low molecular weight aldehydes, measured as formaldehyde equivalent, within the room's air, and can reach around 100 ppb, which may be responsible for effects such as watery eyes, burning sensations in the mucous membrane, and difficulty breathing. The present technique affords a simple, inexpensive measurement with very little reagent consumption. Besides, the method is selective and highly sensitive. This method could be used either in outdoor or indoor environments.

Optically induced dielectrophoresis for continuous separation and purification of C. vulgaris and H. pluvialis

Marine microalgae are widely present in the natural environment, exhibiting a significant economic value. However, during the inoculation and cultivation process of microalgae, the introduction of unwanted algae is bound to trigger nutrient competition, leading to a decrease in the growth rate of microalgae and consequently impacting their economic value in production. To address this issue, this study integrates the optically induced dielectrophoresis (ODEP) manipulation technology based on the continuous flow in a microfluidic system. A two-stage cell filter, utilizing two virtual optical spots, is designed and manufactured. Leveraging the size differences between microalgae, continuous separation and purification of mixed samples containing Chlorella vulgaris and Haematococcus pluvialis are achieved within microchannels. Additionally, optimal ODEP manipulation conditions for mixed algal liquid samples, comprising C. vulgaris and H. pluvialis, are demonstrated, including appropriate alternating current voltage (6 V), alternating current frequency (100 kHz), light spot width (40 μm), and sample flow rate (0.9 μl/min). Analysis of mixed liquid samples collected at the chip's outlet reveals a reduction in the proportion of H. pluvialis from 37.5% to 1.2% after separation. In summary, this study proposes an ODEP microfluidic system capable of continuously separating and purifying microalgae with different biological characteristics, showcasing its potential as an alternative to traditional labor-intensive microalgae separation techniques.

Preparation, Purification, Characterization and Antioxidant Activity of Rice Bran Fermentation Broth with Hypsizigus marmoreus

The main purpose of this study was to investigate the composition, characterization and antioxidant activity of rice bran fermentation broth, and provide a new way for high-value utilization of rice bran. Firstly, we fermented rice bran with Hypsizigus marmoreus and purified fermentation broth with macroporous resins. We took feruloyl oligosaccharides (FOs) concentration as the measure index, and the results showed that the maximum concentration of FOs was 0.72 mmol/L on the 6th day of rice bran fermentation. We took D101 macroporous resin as adsorption resin for rice bran fermentation broth, and the result showed that FOs concentration reached 2.38 mmol/L with the optimal purification process at pH 4.5, temperature 29 °C, ethanol concentration 55%, sample flow rate 1.5 mL/min, sample concentration 1.7 mL/min and elution flow rate 2.0 mmol/L. Secondly, the characters of rice bran fermentation broth were identified by high-performance liquid chromatography (HPLC) and Fourier-transform infrared spectroscopy (FTIR). These methods showed the presence of ferulic acid (FA), arabinose, xylose and glucose in rice bran fermentation broth. Finally, the in vitro antioxidant activities of rice bran fermentation broth were tested and the result showed that fermentation broth had good antioxidant activities and significantly improved after purification.

Abstract 7495: Validation of microfluidic isolation of circulating pancreatic tumor cells from blood

Abstract Background. Pancreatic ductal adenocarcinoma (PDAC) has a poor prognosis and is the fourth leading cause of cancer-related deaths in the US. PDAC is diagnosed in the late stages, which limits treatment options and yields poor clinical outcomes. Recurrence is a significant issue for patients undergoing surgery for PDAC. Circulating tumor cells (CTCs) are thought to be a potential mediator of recurrence, facilitating the formation of secondary tumor sites after surgery. Thus, there is a need to isolate CTCs to improve understanding of disease recurrence, to ultimately improve outcomes. Herein, we aim to validate our inertial microfluidic (iMF) system for isolating pancreatic CTCs from blood. We also benchmark our iMF system to a commercially available immunomagnetic negative selection system, EasySep™, and quantify target cell recovery and cell enrichment. Methods. Our iMF system employs the differential cell sizes of CTCs from blood cells and inertial migration of such cells in a straight microchannel (150 µm × 50 µm × 24 mm) to enrich CTCs from blood. The iMF system sample flow rate used is 100 µL/min, with a 200 µL/min PBS buffer flow rate. The EasySep™ Direct Human CTC Enrichment kit targets CD2, CD14, CD16, CD19, CD45, CD61, CD66b, and Glycophorin to remove blood cells from the sample using magnetic particles, thereby separating them from CTCs. We spiked low cell concentrations of 50, 100, and 500 Hoechst-stained pancreatic carcinoma cells, PANC1, in 1 mL of healthy blood then captured using either EasySep™ or iMF. Cell enumeration was performed after centrifugation or Cytospin. Results. PANC1 cells and WBCs have average sizes of 18 µm and 8.4 µm, respectively. We characterized our iMF device to capture cells ≥ 12 µm, which yields capture of most PANC1 cells. Indeed, our iMF system achieved 82.8±19.2%, 72.5±16.3%, and 59.3±3.8% recovery for 50, 100, and 500 cell-spikes in lysed blood, respectively. For the same 50, 100, and 500 cell-spikes, the total iMF CTC yields after Cytospin were 46.3±11.8, 44.3±9.1, and 32.7±2.1%, while the total CTC yields from EasySep™ were 4.6±3, 5.3±2.1, 8.3±1%, respectively. When we processed whole blood directly, EasySep™ had lower cell recovery, 3.8±0.2, 4.6±1, and 3.3±0.4%, respectively. Our system also demonstrated 8 × higher target cell enrichment compared to EasySep™. Blood lysis before iMF separation did not drastically affect the recovery of target cells. Conclusions. We determined that our system has improved performance over the commercial isolation system, EasySep™, thereby validating the effectiveness of microfluidic isolation for PDAC. In future studies, we can then use our iMF system in CTC isolation from routine blood draws from PDAC patients undergoing surgical resection. We may then isolate real patient samples and study relevant phenotypes of PDAC CTCs which may therefore be used for identifying certain mechanisms of PDAC progression. Citation Format: Celine Macaraniag, Ifra Khan, Jian Zhou, Pier Cristoforo Giulianotti, Alain Borgeat, Gina Votta-Velis, Ian Papautsky. Validation of microfluidic isolation of circulating pancreatic tumor cells from blood [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 7495.

A hydrodynamic-based dual-function microfluidic chip for high throughput discriminating tumor cells

A hydrodynamic-based microfluidic chip consisted of two function units that could not only separate tumor cells (TCs) from whole blood but also remove residual blood cells was designed. The separation of TCs was achieved by a straight contraction-expansion array (CEA) microchannel on the front end of the chip. The addition of contractive structure brought a micro-vortex like Dean vortex that promoted cell focusing in the channel, while when cells entered the dilated region, the wall-induced lift force generated by the channel wall gave cells a push away from the wall. As the wall-induced lift force is proportional to the third power of the cell diameter, TCs with larger diameter will have a larger lateral migration under the wall-induced lift force, realizing the separation of TCs from blood sample. Fluorescent particles with diameters of 19.3 μm and 4.5 μm were used to simulate TCs and red blood cells, respectively, to verify the separation capacity of the proposed CEA microchannel for particles with different diameter. And a separation efficiency 98.7% for 19.3 μm particles and a removal rate 96.2% for 4.5 μm particles was observed at sample flow rate of 10 μL min−1 and sheath flow rate of 190 μL min−1. In addition, a separation efficiency about 96.1% for MCF-7 cells (stained with DiI) and removal rates of 96.2% for red blood cells (RBCs) and 98.7% for white blood cells (WBCs) were also obtained under the same condition. However, on account of the large number of blood cells in the blood, there will be a large number of blood cells remained in the isolated TCs, so a purification unit based on hydrodynamic filtration (HDF) was added after the separation microchannel. The purification channel is a size-dictated cell filter that can remove residual blood cells but retain TCs, thus achieving the purification of TCs. Combined the CEA microchannel and the purifier, the microchip facilitates sorting of MCF-7 cells from whole blood with a separation rate about 95.3% and a removal rate over 99.99% for blood cells at a sample flow rate of 10 μL min−1, sheath flow rate of 190 μL min−1 and washing flow rate of 63 μL min−1.

Parameter analysis on SO3 measurement in coal-fired flue gas with controlled condensation method

ABSTRACT The accurate, repeatable, and verifiable measurement of SO3/H2SO4 is significant to the reliability operation of coal-fired power plants, as well as environment protection and human health. Although the amount of SO3 in flue gas is very small, and its chemical property is extremely active, the measurement of SO3/H2SO4 is difficult and problematic. The measurement errors of controlled condensation method for SO3/H2SO4 in flue gas were evaluated with a sampling system based on dilute sulfuric acid heating method. In order to improve the test accuracy of this method, the effects of water bath temperature, flue gas sampling flow rate, and spiral condensing tube structure parameters (inner diameter and length of spiral condensing tube) on the recovery efficiency of SO3/H2SO4 were investigated. The results indicate that the recovery efficiency fluctuates in the range between 84.1% and 91.6%, with the water bath temperature increasing from 40°C to 90°C. As the flue gas sampling flow rate increases from .5 L/min to 4 L/min, the recovery efficiency of SO3/H2SO4 shows a gradual tendency of increasing, and the recovery efficiency can be high up to 98.4%. When the inner diameter of the spiral condensing tube increases from 3 mm to 10 mm, the recovery efficiency of SO3/H2SO4 decreases gradually. The recovery efficiency of SO3/H2SO4 increases gradually with the spiral condensing tube length increasing from 900 mm to 2000 mm.

Sampling of atmospheric Hgo using home-made gold-coated sand sorbent prior to analysis by atomic absorption spectrometry

Gold-coated sand for amalgamation was synthesized and applied for the determination of mercury in ambient air using a home-made dual gold trap unit coupled to atomic absorption spectrometer. Gold-coated sand is prepared by chemical reduction of Au(III) solution with hydroxylamine depositing elemental gold on acid-etched sand. A home-made dual gold trap unit which focused time-resolved mercury trapped from the sampling/first trap provided an increase in sensitivity and reliability for the analysis of ultra-trace mercury in air was designed and tested. Instrumental detection and quantitation limits (IDL and IQL) of system were 3.9 and 13pg Hg, respectively. Method detection and quantitation limits (MLOD and MLOQ) of system were 0.04 and 0.13ngHg.m-3 for sampling flow rate of 200mL.min-1 and sampling time of 8 hours. Sampling system for gaseous elemental mercury was set up and cooperated with home-made desorption system were preliminarily applied for analysis of atmospheric mercury in samples collected at Hochiminh city University of Science. The atmospheric mercury concentrations were in range of 2.7 – 8.1ng Hg. m-3 which were comparable to Hg concentration found in other cities in the world.