Waste Fluid Research Articles

Reutilization of thickener from fracturing flowback fluid based on Gemini cationic surfactant

Due to the high cost and environmental damage characteristics of the viscoelastic surfactant (VES) fracturing, a method for recycling the VES from the flowback fluid was proposed in this study. Herein, such VES could be prepared easily and it can be recovered from the flowback fluid based on phase separation by adding a certain amount of hydrochloride acid. Based on this proposed method, the VES in the flowback fluid can be recycled to the greatest extent and the waste fluid can be effectively handled by the base neutralization process. The recycled VES can form wormlike micelles in the aqueous solution, and the fracturing fluid prepared from the recycled VES showed good elasticity and thermal stability. The molecular structure analysis showed that the recycled VES molecules maintained good integrity, which provided a solid basis for recycling the VES from the VES-M fracturing fluid. This technique not only can largely increase the utilization rate of thickener of VES fracturing fluid but also promote the treatment of the flowback fluid in hydraulic fracturing.

Potentially clinically relevant concentrations of Cefazolin, Midazolam, Propofol, and Sufentanil in auto-transfused blood in congenital cardiac surgery

BackgroundUse of donor blood in congenital cardiac surgery increases the risk for post-operative morbidity and mortality. To reduce the need for allogenic blood transfusion a technique for peri-operative mechanical red cell salvage is applied. Blood from the operation site is collected in a reservoir, processed, passed through a lipophilic filter and returned to the patient. Influence of this cellsaver system on coagulation, fibrinolysis and inflammatory markers is known. To our knowledge no studies have been performed on the effects of autotransfusion on drug concentrations. A clinically relevant drug dose could potentially be returned to the patient through the auto-transfused blood, leading to unwanted drug reactions post-operatively. We aimed to measure drug concentrations in blood salvaged from the operation site and in the auto-transfused blood to determine if a clinically relevant drug dose is returned to the patient.MethodsThe study was performed at the Department of Cardiothoracic Surgery of a tertiary university hospital. Blood samples were taken from the reservoir, after processing before the lipophilic filter, the auto-transfused blood, and the waste fluid. Samples were stored at − 80 C and drug concentration for sufentanil, propofol, midazolam and cefazolin were measured using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Drug concentrations measured in the reservoir and the auto-transfused blood were compared and the relative reduction was calculated for each patient.ResultsBlood samples were taken from 18 cellsaver runs in 18 patients, age 0–13 years. Drug concentrations in the reservoir were comparable to concomitant concentrations in the patient. For sufentanil 34% (median, IQR 27–50) of drug concentration was retained from the reservoir in the auto-transfused blood, for midazolam 6% (median, IQR 4–10), for cefazolin 5% (median, IQR 2–6) and for propofol 0% (median, IQR 0–0) respectively.ConclusionDepending on the drug, up to 34% of the drug concentration salvaged from the operation site is returned to the patient through autotransfusion, potentially causing unwanted drug reactions post-operatively. Additionally, influence of a cellsaver system should be considered in pharmacological research during and after congenital cardiac surgery and could result in dose adjustments in the postoperative phase.Trial registrationRegistration at the Dutch Trial Registry (NTR3579) at August 14 2012.

Matrix-effect-free determination of BTEX in variable soil compositions using room temperature ionic liquid co-solvents in static headspace gas chromatography mass spectrometry

Concerns about the environmental impact of shale energy exploration (i.e., hydraulic fracturing and other well stimulation techniques) have risen due to its rapid expansion in the United States and other countries. Soils in shale basins engaged in unconventional oil and gas development can become contaminated by volatile organic compounds (VOCs), such as benzene, toluene, ethylbenzene, and xylenes (BTEX) through mishandling of chemical additives, products, and/or waste fluids. In this study, room temperature ionic liquids (RTILs) were evaluated as solvents in an effort to increase sensitivity and to reduce and normalize matrix effects associated with varying soil compositions during analysis. Headspace gas chromatography mass spectrometry (HS-GC-MS) experiments demonstrated that hydrophilic RTILs 1-ethyl-3-methylimidazolium ethyl sulfate [EMIM][ESO4], 1-ethyl-3-methylimidazolium diethyl phosphate [EMIM][DEP], and tris(2-hydroxyethyl) methylammonium methylsulfate [MTEOA][MeOSO3] normalized the response for BTEX compounds between 2 different soils, sandy loam and sandy clay loam. Furthermore, the optimization of the HS equilibration time to 30 min resulted in the reduction of matrix effects in certified reference soils of sand, clay, and loam textures. Limits of detection and limits of quantification were in the sub- to mid- pg g−1 level in soil. For determination at 1 g of certified BTEX reference soil, the relative standard deviation was within 10% and percent recoveries were above 80% for toluene, ethylbenzene, and xylenes. This method reduces the need to characterize and matrix-match soil texture for calibration purposes. It also reduces the analysis time and increases precision and accuracy for the quantification of BTEX in variable soil matrices relative to standard methods.

Occurrence of sweet refuse at disposal sites: rainwater retention capacity and potential breeding opportunities for Aedes aegypti.

Nectar is the staple diet of adult mosquitoes in the wild, but its availability is inconsistent and can be affected by rainfall. In urban centers, Aedes vectors commonly use man-made containers as their major habitat; however, they can colonize any items replenished by rainfall. Garbage output has increased significantly in recent years, at a time when collection frequency is reducing. Such garbage usually includes organic components, some of which are sweet and can be fed upon by other animals or become can containers for rainwater. Despite evidence that Aedes larvae can thrive in containers comprised of organic waste material, which can be produced by rodents gnawing on fruits or vegetables, and that adults can survive on sweet waste fluids, the capacity of organic waste materials to accumulate rainwater and act as egg deposition sites has not been examined. It is also unknown for how long sweet extracts can sustain the life of adult vectors. Here, we investigated the abundance of sweet leftovers at garbage sites and the rainwater retention capacity of some organic materials through a field survey and laboratory bioassays. We also examined whether sweet waste fluids impact egg hatching success and longevity of Aedes aegypti. The results of this study indicated that sweet products with leftovers are highly prevalent in garbage. When exposed to rain, food items (BAFrc, banana fruit resembling container; and BSPrc, boiled sweet potato resembling container) and the packaging of sweet foods (SMIc, sweetened condensed milk can) retained water. When provided an opportunity to oviposit in cups containing BAF extract (BAFex), BSP extract (BSPex), and SMI extract (SMIex), eggs were deposited in all media. Egg maturation in the BAFex environment resulted in similar larval eclosion success to that resulting from embryo development in a water milieu. Adults maintained on sweet waste extracts had long lifespans, although shorter than that of their sugar solution (SUS)-fed counterparts. Taken together, these results indicated that sweet waste materials are useful to dengue mosquitoes, acting both as oviposition sites and energy sources.

Processing and Utilization of Tempe Liquid Waste to be Organic Fertilizer

The activities of KKN-Tematik program of Industrial Engineering Department conducted in Dukunanyar Village, Dukun Sub-district of Gresik Regency is to provide knowledge and implementation to Small and Medium Industry (IKM) tempe how to manage and utilize tempe liquid waste so as not to pollute the environment. Processing of tempe liquid waste using Adsorbtion method and filtering its function to neutralize liquid waste of tempe. Adsorption is a process of separating water from impurities by absorption of impurities such as fine particles, dissolved cations or odors contained in wastewater. The media used are zeloid stone, activated carbon and charcoal husk. Filtering is the process of irrigation or purification of water to produce clean water, free of odors, organic materials and inorganic materials contained therein. The media used are fibers, sand, and krikil. In addition to processing liquid waste tempe with adsorption method and filtering of liquid waste tempe can be utilized as Liquid Fertilizer Productive (PCP). Productive Liquid Fertilizer (PCP) is a way of utilizing tempe liquid waste with highorganic content to improve soil chemical properties to be better so that the productivity of the plant has increased. For materials used in the manufacture of Liquid Fertilizer is liquid waste tempe and fluid starter EM4. By using appropriate tools for liquid waste processing and utilization of tempe liquid waste into a productive Liquid Fertilizer (PCP) on an ongoing basis can create the integration of appropriate waste treatment, and environmentally friendly

Optimization of Methane Gas Formation Rate with The Addition of EM4 Starter-made from Tofu Liquid Waste and Husk Rice Waste Using Biogas Reactor-Fixed Dome in Langensari West Ungaran

Indonesia is a country that has abundant energy resources, namely oil, gas, coal, geothermal, and so forth. Biogas is an alternative fuel that can be used as a substitute for primary fuel. The term biogas is already familiar to the people, it is because biogas has usefulness as a vehicle fuel, domestic (cooking), and generate electricity. Cow dung has a value of C / N ratio is large enough that 18. Rice husk has a C / N ratio is sufficient High temperatures of 38.9. EM-4 (effective microorganism) is a bacterial culture which is usually used as an activator. In the manufacture of biogas from waste fluids out and chaff has the advantage because the content of the C / N is high enough. The composition of the raw materials used are liquid wastes out of 5 kg and 1 kg of husk-em with the addition of 4500 ml and the resulting calorific value of 1047.9 A fermentation time for 9 days. Ph maintained in neutral or alkaline conditions, namely 7-7.5, because the effectiveness of the methane formation is highly dependent on pH wherein the microorganism will grow and thrive in neutral. The test results has been done is the color of the flame and the time at yield is good enough where the color of the flame produced at day to9 blue with time for 40 seconds.

Environmentally friendly hydraulic fracturing and water-free fracturing technologies

Hydraulic fracturing is an efficient stimulation technology widely employed in the petroleum industry to increase the productivity of oil and gas reservoirs, especially for unconventional reservoirs. A close look at the mechanisms and procedures of hydraulic fracturing is taken in this paper, and the major issues of water utilisation are investigated including sourcing, disposal, and resource conservation. Meanwhile, public concerns and legislative and regulatory issues associated with the environmental impacts of hydraulic fracturing are discussed. In addition, recent technical advances in hydraulic fracturing that aid to mitigate fresh water consumption and related environmental concerns are presented. Moreover, a few existing water-free fracturing technologies that avoid water consumption are reviewed and analysed. By improving the fracturing fluid management performance under the guidance of current regulations, e.g., fluid recycling and waste fluid treatment, hydraulic fracturing technologies for oil and gas reservoir development are becoming more and more environmentally friendly. [Received: February 26, 2015; Accepted: July 17, 2016]

Environmentally friendly hydraulic fracturing and water-free fracturing technologies

Hydraulic fracturing is an efficient stimulation technology widely employed in the petroleum industry to increase the productivity of oil and gas reservoirs, especially for unconventional reservoirs. A close look at the mechanisms and procedures of hydraulic fracturing is taken in this paper, and the major issues of water utilisation are investigated including sourcing, disposal, and resource conservation. Meanwhile, public concerns and legislative and regulatory issues associated with the environmental impacts of hydraulic fracturing are discussed. In addition, recent technical advances in hydraulic fracturing that aid to mitigate fresh water consumption and related environmental concerns are presented. Moreover, a few existing water-free fracturing technologies that avoid water consumption are reviewed and analysed. By improving the fracturing fluid management performance under the guidance of current regulations, e.g., fluid recycling and waste fluid treatment, hydraulic fracturing technologies for oil and gas reservoir development are becoming more and more environmentally friendly. [Received: February 26, 2015; Accepted: July 17, 2016]

Development of Environmentally Conscious Electrodeposition Process "Solid Electrodeposition (SED)"

Conventional electrodeposition process is widely used for various kinds of functional parts such as electronics, anti-corrosion, decoration and so on. However, this process has serious problem due to a large quantity of waste fluid including toxic substance. Recently, environmental regulation has been strengthened, so that the production line may be needed to be closed system for recycling the waste fluids. Moreover, the additionl processes such as masking and etching is indispensable in producing the patterned circuit board, leading to high cost for final products. We have developed the novel electrodeposition process to solve the environmental and cost problems of a conventional electrodeposition. As shown in Fig. 1, the novel deposition system is simply composed of electrodes, metal solution and polyelectrolyte. By applying potential between two electrodes, metal films are deposited at solid-solid interface, i.e., cathode electrode and polyelectrolyte; electrolyte solution is separated from cathode electrode by polyelectrolyte in which metallic ions can be diffused through ion-exchange reaction. Therefore, when this system is accumulated into small probe system, this process enables electrodeposition of metals only by attaching polyelectrolyte surface into cathode surface in a serial patterning manner, whereas conventional electrodeposition process is based on immersing the substrate of interest into electrolyte solution. We call this novel system, “solid electrodeposition (SED)”. The characteristics of the process are as follows. 1) The system needs only small amount of electrolyte solution, and washing of the cathode substrate after metal deposition is not necessary because of growth of the films at solid-solid interface, leading to much small amount of waste solution. 2) Site-selective deposition can be achieved only by controlling the contact area of the polyelectrolyte used for deposition (Fig. 2a). 3) Since the deposition can proceed through diffusion of metal ions through fine, large amount of ion channels in polyelectrolytes, metal films constructing of tiny crystallites are deposited (Fig. 2b). Electrical resistivity of the copper films deposited by SED process is comparable with that of bulk copper, indicating high purity, well-defined copper films are deposited on the substrates. From these results, this process offers an effective, environmentally friendly methodology for fabricating metal films in atmospheric conditions and can be, therefore, applied for various microelectronic applications. Figure 1

DÜŞÜK SICAKLIKLI ATIK AKIŞKAN DESTEKLİ ORGANİK RANKİNE ÇEVRİMLERİNİN OPTİMİZASYONU

In this study, two different cycle systems on the base of Organic Rankine Cycle (ORC) have been designed for heat recovery from the industrial waste fluids at the low temperature to generate electricity using Engineering Equation Solver (EES).The designed cycles are Simple Organic Rankine Cycle (S-ORC) and Regenerative Organic Rankine Cycle (R-ORC). Waste fluid input temperature and mass flow rate are fixed in each cycle. Organic working fluids such as isopentane, isobutane, R134a, R123, R245fa, R22, R13, propane and R600 have been investigated. In order to detect the optimum working fluid, first (T1K) and second law of thermodynamics (T2K) values have been analyzed for each fluid. Finally, our study demonstrated that optimum fluids have been determined for different types of cycles and fluid pressure ranges.

Induced earthquakes in the development of unconventional energy resources

It has long been known that human activities such as waste fluid disposal and reservoir impoundment may cause earthquakes. Recently, anthropogenic activities to tackle the increasing energy demand and to address climate change issues are also reported to induce earthquakes. These activities have a common attribute in that fluids are injected and extracted underground and induce spatiotemporal changes of pore pressure and stress, which may cause slip on faults. Induced earthquakes not only pose significant impacts on seismic hazard assessment and preparation, but also raise the question to the society as how to balance the economic needs of resources development and the public’s concerns about potential environmental impacts. Here we review the observations of fluid-injection/extraction induced earthquakes, ground deformation associated with these activities, and their physical mechanisms. Furthermore, we discuss the influences of induced earthquakes on seismic hazard models, regulatory policies on these anthropogenic activities, and current development of academic, industrial and government initiatives and collaborations in order to understand this intriguing phenomenon and address associated challenges.

Managing potential interactions of subsurface resources

Subsurface resources include oil, gas, coal, groundwater, saline aquifer minerals, and heat (for geothermal use). Pore space itself should also be considered as a resource as it can be used for injection of waste fluids, produced water, storage of natural gas, compressed air, and supercritical CO2. Use of subsurface resources can overlap in space, and pressure changes at one site can remotely influence resource use at other sites. Resource use can also vary in time, such as the use of depleted oil or gas fields for natural gas or CO2 storage. Before allocation of a subsurface resource it is therefore useful to understand the potentially wide range of resources available in an area, how they might be developed successively, and how they could affect each other if used concurrently. While these issues are primarily geological, they have critical significance for legal, environmental, and economic considerations.

Multiple extracellular vesicle types in peritoneal dialysis effluent are prominent and contain known biomarkers.

Peritoneal dialysis inevitability results in activation of inflammatory processes and its efficiency is highly variable between patients. An improved method to isolate biomarkers and study pathophysiological mechanisms in peritoneal dialysis effluent (PDE) is expected to be of much benefit for the development of this treatment approach and help with patient management. Extracellular vesicles (EVs) are released as part of normal cellular processes. Their proteome is expected to reflect both type and health of their cell of origin. Although there is a significant interest in using EVs for “liquid biopsies”, little is reported of their presence or composition in plentiful dialysis waste fluids, including peritoneal dialysis effluent (PDE). Here we determined the presence of EVs in PDE and subsequently characterized their proteome. EVs were first isolated from PDE using differential centrifugation, then a further enrichment using size exclusion chromatography (SEC) was performed. The presence of EVs was demonstrated using transmission electron microscopy, and their particle counts were investigated using nanoparticle tracking analysis and dynamic light scattering. Using tandem mass spectrometry, marker proteins from three types of EVs i.e. apoptotic bodies, ectosomes, and exosomes were identified. The proteomic results demonstrated that the isolation of EVs by differential centrifugation helped enrich for over 2,000 proteins normally masked by abundant proteins in PDE such as albumin and SEC markedly further improved the isolation of low abundant proteins. Gene ontology analysis of all identified proteins showed the marked enrichment of exosome and membrane-associated proteins. Over 3,700 proteins were identified in total, including many proteins with known roles in peritoneal pathophysiology. This study demonstrated the prominence of EVs in PDE and their potential value as a source of biomarkers for peritoneal dialysis patients.

Pathophysiology of Acute Kidney Injury

Acute kidney injury (AKI) is defined as the abrupt loss of kidney excretory function with the accumulation of nitrogenous waste products and fluid overload. The etiologies of AKI are numerous and can largely be classified as prerenal, intrinsic, or postrenal. Complex pathways involving inflammatory mediators, vascular compromise, and direct cellular injury are triggered, and equally as complex pathways, including autophagy and fibrosis, are involved in the recovery. Prerenal azotemia is caused by a reduction in tissue perfusion with resulting AKI. Although acute tubular necrosis is the most common intrinsic etiology, other nephrotoxins and exposures can result in intrinsic injury as well. Postrenal AKI is due to obstruction of urinary flow. Herein, in further detail, the mechanisms, pathophysiology, and manifestations of these causes of AKI are discussed. Research into the mechanisms and development of markers and techniques to advance clinical practice is ongoing.

The effects of drilling fluids and environment protection from pollutants using some models

Among the problems faced by the oil industry the environmental pollution caused by drilling oil wells is, due to the increasing energy demand, heavy reliance on oil share drilling operations are important and vital. The drilling process uses drilling fluids and generates waste fluids and cuttings. Drilling fluids used in drilling operations are including water based drilling fluids (WBF), oil based fluids (OBF) and synthetic based fluids (SBF). The wastes generated in the largest volumes during drilling oil and gas wells are drilling fluids and cuttings. There are several options to manage drilling wastes: discharge, down-hole injection and onshore disposal. In many regions of the world, some types of drilling fluids and drill cuttings may be discharged to the sea if they meet certain environmental requirements. Drilling fluids have operational properties including: maintaining pressure, removing cuttings from the borehole, cooling and lubricating and etc. One of the most particular activities in the industrial world is oil drilling industry like any other industrial activity in the waste and wast returns to the environmental and a plan for processing, refining, and there not delete it Long-term adverse effects of climate on the environment will be lasting. Some of fluids have negative impacts on workforce skin and environment for example base oils/solvents type OBF. In general, SBF have substantially lower environmental impacts than OBF. For preventing of fluids dangerous effects Health, safety and environmental (HSE) experts must be managed their impacts in drilling projects. Also the use of isotherms and kinetics models when using the sorbent to remove pollutants such as heavy metals contained in the fluid and drilling mud to describe the adsorption process was very efficient and the Langmuir and Freundlich models usually have better performance for removing of pollutants into environment protection.

Sweet waste extract uptake by a mosquito vector: Survival, biting, fecundity responses, and potential epidemiological significance

In nature, adult mosquitoes typically utilize nectar as their main energy source, but they can switch to other as yet unidentified sugary fluids. Contemporary lifestyles, with their associated unwillingness to consume leftovers and improper disposal of waste, have resulted in the disposal of huge amounts of waste into the environment. Such refuse often contains unfinished food items, many of which contain sugar and some of which can collect water from rain and generate juices. Despite evidence that mosquitoes can feed on sugar-rich suspensions, semi-liquids, and decaying fruits, which can be abundant in garbage sites, the impacts of sweet waste fluids on dengue vectors are unknown. Here, we investigated the effects of extracts from some familiar sweet home waste items on key components of vectorial capacity of Aedes aegypti. Adult mosquitoes were fed one of five diets in this study: water (WAT); sucrose (SUG); bakery product (remnant of chocolate cake, BAK); dairy product (yogurt, YOG); and fruit (banana (BAN). Differences in survival, response time to host, and egg production were examined between groups. For both males and females, maintenance on BAK extract resulted in marked survival levels that were similar to those seen with SUG. Sweet waste extracts provided better substrates for survival compared to water, but this superiority was mostly seen with BAK. Females maintained on BAK, YOG, and BAN exhibited shorter response times to a host compared to their counterparts maintained on SUG. The levels of egg production were equivalent in waste extract- and SUG-fed females. The findings presented here illustrate the potential of sweet waste-derived fluids to contribute to the vectorial capacity of dengue vectors and suggest the necessity of readdressing the issue of waste disposal, especially that of unfinished sweet foods. Such approaches can be particularly relevant in dengue endemic areas where rainfall is frequent and waste collection infrequent.

Oklahoma experiences largest earthquake during ongoing regional wastewater injection hazard mitigation efforts

AbstractThe 3 September 2016, Mw 5.8 Pawnee earthquake was the largest recorded earthquake in the state of Oklahoma. Seismic and geodetic observations of the Pawnee sequence, including precise hypocenter locations and moment tensor modeling, shows that the Pawnee earthquake occurred on a previously unknown left‐lateral strike‐slip basement fault that intersects the mapped right‐lateral Labette fault zone. The Pawnee earthquake is part of an unprecedented increase in the earthquake rate in Oklahoma that is largely considered the result of the deep injection of waste fluids from oil and gas production. If this is, indeed, the case for the M5.8 Pawnee earthquake, then this would be the largest event to have been induced by fluid injection. Since 2015, Oklahoma has undergone wide‐scale mitigation efforts primarily aimed at reducing injection volumes. Thus far in 2016, the rate of M3 and greater earthquakes has decreased as compared to 2015, while the cumulative moment—or energy released from earthquakes—has increased. This highlights the difficulty in earthquake hazard mitigation efforts given the poorly understood long‐term diffusive effects of wastewater injection and their connection to seismicity.

Some induced seismicity considerations in geo-energy resource development

It is now well established that past and current geo-energy resource recovery operations associated with geothermal systems, oil and natural gas recovery operations, and long-term underground storage of waste fluids can induce earthquakes, some having magnitudes as great as 5–6. Injection into or removal of fluids from existing faults and highly stressed rocks associated with energy resource recovery and waste fluid disposal can generate the stress changes needed for fault rupture and slip along the fault plane. Important aspects of the present state of knowledge of induced seismicity, including causal mechanisms, characteristics of different energy technologies, hydraulic fracturing and waste disposal injection wells, carbon capture and storage, and assessing and managing the hazards and risks from induced seismicity are summarized in this paper. Induced earthquakes occur at shallower depths than natural tectonic earthquakes, and for a given magnitude event, shaking intensity is more severe in the epicentral region of an induced earthquake but dissipates more rapidly with distance than for a natural earthquake. In general, the greater the imbalance between the extraction and injection volumes at a site, the larger the magnitude of an observed induced earthquake. The likelihood of shaking of a given intensity at a given location can change with time for anthropogenic events in response to variations in source locations and fluid injection and withdrawal rates and volumes. Methods to account for these variations in seismic hazard and risk assessment are under development.

Diffusion in Tube Dialyzer.

Nowadays, kidney failure is a problem of many peoples in the world. We know that the main function of kidney is maintaining the chemical quality of blood particularly removing urea through urine. But when they malfunction, the pathologic state known as uremia results in a condition in which the urea is retained in the body. Failure of the kidney results in building up of harmful wastes and excess fluids in the body. Kidney diseases (failures) can be due to infections, high blood pressure (hypertension), diabetes, and/or extensive use of medication. The best form of treatment is the implantation of a healthy kidney from a donor. However, this is often not possible due to the limited availability of human organs. Chronic kidney failure requires the treatment using a tube dialyzer called dialysis. Blood is taken out of the body and passes through a special membrane that removes waste and extra fluids. The clean blood is then returned to the body. The process is controlled by a dialysis machine (tube dialyzer) which is equipped with a blood pump and monitoring systems to ensure safety. So this article investigates the real application of mathematics (diffusion) in medical science, and it also contains the mathematical formulation and interpretation of tube dialyzer in relation to diffusion.

C-reactive protein and interleukin 6 microfluidic immunoassays with on-chip pre-stored reagents and centrifugo-pneumatic liquid control.

We present a fully automated centrifugal microfluidic method for particle based protein immunoassays. Stick-pack technology is employed for pre-storage and release of liquid reagents. Quantitative layout of centrifugo-pneumatic particle handling, including timed valving, switching and pumping is assisted by network simulations. The automation is exclusively controlled by the spinning frequency and does not require any additional means. New centrifugal microfluidic process chains are developed in order to sequentially supply wash buffer based on frequency dependent stick-pack opening and pneumatic pumping to perform two washing steps from one stored wash buffer; pre-store and re-suspend functionalized microparticles on a disk; and switch between the path of the waste fluid and the path of the substrate reaction product with 100% efficiency. The automated immunoassay concept is composed of on demand ligand binding, two washing steps, the substrate reaction, timed separation of the reaction products, and termination of the substrate reaction. We demonstrated separation of particles from three different liquids with particle loss below 4% and residual liquid remaining within particles below 3%. The automated immunoassay concept was demonstrated by means of detecting C-reactive protein (CRP) in the range of 1-81 ng ml-1 and interleukin 6 (IL-6) in the range of 64-13 500 pg ml-1. The limit of detection and quantification were 1.0 ng ml-1 and 2.1 ng ml-1 for CRP and 64 pg ml-1 and 205 pg ml-1 for IL-6, respectively.