Adsorbent Cartridge Research Articles

Validación de un método de cromatografía líquida (HPLC-UV/Vis) para la cuantificación de aldehídos en agua de lluvia y aire

Aldehydes are compounds in the atmosphere formed by the photochemical degradation of other organic compounds in the troposphere and can be emitted by natural or anthropogenic sources. [Objective] An analytical method was implemented to quantify aldehyde samples in matrices such as air and rainwater. [Methodology] Aldehyde sampling and analysis were conducted using method TO-11 from the United States Environmental Protection Agency (EPA). Sampling was carried out by using adsorption cartridges coated with a 2,4-DNPH solution, forming a hydrazone with the aldehydes present in the rainwater and the air, which were tested using a liquid chromatograph coupled to a UV-visible detector (HPLC-UV/Vis). To validate the analysis technique and the analytical quality of the results, the following was determined: linearity, sensitivity, quantification limits, detection limits, repeatability, reproducibility, and recovery percentage. In the case of repeatability, the comparison of the Horwitz coefficient of variation was used with the percentages of relative standard deviation (% RSD) of the samples. [Results] The detection and quantification limits obtained range between 0.18 μg/m3 and 3.20 μg/m3 for acetaldehyde and acrolein, respectively, while quantification limits are between 0.62 μg/m3 for acetaldehyde and 4.70 μg/m3 for heptanal, data that characterizes the method’s analytical quality. [Conclusions] In general, the analysis method for aldehydes showed linearity, with R2 values equal to or greater than 0.9991 for each calibration curve, and relative deviation percentage values less than 2.25 %, indicating good precision in the analysis.

Functionalization of cellulose acetate nanofibrous membranes for removal of particulate matters and dyes

Particulates and organic toxins, such as microplastics and dye molecules, are contaminants in industrial wastewater that must be purified due to environmental and sustainability concerns. Carboxylated cellulose acetate (CTA-COOH) nanofibrous membranes were fabricated using electrospinning followed by an innovative one-step surface hydrolysis/oxidation replacing the conventional two-step reactions. This approach offers a new pathway for the modification strategy of cellulose-based membranes. The CTA-COOH membrane was utilized for the removal of particulates and cationic dyes through filtration and adsorption, respectively. The filtration performance of the CTA-COOH nanofibrous membrane was carried out; high separation efficiency and low pressure drop were achieved, in addition to the high filtration selectivity against 0.6-μm and 0.8-μm nanoparticles. A cationic Bismarck Brown Y, was employed to challenge the adsorption capability of the CTA-COOH nanofibrous membrane, where the maximum adsorption capacity of the membrane for BBY was 158.73 mg/g. The self-standing CTA-COOH membrane could be used to conduct adsorption-desorption for 17 cycles with the regeneration rate as high as 97.0 %. The CTA-COOH nanofibrous membrane has excellent mechanical properties and was employed to manufacture a spiral wound adsorption cartridge, which exhibited remarkable separation efficiency in terms of treated water volume, which was 5.96 L, and retention rate, which was 100 %.

Optimization of volatile organic compounds sampling from dairy cow exhaled breath using polymer-based solid-phase extraction cartridges for gas chromatographic analysis

We explored appropriate technical setups for the detection of volatile organic compounds (VOCs) from exhaled cow breath by comparing six different polymer-based solid-phase extraction (SPE) cartridges currently on the market for gas chromatography/mass spectrometry (GC-MS) screening. Exhaled breath was sampled at a single timepoint from five lactating dairy cows using six different SPE cartridges (Bond Elut ENV (ENV); Chromabond HRX (HRX); Chromabond HRP (HRP); Chromabond HLB (HLB); Chromabond HR-XCW (XCW) and Chromabond HR-XAW (XAW)). The trapped VOCs were analyzed by dynamic headspace vacuum in-tube extraction GC-MS (DHS-V-ITEX-GC-MS). Depending on the SPE cartridge, we detected 1174–1312 VOCs per cartridge. Most VOCs were alkenes, alkanes, esters, ketones, alcohols, aldehydes, amines, nitriles, ethers, amides, carboxylic acids, alkynes, azoles, terpenes, pyridines, or sulfur-containing compounds. The six SPE cartridges differed in their specificity for the chemical compounds, with the XAW cartridge showing the best specificity for ketones. The greatest differences between the tested SPE cartridges appeared in the detection of specific VOCs. In total, 176 different VOCs were detected with a match factor >80%. The greatest number of specific VOCs was captured by XAW (149), followed by ENV (118), HLB (117), HRP (115), HRX (114), and XCW (114). We conclude that the tested SPE cartridges are suitable for VOC sampling from exhaled cow breath, but the SPE cartridge choice enormously affects the detected chemical groups and the number of detected VOCs. Therefore, an appropriate SPE adsorbent cartridge should be selected according to our proposed inclusion criteria. For targeted metabolomics approaches, the SPE cartridge choice depends on the VOCs or chemical compound groups of interest based on our provided VOC list. For untargeted approaches without information on the animals’ metabolic condition, we suggest using multi-sorbent SPE cartridges or multiple cartridges per animal.

Effect of Mechanical Vibration on Kinetics of Solute Adsorption

Introduction: Hemadsorption with new sorbent cartridges is an emerging extracorporeal blood purification technique. Flow distribution inside the sorbent is one of the main issues concerning the device’s performance and optimal sorbent utilization. In this experiment, we aimed to investigate the efficacy of vibration during adsorption by measuring the removal of vancomycin. Methods: In this experimental study, 1,000 mL of saline with 10 g of vancomycin was circulated in a closed circuit (set flow of 250 mL/min) simulating a hemadsorption blood run using HA380 minimodule cartridge containing 75 g of wet resin. This vibration model was implemented with a damping head device installed in front of the adsorption cartridge during the experiment. The kinetics of the vancomycin were assessed by removal ratio over 120 min. Results: We found no difference between the two models. Adsorption with and without vibration did not differ significantly for partial reduction ratios, overall amount of adsorbed molecule, or adsorption kinetics. Conclusion: The current design and structure of the minimodule cartridge demonstrated no difference in small-middle solute removal. Further improvement with the addition of mechanical vibration to the device was not observed.

#6814 A NEW SORBENT DEVICE FOR MULTIPLE CLINICAL PURPOSES: CURRENT EVIDENCE AT A PRIVATE HOSPITAL IN MEXICO

Abstract Background and Aims Adsorption is an extracorporeal technique utilized for blood purification, it also complements convection and diffusion for solute removal. Since 1991 we had used blood purification techniques, over the years, new adsorption cartridges had been developed, the new ones involving treatment for inflammatory conditions, chronic uremic symptoms and autoimmune diseases. HA130, HA230, and HA330 (Jafron, Zhuhai City, China) are among the widely used adsorption cartridges in China. We report highlights of the use of hemoperfusion using HA130 cartridges in the Mexican population cohorts in the context of multiple chronic inflammatory conditions in order to support evidence of effectiveness and safety. Method We retrospectively analyzed the medical records of 14 critically ill patients in the context of chronic inflammatory conditions such as acute kidney injury in chronic kidney disease, acute lung injury due to SARS-COV-2 infection and sepsis. Hemoperfusion in addition to standard therapy (fluid resuscitation, vasopressors, antimicrobial therapy and ventilatory support) resulted in the improvement of inflammatory substances levels when compared to standard therapy alone. Out of the 14 patients, 7 patients used HA130 cartridges and 7 patients with standard therapy alone. Results There were no significant side effects associated with HA130 cartridge use. HA 130 cartridges were found to be effective in reducing uremic symptoms in chronic hemodialysis patients, improvement of pruritus score and decreased parathyroid hormone and phosphate product (p<0.5) when compared to HD alone, creatinine (MARS: −24 μmol/L, −19.5 to −10.46, p < 0.001; SPAD: −2 μmol/L, −9.0 to +7.0/L, p = 0.314) and urea (MARS: −0.9 mmol/L, −318 to −0.189, p = 0.024; SPAD: −0.1 mmol/L, −1.0 to +0.68, p = 0.523). 66.6% of cost-effectiveness when compared to standard therapy. Conclusion In the group of patients that used HA130 cartridges we found statistically significant (p <0.05) reduction of pruritus score, PTH, phosphate product, creatine and urea when compared to the group of patients with standard therapy alone. The development in new cartridges technology allows more wide applications for renal patients. As we expand to involve other indications for this therapy there is cost-effectiveness improvement for the patients.More studies in different clinical settings are needed in order to achieve adsorption therapy national recommendations. We also found that the HA130 cartridges are effective in reducing uremic symptoms and microinflammatory status in acute kidney injury in chronic kidney disease patients due to the elimination of middle and small molecule uremic toxins and inflammatory mediators and endotoxins. This may translate as an improvement of quality of life and survive rates in patients with chronic hemodialysis, even though more studies are needed in order to prove this assumption.

Negative alactic base excess is reversed by hemoperfusion in septic patients

Introduction: Gattinoni et al. have recently introduced a new parameter: the “alactic base excess” (ABE). ABE is equivalent to the number of strong acids, other than lactate, which are present in the plasma in abnormal concentrations, negative ABE being associated with higher mortality in sepsis. Hemoperfusion (HPF) is an extracorporeal procedure that involves the passage of blood through an adsorption cartridge, where solutes are removed by direct binding to the sorbent material. Then, it was decided to explore the influence of HPF on negative ABE value in sepsis. Materials and methods: Basal values of ABE, standard base excess (SBE), and lactate (mean, standard deviation [SD]) were obtained. The difference between these parameter values before and after four sessions of HPF (HA330) (delta value) was evaluated. Student’s t-test and Wilcoxon test were applied. Results: From 32 patients (age: 57±13) suffering from respiratory insufficiency secondary to COVID-19 who were treated with HPF in the critical care unit of Clinica de la Mujer, Bogotá (Colombia), 6 patients presented with metabolic acidosis with negative ABE value (‒2.7±1) with negative SBE (‒4.7±1) and high lactate serum value (2±0.7 mmol/L). Delta ABE, SBE, and lactate were: 7.7 (p = 0.005), 6.1 (p = 0.003), and 1.6 (p = NS), respectively. Thus, negative ABE was significantly reversed by HPF, since SBE value turned positive without significant change in lactate. Conclusion: Negative alactic parameter was significantly reversed by HPF in septic patients. It is necessary to carry out evaluations in larger groups to estimate their impact on clinical outcomes.

Ultraporous Polyquaternium-Carboxylated Chitosan Composite Hydrogel Spheres with Anticoagulant, Antibacterial, and Rapid Endotoxin Removal Profiles for Sepsis Treatment.

Hemoperfusion is an important method to remove endotoxins and save the lives of patients with sepsis. However, the current adsorbents for hemoperfusion have disadvantages of insufficient endotoxin adsorption capacity, poor blood compatibility, and so on. Herein, we proposed a novel emulsion templating (ET) method to prepare ultraporous and double-network carboxylated chitosan (CCS)-poly(diallyl dimethylammonium chloride) (PDDA) hydrogel spheres (ET-CCSPD), bearing both negative and positive charges. CCS was introduced to balance the strong positive charges of PDDA to improve hemocompatibility, and emulsion templates endowed the adsorbent with an ultraporous structure for enhanced adsorption efficacy. The ET-CCSPDs neither damaged blood cells nor activated complement responses. In addition, the activated partial thromboplastin time (APTT) was prolonged to 8.5 times, which was beneficial for reducing the injection of anticoagulant in patients. The ET-CCSPDs had excellent scavenging performance against bacteria and endotoxin, with removal ratios of 96.7% for E. coli and 99.8% for S. aureus, respectively, and the static removal ratio of endotoxin in plasma was as high as 99.1% (C0 = 5.50 EU/mL, critical illness level). An adsorption cartridge filled with the ET-CCSPDs could remove 84.7% of endotoxin within 1 h (C0 = 100 EU/mL in PBS). Interestingly, the ET-CCSPDs had a good inhibitory effect on the cytokines produced by endotoxin-mediated septic blood. By developing the ET method to prepare ultraporous and double-network adsorbents, the problems of low adsorption efficiency and poor blood compatibility of traditional endotoxin adsorbents have been solved, thus opening a new route to fabricate absorbents for blood purification.

A Review of Extracorporeal Blood Purification Techniques for the Treatment of Critically Ill Coronavirus Disease 2019 Patients.

In late 2019, a novel betacoronavirus, later termed severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), was discovered in patients with an unknown respiratory illness in Wuhan, China. SARS-CoV-2 and the disease caused by the novel coronavirus, coronavirus disease 2019 (COVID-19), spread rapidly and resulted in the World Health Organization declaring a pandemic in March 2020. In a minority of patients infected with SARS-CoV-2, severe illness develops characterized by a dysregulated immune response, acute respiratory distress syndrome, and multisystem organ failure. Despite the development of antiviral and multiple immunomodulatory therapies, outcomes of severe illness remain poor. In response, the Food and Drug Administration in the United States authorized the emergency use of several extracorporeal blood purification (EBP) devices for critically ill patients with COVID-19. Extracorporeal blood purification devices target various aspects of the host response to infection to reduce immune dysregulation. This review highlights the underlying technology, currently available literature on use in critically ill COVID-19 patients, and future studies involving four EBP platforms: 1) oXiris filter, 2) CytoSorb filter, 3) Seraph 100 Microbind blood affinity filter, and 4) the Spectra Optia Apheresis System with the Depuro D2000 Adsorption Cartridge.

POS-855 MORTALITY RATE AND ACUTE KIDNEY INJURY PREVALENCE REDUCTION IN COVID-19 CRITICAL PATIENTS TREATED WITH HEMOPERFUSION

COVID-19 induced damage is fundamentally reactive since is generated by a series of mediators released during inflammatory overreaction (cytokines storm). Hemoperfusion (HPF) is an extracorporeal technique which involves the passage of blood (or plasma) through an adsorption cartridge, where solutes are removed by direct binding to the sorbent material. HA330 cartridge can bind cytokines. Previous studies have proposed the utility of HPF with HA330 cartridge in reducing cytokines storm negative effects, even in COVID-19.

POS-854 NEGATIVE ALACTIC VALUE IS REVERSED BY HEMOPERFUSION IN SEPTIC PATIENTS

Gattinoni et al. have recently introduced a new internal milieu parameter: the “alactic base excess” (ABE). This variable is obtained by applying the following equation: ABE mmol/L = standard base excess (SBE) mmol/L + lactate mmol/L, being standard base excess mmol/L = [bicarbonate mmol/L - 24.8 mmol/L] + 16.2 mmol/L x (pH - 7.4). In a clinical setting, a negative ABE value is directly related to fix acid retention, and is associated with higher mortality in septic patients. Hemoperfusion (HPF) is an extracorporeal technique which involves the passage of blood (or plasma) through an adsorption cartridge, where solutes are removed by direct binding to the sorbent material.

Reverse takotsubo cardiomyopathy in fulminant COVID-19 associated with cytokine release syndrome and resolution following therapeutic plasma exchange: a case-report

BackgroundFulminant (life-threatening) COVID-19 can be associated with acute respiratory failure (ARF), multi-system organ failure and cytokine release syndrome (CRS). We present a rare case of fulminant COVID-19 associated with reverse-takotsubo-cardiomyopathy (RTCC) that improved with therapeutic plasma exchange (TPE).Case presentationA 40 year old previous healthy male presented in the emergency room with 4 days of dry cough, chest pain, myalgias and fatigue. He progressed to ARF requiring high-flow-nasal-cannula (flow: 60 L/minute, fraction of inspired oxygen: 40%). Real-Time-Polymerase-Chain-Reaction (RT-PCR) assay confirmed COVID-19 and chest X-ray showed interstitial infiltrates. Biochemistry suggested CRS: increased C-reactive protein, lactate dehydrogenase, ferritin and interleukin-6. Renal function was normal but lactate levels were elevated. Electrocardiogram demonstrated non-specific changes and troponin-I levels were slightly elevated. Echocardiography revealed left ventricular (LV) basal and midventricular akinesia with apex sparing (LV ejection fraction: 30%) and depressed cardiac output (2.8 L/min) consistent with a rare variant of stress-related cardiomyopathy: RTCC. His ratio of partial arterial pressure of oxygen to fractional inspired concentration of oxygen was < 120. He was admitted to the intensive care unit (ICU) for mechanical ventilation and vasopressors, plus antivirals (lopinavir/ritonavir), and prophylactic anticoagulation. Infusion of milrinone failed to improve his cardiogenic shock (day-1). Thus, rescue TPE was performed using the Spectra Optia™ Apheresis System equipped with the Depuro D2000 Adsorption Cartridge (Terumo BCT Inc., USA) without protective antibodies. Over 5 days he received daily TPE (each lasting 4 hours). His lactate levels, oxygenation, and LV function normalized and he was weaned off vasopressors. His inflammation markers improved, and he was extubated on day-7. RT-PCR was negative on day-17. He was discharged to home isolation in good condition.ConclusionStress-cardiomyopathy may complicate the course of fulminant COVID-19 with associated CRS. If inotropic therapy fails, TPE without protective antibodies may help rescue the critically ill patient.

P0642EFFECTIVENESS OF HEMADSORPTION IN REDUCING FREE LIGHT CHAINS IN PATIENTS WITH MULTIPLE MYELOMA A.M.FOMIN, A.V.VATAZIN MOSCOW REGIONAL RESEARCH AND CLINICAL INSTITUTE. MOSCOW, RUSSIAN FEDERATION

Abstract Background and Aims Acute kidney injury is a frequent complication of multiple myeloma with unfavorable prognostic significance. The aim of the present study is to evaluate the effectiveness of hemadsorption to reducing free light chains (FLCs) in patients with multiple myeloma without replacement kidney therapy. Method The research was conducted for 6 patients ages 65- 74 with multiple myeloma. All patients were already suffering from a mild degree of renal insufficiency and elevated free light chains (4 kappa, 2 lambda). All patients didn’t have renal replacement therapy. Patients received VMP induction chemotherapy after two sessions of hemadsorption. The level of creatinine was from 198 µmol/l to 289 µmol/l. The glomerular filtration rate (eGFR) was from 34,8 to 21,3 mL/min/1,73 m2. The level of kappa FLC was 1714 – 5600 mg/L. The level of lambda FLC was 1575 – 3220 mg/L. In CytoSorb therapy, the blood is purified by adsorption in a procedure similar to hemoperfusion. The hemadsorption procedures were carried out on the AK10 device (Gambro, Sweden) with use of CytoSorb adsorbent cartridge. The content of the CytoSorb cartridge consists of a highly porous high-tech polymer. The patients were treated with 2 CytoSorb hemoadsorption treatments for 10 hours each separated and from one another by a pause interval of 12-14 hours. The blood flow rate was 130-160 ml/min. Anticoagulation was ensured by washing the bloodlines and a cartridge with a sorbent with normal saline with heparin – 4,000 units of activity per 1 L. 5,000 units of activity of heparin were injected intravenously at the beginning of the procedure. The FLCs, the level of creatinine and coagulogram test results of patients were studied prior to procedure and upon termination of procedure. Results An extracorporeal blood purification methods reduce elevated levels of FLCs. The cartridge with a total surface of&amp;gt;40,000 square meters, an adsorber is able to effectively and over time lower hydrophobic (water-insoluble) molecules that can be removed up to a size of 55kDa. FLC have high molecular weight (monomeric kappa of 22.5 kDa, dimeric lambda of 45 kDa). FLC removal, combined with chemotherapy may be associated with renal function recovery. As a result of hemadsorption after carrying out two procedures, there was a significant decrease in level kappa FLCs by 78.3 %, lambda FLCs by 64,0 %. All patients were dialysis independent. The level of creatinine decreased and the glomerular filtration rate increased. Other blood chemistry parameters did not show any changes. Throughout the treatment, the study did not show a decrease in dynamics of hemoglobin or platelets. There were not negative dynamics in change of INR (international normalized ratio), APTT (activated partial thromboplastin time), level of fibrinogen, prothrombin, or anti-thrombin III. No bleeding complication occurred in any patient during the procedure of hemadsorption. Other biochemical values did not change significantly. Conclusion The research showed that an extracorporeal blood purification method by CytoSorb therapy reduce elevated levels of FLCs in patients with multiple myeloma. The benefits of this modality need confirmation with a randomized controlled trial.

Cytokine adsorption is a promising tool in the therapy of hemophagocytic lymphohistiocytosis

Hemophagocytic lymphohistiocytosis is a life-threatening clinical syndrome caused by severe hypercytokinemia brought on by a highly stimulated but ineffective immune response. Animal studies and case series have demonstrated that a reduction in blood cytokine levels achieved with an extracorporeal adsorption cartridge that contains blood-compatible porous polymer beads (CytoSorb®) can effectively attenuate the inflammatory response during sepsis and possibly improve outcomes. We report a case series of two patients in which three episodes of severe hemophagocytic lymphohistiocytosis triggered by infections with herpesviridae were treated successfully with cytokine adsorption. A marked decrease in interleukin-6 plasma levels and a stable or decreasing need of vasopressor therapy were the most significant results of this treatment. Importantly, treatment was safe and well-tolerated, without any adverse events.

Efficacy of Coupled Plasma Filtration Adsorption in Treating Patients with Severe Intra-Abdominal Infection: A Retrospective Study.

Background: Coupled plasma filtration adsorption (CPFA) is an extracorporeal treatment based on plasma filtration associated with an adsorbent cartridge and hemofiltration. CPFA is able to remove inflammatory mediators and it has been used to treat severe sepsis and multiple organ dysfunction. Limited experience exists on the use of CPFA in treating intra-abdominal infection (IAI). Methods: In this study, the efficacy of CPFA in treating patients with severe IAI and liver failure was evaluated in a retrospective analysis of 76 cases. Results: The survival rate of patients treated with CPFA was 82.6%, with effective removal of endotoxin and inflammatory mediators. Conclusion: Our data suggest that CPFA can be safely and effectively used to lower morbidity and mortality rates of patients with severe IAI and liver failure.

Investigation of BTEX Adsorption on Carbon Nanotubes Cartridges from Air Samples

The volatile organic compounds (VOCs) contribute to serious air pollution problems in Viet Nam. Many studies have investigated in air quality monitoring and treatment, in order to determine the average concentrations of Benzene, Toluene, Ethylbenzene and Xylene (BTEX). Carbon nanotubes (CNTs) have been widely used as adsorbent in environmental treatment, especially for VOCs. This paper aims to determine the adsorption capacity of multiwalled carbon nanotubes for removal of BTEX from air samples. In preliminary study, the effects of various parameters during adsorption experiments were monitored such as flow rate, temperature and BTEX concentrations in air samples. The equipment for BTEX removal was developed by our research team consisting of filter columns, air sample bags, adsorption cartridge. The air samples containing BTEX were conducted directly through a cartridge packed with adsorbent. The adsorption experiments were carried out under various operating conditions such as temperature (30 - 40°C), gas concentration (0,57 - 4,77 mg/L) and the gas flow rate (10 - 90 mL/min). In addition, isotherm studies of CNTs for BTEX removal were achieved by using Langmuir and Freundlich models. The results showed that the experimental parameters were optimized at a flow rate of 30 mL/min and an ambient temperature at 30°C. The adsorption capacity of CNTs increased proportionally with BTEX concentrations. The specific affinity of CNTs for BTEX from air samples was in order of X &gt; E &gt; T &gt; B. The experimental isotherm data were well-fit with the Langmuir model for Benzene and Xylene removal, and the Freundlich model for Toluene and Ethylbenzene adsorption. The CNTs presented highly potential application for BTEX adsorption thanks to their microporous structure and high surface area.

Biocompatibility and Cytotoxic Evaluation of New Sorbent Cartridges for Blood Hemoperfusion

Background/Aims: The use of adsorption cartridges for hemoperfusion (HP) is rapidly evolving. For these devices, the potential induced cytotoxicity is an important issue. The aim of this study was to investigate potential in vitro cytotoxic effects of different sorbent cartridges, HA130, HA230, HA330, HA380 (Jafron, China), on U937 monocytes. Methods: Monocytes were exposed to the sorbent material in static and dynamic manners. In static test, cell medium samples were collected after 24 h of incubation in the cartridges. In dynamic test, HP modality has been carried out and samples at 30, 60, 90, and 120 min were collected. Results: Compared to control samples, there was no evidence of increased necrosis or apoptosis in monocytes exposed to the cartridges both in the static and dynamic tests. Conclusion: Our in vitro testing suggests that HA cartridges carry an optimal level of biocompatibility and their use in HP is not associated with adverse reactions or signs of cytotoxicity.

Preparation and analysis of zero gases for the measurement of trace VOCs in air monitoring

Abstract. Air quality observations are performed globally to monitor the status of the atmosphere and its level of pollution and to assess mitigation strategies. Regulations of air quality monitoring programmes in various countries demand high-precision measurements for harmful substances often at low trace concentrations. These requirements can only be achieved by using high-quality calibration gases including high-purity zero gas. For volatile organic compound (VOC) observations, zero gas is defined as being hydrocarbon-free and can be, for example, purified air, nitrogen or helium. It is essential for the characterisation of the measurement devices and procedures, for instrument operation as well as for calibrations. Two commercial and one self-built gas purifiers were tested for their VOC removal efficiency following a standardised procedure. The tested gas purifiers included one adsorption cartridge with an inorganic media and two types of metal catalysts. A large range of VOCs were investigated, including the most abundant species typically measured at air monitoring stations. Both catalysts were able to remove a large range of VOCs whilst the tested adsorption cartridge was not suitable to remove light compounds up to C4. Memory effects occurred for the adsorption cartridge when exposed to higher concentration. This study emphasises the importance of explicitly examining a gas purifier for its intended application before applying it in the field.

Removal of stabilizers from human serum albumin by adsorbents and dialysis used in blood purification.

IntroductionHuman serum albumin (HSA) is a monomeric multi-domain protein that possesses an extraordinary binding capacity. It plays an important role in storing and transporting endogenous substances, metabolites, and drugs throughout the human circulatory system. Clinically, HSA is used to treat a variety of diseases such as hypovolemia, shock, burns, hemorrhage, and trauma in critically ill patients. Pharmaceutical-grade HSA contains the stabilizers sodium caprylate and N-acetyltryptophanate to protect the protein from oxidative stress and to stabilize it for heat treatment which is applied for virus inactivation.Material and methodsThe aim of this study was to determine if the two stabilizers can be depleted by adsorbent techniques. Several, adsorbents, some of them are in clinical use, were tested in batch and in a dynamic setup for their ability to remove the stabilizers. Furthermore, the removal of the stabilizers was tested using a pediatric high flux dialyzer.ResultsThe outcome of this study shows that activated charcoal based adsorbents are more effective in removal of N-acetylthryptophanate, whereas polystyrene based adsorbents are better for the removal of caprylate from HSA solutions. An adsorbent cartridge which contains a mix of activated charcoal and polystyrene based material could be used to remove both stabilizers effectively. After 4 hours treatment with a high flux dialyzer, N-acetyltryptophanate was totally removed whereas 20% of caprylate remained in the HSA solution.

A regenerable potassium and phosphate sorbent system to enhance dialysis efficacy and device portability: a study in awake goats.

Patients on standard intermittent haemodialysis suffer from strong fluctuations in plasma potassium and phosphate. Prolonged dialysis with a wearable device, based on continuous regeneration of a small volume of dialysate using ion exchangers, could moderate these fluctuations and offer increased clearance of these electrolytes. We report in vivo results on the efficacy of potassium and phosphate adsorption from a wearable dialysis device. We explore whether equilibration of ion exchangers at physiological Ca 2+ , Mg 2+ and hypotonic NaCl can prevent calcium/magnesium adsorption and net sodium release, respectively. Effects on pH and HCO3- were studied. Healthy goats were instrumented with a central venous catheter and dialysed. Potassium and phosphate were infused to achieve plasma concentrations commonly observed in dialysis patients. An adsorption cartridge containing 80 g sodium poly(styrene-divinylbenzene) sulphonate and 40 g iron oxide hydroxide beads for potassium and phosphate removal, respectively, was incorporated in a dialysate circuit. Sorbents were equilibrated and regenerated with a solution containing NaCl, CaCl 2 and MgCl 2 . Blood was pumped over a dialyser and dialysate was recirculated over the adsorption cartridge in a countercurrent direction. Potassium and phosphate adsorption was 7.7 ± 2.7 and 4.9 ± 1.3 mmol in 3 h, respectively. Adsorption capacity remained constant during consecutive dialysis sessions and increased with increasing K + and PO43-. Equilibration at physiological Ca 2+ and Mg 2+ prevented net adsorption, eliminating the need for post-cartridge calcium and magnesium infusion. Equilibration at hypotonic NaCl prevented net sodium release Fe 2+ and arterial pH did not change. Bicarbonate was adsorbed, which could be prevented by equilibrating at HCO3- 15 mM. We demonstrate clinically relevant, concentration-dependent, pH-neutral potassium and phosphate removal in vivo with small volumes of regenerable ion exchangers in our prototype wearable dialysis device. Application of the selected ion exchangers for potassium and phosphate removal in a wearable dialysis device appears to be effective with a low-risk profile.

Validation and modelling of a novel diffusive sampler for determining concentrations of volatile organic compounds in air

A novel diffusive sampler that combines radial and axial diffusion has been developed that improves upon existing commercially available designs. The POcket Diffusive (POD) sampler has been validated under laboratory and field conditions for the measurements of VOCs in ambient air. Laboratory tests varied sampling conditions of temperature (−30–40 C), humidity (10–80%), wind velocity (0.1–4 m s−1), and concentration (0.5–50 μg m−3) for a number of specific VOCs. An overall uncertainty of circa 9% for the measurement of benzene is calculated for the validation tests, in compliance with the data quality objectives of the EU air quality directive 2008/50/EC. A semi-empirical diffusion model has been developed to estimate sampling rates for compounds that were not tested, and for conditions outside of tested ranges during validation. The diffusion model (and validation tests) shows a low influence of environmental conditions on the sampling rate for the POD sampler. Average reproducibility values of circa 3% are reported with overall sampling uncertainties ranging from 9% to 15%, for the whole range of tested conditions, depending on the compound. The adsorbent cartridge is compatible with existing thermal desorption systems in the market. The diffusive sampler can modify the sampling rate by changing the diffusive body within a range of different porosities. Field tests, conducted in parallel with independent quality controlled canister sampling, confirmed the ease of use and quality of VOC measurements with the POD sampler, for compounds that were, and were not, evaluated during laboratory tests.