Porous Polytetrafluoroethylene Research Articles

Proton conduction of novel calcium phosphate nanocomposite membranes for high temperature PEM fuel cells applications

This work describes the synthesis and evaluation of nanocomposite membranes based on calcium phosphate (CP)/ionic liquids (ILs) for high-temperature proton exchange membrane (PEM) fuel cells. Several composite membranes were synthesized by varying the mass ratios of ILs with respect to the CP and all supported on porous polytetrafluoroethylene (PTFE). The membranes exhibit high proton conductivities. Two ionic liquids were investigated in this study, namely, 1-Hexyl-3- methylimidazolium tricyanomethanide, [HMIM][C4N3−], and 1-Ethyl-3-methylimidazolium methanesulfonate, [EMIM][CH3O3S−]. At room temperature, the CP/PTFE/[HMIM][C4N3−] composite membrane possessed a high proton conductivity of 0.1 S cm−1. When processed at 200 °C, and fully anhydrous conditions, the membrane showed a conductivity of 3.14 × 10−3 S cm−1. Membranes based on CP/PTFE/[EMIM][CH3O3S−] on the other hand, had a maximum proton conductivity of 2.06 × 10−3 S cm−1 at room temperature. The proton conductivities reported in this work appear promising for the application in high-temperature PEMFCs operated above the boiling point of water.

Simultaneous Determination of Ammonia and Humic Acid in Natural Water by Chemiluminescence with Hypobromites

A simultaneous determination method for ammonia and humic acid in water based on the chemiluminescence method was developed. Ammonia was separated by a porous Teflon tube (in a double tube), and separated ammonia was reacted with hypobromite to produce chemiluminescence. By using the synergistic enhancement effect of humic acid for the chemiluminescence, a detection limit for ammonia of 0.41 μmol dm-3 was obtained without any interference from other compounds. Humic acid in the remaining solution coming out from the double tube also reacts with hypobromite to produce chemiluminescence. Ammonia interfered with this chemiluminescence, but the effect was saturated at ammonia concentrations higher than 1 mmol dm-3. The slope for the calibration graph of humic acid was not affected by ammonia concentration, but the value of the intercept for humic acid increased depending on ammonia concentration. Therefore, if the ammonia concentration is known, the humic acid concentration can be determined. The detection limit for humic acid was 1.1 ppb. The present method was applied to the measurement of natural water, and the results obtained by the present method were consistent with those obtained by ion chromatography for ammonia and another reported chemiluminescence method using N-bromosuccinimide for humic acid.

Efficient Portable Urea Biosensor Based on Urease Immobilized Membrane for Monitoring of Physiological Fluids.

Numerous studies have addressed the utilization of glutaraldehyde (GA) as a homobifunctional cross-linker. However, its applicability has been impeded due to several issues, including the tendency of GA molecules to undergo polymerization. Herein, a portable urea biosensor was developed for the real-time monitoring of the flow of physiological fluids; this was achieved by using disuccinimidyl cross-linker-based urease immobilization. Urease was immobilized on a porous polytetrafluoroethylene (PTFE) solid support using different disuccinimidyl cross-linkers, namely disuccinimidyl glutarate (DSG), disuccinimidyl suberate (DSS) and bis-N-succinimidyl-(pentaethylene glycol) ester (BS(PEG)5). A urease activity test revealed that DSS exhibited the highest urease immobilizing efficiency, whereas FT-IR analysis confirmed that urease was immobilized on the PTFE membrane via DSS cross-linking. The membrane was inserted in a polydimethylsiloxane (PDMS) fluidic chamber that generated an electrochemical signal in the presence of a flowing fluid containing urea. Urea samples were allowed to flow into the urea biosensor (1.0 mL/min) and the signal was measured using chronoamperometry. The sensitivity of the DSS urea biosensor was the highest of all the trialed biosensors and was found to be superior to the more commonly used GA cross-linker. To simulate real-time monitoring in a human patient, flowing urea-spiked human serum was measured and the effective urease immobilization of the DSS urea biosensor was confirmed. The repeatability and interference of the urea biosensor were suitable for monitoring urea concentrations typically found in human patients.

Calenderable supramolecular perfluorogels for facile fabrication of slippery coatings

It is challenging to prepare perfluorogels because of the poor solubility and reactivity of perfluorinated polymers. Herein, inspired by the similarity of the fibrous networks of porous polytetrafluoroethylene (pPTFE) to that formed in supramolecular gels, we develop a facile method to prepare supramolecular perfluorogels from pPTFE. The method is based on the soaking of pPTFE in perfluorinated solvents which can swell the amorphous domains of PTFE matrices to ease the sliding of the crystalline domains. The obtained perfluorogels show not only controllable swelling ratio but also extraordinary mechanical properties, including high strength (>4.2 MPa) and modulus (>9.5 MPa), extremely good stretchability (6240%) and malleability (>2300%). Taking advantage of their malleability, the perfluorogel can be easily freehand calendered on objects with various shapes at room temperature to generate slippery coatings with good anti-fouling and antibacterial properties. Moreover, the coatings show interesting compression-induced recovery in surface slipperiness after overlayer liquid is consumed. Because of the daily available starting materials, facile preparation method, and the excellent properties, these perfluorogels might provide immediate application opportunities in various conditions including the current state of COVID-19.

Compound electret-system with improved hydrophobicity and charge stability

In this work, we propose a compound electret-system with improved hydrophobicity and charge stability in water and at elevated temperatures by bonding a solid fluorinated-ethylene-propylene (FEP) film to a porous polytetrafluoroethylene (PTFE) film. Two bonding approaches are investigated, the electrostatic-bonding and melting-bonding, to laminate the FEP and PTFE layers. Experimentally, the compound system shows improved hydrophobicity and charge stability both in water and elevated temperatures compared with the single layer FEP. The contact angles of the compound samples with electrostatic-bonding and melting-bonding are 139 and 124°, respectively. After immersion in water for 16 hours, surface potentials of −406 and −105 V are retained in the samples with electrostatic-bonding and melting-bonding, respectively, which exceeds the single layer FEP. The open circuit thermally stimulated discharge (TSD) current spectra show that the negatively charged electrostatic-bonding sample has a broad positive current peak at 202 °C, while for the melting-bonding sample charged under the same conditions, shows two current peaks at 231 °C and 269 °C. The enhancement of hydrophobicity and charge stability in water for compound systems must be attributed to the specific geometry on the surface of porous PTFE layer, and the improved thermal stability of charges in melting-bonding compound system could be due to the deep charge traps at the interface between FEP and porous PTFE layers generated during heat-pressing process.

Pore-Filled Anion-Exchange Membranes with Double Cross-Linking Structure for Fuel Cells and Redox Flow Batteries

In this work, high-performance pore-filled anion-exchange membranes (PFAEMs) with double cross-linking structures have been successfully developed for application to promising electrochemical energy conversion systems, such as alkaline direct liquid fuel cells (ADLFCs) and vanadium redox flow batteries (VRFBs). Specifically, two kinds of porous polytetrafluoroethylene (PTFE) substrates, with different hydrophilicities, were utilized for the membrane fabrication. The PTFE-based PFAEMs revealed, both excellent electrochemical characteristics, and chemical stability in harsh environments. It was proven that the use of a hydrophilic porous substrate is more desirable for the efficient power generation of ADLFCs, mainly owing to the facilitated transport of hydroxyl ions through the membrane, showing an excellent maximum power density of around 400 mW cm−2 at 60 °C. In the case of VRFB, however, the battery cell employing the hydrophobic PTFE-based PFAEM exhibited the highest energy efficiency (87%, cf. AMX = 82%) among the tested membranes, because the crossover rate of vanadium redox species through the membrane most significantly affects the VRFB efficiency. The results imply that the properties of a porous substrate for preparing the membranes should match the operating environment, for successful applications to electrochemical energy conversion processes.

Novel Composite Membranes Based on Polyaniline/Ionic Liquids for PEM Fuel Cells Applications

The modern development of (PEMFCs) is still faced by several obstacles such as membrane cost and performance. Perfluorosulfonic acid membranes (e.g. Nafion of DuPont) are currently the most successful in PEMFCs. PEMFCs usually operate at temperatures around 80°C and at atmospheric pressure. Higher temperature operation (T >100°C) is preferred and has several advantages including enhanced fuel cell kinetics, improved catalysts tolerance for contaminants and recovery of useful heat. However, the high-temperature operation is not permitted using Nafion membranes as they dehydrate and their proton conductivity dramatically decreases, thus, lowering the fuel cell efficiency. Therefore, this work aims at developing a Nafion-free membrane that would successfully operate at higher temperatures and with reasonable proton conductivity (preferably higher than 10-3 S/cm). In this study, novel solid proton conductors based on polyaniline (PANI) and ionic liquids (ILs) are proposed as membranes in PEMFCs. PANI-IL composite membranes are fabricated using porous polytetrafluoroethylene (PTFE) as support. The composite membrane was evaluated for its proton conductivity. The results showed a high proton conductivity range of 0.01 to 0.02 S/cm when a 3.7 wt % of the ionic liquid (IL)[1-Hexyl-3-Methylimidazolium Tricyanomethanide] was used.

Phosphine Electrochemical Sensor Using Gold-Deposited Polytetrafluoroethylene Membrane.

Phosphine gas is a toxic and flammable gas, which are useful dopant in the semiconducting industry. OSAH (Occupational Safety and Health Administration) regulates the threshold limit value as 0.3 ppm. To detect phosphine gas, an electrochemical sensor cell using gold as a working electrode is available. In this paper, we prepared Au thin film electrode on porous PTFE (polytetrafluoroethylene) membrane by using d.c. sputtering machine. Au thin film deposited on PTFE membrane for 300 s showed the thickness about 220 nm and electrical resistance between 5 and 10 ohm. We adopted this Au thin film as a working electrode and reference electrode. The sensitivity of the electrochemical cell is about 3000 nA/ppm for phosphine gas. Using Cottrell equation and COMSOL program, we simulated the diffusion coefficient of phosphine gas within the electrochemical cell, which showed the value of 1.21×10-7 m²/s.

Ultra-low vanadium ion permeable electrolyte membrane for vanadium redox flow battery by pore filling of PTFE substrate

The proton conductive membranes were prepared by impregnating sulfonated poly(arylene ether ketone) (SP) into the porous polytetrafluoroethylene (PTFE) substrates for vanadium redox flow battery application. To impregnate SP, the surface of porous PTFE was chemically hydrophilized with catechol and polyethyleneimine (PEI). The SP filled PTFE membranes (trPTFE/SP) showed significantly enhanced thermal, dimensional, and mechanical stability, compared with the pristine SP membranes. While the water uptake of trPTFE/SP membranes reduced by only 3–5%, the swelling ratio reduced to about a half and tensile strength increased by 5 times. Although this pore filling process slightly decreased the proton conductivity of the pure SP membranes by 10%, it hugely decreased the vanadium ion permeability about 5 times. Their low vanadium permeability, 1.37 ​× ​10−7 ​cm2 ​min−1–4.21 ​× ​10−7 ​cm2 ​min−1, was even 15 times at most lower than that of Nafion117, 20.28 ​× ​10−7 ​cm2 ​min−1. This low vanadium permeability led to high coulombic efficiency over 96% and energy efficiency around 84% during the 100 charge-discharge cycling tests, which are better than Nafion117 membrane.

Flexible Screen-Printed CNT Electrode on Porous PTFE Substrate with Gold Nanoparticle Modification for Rapid Electrochemical Gas Sensing

Flexible Screen-Printed CNT Electrode on Porous PTFE Substrate with Gold Nanoparticle Modification for Rapid Electrochemical Gas Sensing

Engineering hierarchically structured superhydrophobic PTFE/POSS nanofibrous membranes for membrane distillation

Membrane distillation (MD) is an attractive thermally-driven membrane process for desalination, brine and wastewater treatment. One of the main obstacles impeding MD application is the absence of effective MD membranes with sufficient water permeability and long-term stability. Attributed to the outstanding hydrophobicity, excellent thermal and chemical resistance, the most ideal polymer to develop MD membrane is polytetrafluoroethylene (PTFE). However, the fabrication of PTFE membranes is challenging due to its poor processability. This work describes a novel strategy to develop superhydrophobic and highly porous PTFE membranes via electrospinning. The hydrophobic nanoparticles 8 vinyl-grafted polyhedral oligosilicone (vinyl-POSS) were firstly incorporated into PTFE nanofibers to promote the crystallization of PTFE nanofiber, enhance nanofiber roughness, and improve membrane mechanical robustness and porosity. The effects of vinyl-POSS concentration, temperature and salt concentration of feed solutions on MD performance of PTFE/POSS nanofibrous membranes were investigated systemically in this study. The optimized PTFE/POSS nanofibrous membrane #POSS-2 has a three-dimensional (3D) superhydrophobic property with a water contact angle of 151 ± 4°. It exhibited a competitive water flux of 40 ± 2 Lm−2 h−1 in the direct contact membrane distillation (DCMD) process when the feed and permeate temperatures were 60 and 20 °C, respectively. Moreover, #POSS-2 possessed an excellent long-term stability in a 200-h continuous DCMD operation.

Hyperbranched polyamidoamine modified high temperature proton exchange membranes based on PTFE reinforced blended polymers

A novel type of high temperature proton exchange membrane (PEM) modified by hyperbranched polyamidoamine (HP) and reinforced by polytetrafluoroethylene (PTFE) was prepared by a facile route. Polymers of polyvinylchloride (PVC) and polyvinylpyrrolidone (PVP) were first blended with a mole ratio of 1.2 : 1. The blended polymers were then crosslinked by HP via the SN2 nucleophilic substitution reaction with mass ratios of HP to PVC up to 1 : 1. The alkaline amine-rich HP has high affinities with phosphoric acid (PA) molecules, which could bring on superior proton conductivity while sacrifice mechanical strength of the membranes. Hence the porous PTFE which could reduce the plasticizing effect of PA was introduced to balance the proton conductivity and the mechanical strength of the composite membranes. As a result, PA doped PTFE reinforce composite membrane which doped with 29 wt% HP exhibited a high proton conductivity of 0.154 S cm−1 at 160 °C without humidifying and an excellent tensile stress at break of 22 MPa under ambient atmosphere, which is much better than the PA doped pristine PVP-PVC composite membrane. A single H2/O2 fuel-cell demonstrated that a peak power density of 433 mW cm−2 was achieved at 180 °C by using PA doped PTFE reinforce composite membrane which doped with 29 wt% HP as the electrolyte with no humidification.

Enhancement of Flux Performance in PTFE Membranes for Direct Contact Membrane Distillation.

This work focused on enhancing the flux on hydrophobic polymeric membranes aimed for direct contact membrane distillation desalination (DCMD) process without compromising salt rejection efficiency. Successful coating of commercial porous poly-tetrafluoroethylene membranes with poly(vinyl alcohol) (PVA) was achieved by solution dipping followed by a cross-linking step. The modified membranes were evaluated for their performance in DCMD, in terms of water flux and salt rejection. A series of different PVA concentration dipping solutions were used, and the results indicated that there was an optimum concentration after which the membranes became hydrophilic and unsuitable for use in membrane distillation. Best performing membranes were achieved under the specific experimental conditions, water flux 12.2 L·m-2·h-1 [LMH] with a salt rejection of 99.9%. Compared to the pristine membrane, the flux was enhanced by a factor of 2.7. The results seemed to indicate that introducing hydrophilic characteristics in a certain amount to a hydrophobic membrane could significantly enhance the membrane distillation (MD) performance without compromising salt rejection.

H-shaped partial splenorenal shunting with the use of a reinforced graft made of porous polytetrafluoroethylene.

The study was aimed at improving the immediate and remote results of splenorenal bypass grafting. A total of 57 patients presenting with hepatic cirrhosis, portal hypertension, and recurrent haemorrhage from oesophageal varices underwent an H-shaped partial splenorenal shunt procedure using an externally reinforced 1.5-2.0-cm-long synthetic graft with a diameter equalling half of that of the splenic vein in an end-to-side fashion. Assessment of efficacy of shunting was based on intraoperative measurement of venous pressure in the portal system before and after shunting, the findings of Doppler ultrasonography of the linear velocity of blood flow in the portal, splenic, and left renal veins in the early postoperative period, as well as computed tomography, esophagogastroscopy, and assessment of the degree of hepatic encephalopathy in the remote postoperative period. The findings of intraoperative measurement of venous pressure in the portal vein system before and after shunting demonstrated a statistically significant decrease in (normalization of) portal pressure in all patients after bypass grafting (p≤0.05). There were no severe postoperative complications, in-hospital mortality, nor events of decompensation of hepatic insufficiency. According to the findings of Doppler ultrasonography of the linear velocity of blood flow and control computed tomography after surgery, the splenic vein, left renal vein and the conduit between them remained patent at all terms of postoperative follow up. The findings of control esophagogastroscopy revealed a statistically significant decrease in the degree of oesophageal varices at 3, 6, and 9 months after shunting (p≤0.05). There was no statistically significant difference in the change of the degree of hepatic encephalopathy at 3, 6, and 9 months after shunting (p=0.853, p=0.712, and p=0.581, respectively). At various terms after surgery, nine patients underwent deceased donor liver transplantation, with the splenorenal shunt ligated intraoperatively. This method of splenorenal shunting makes it possible to decrease the risk of bleeding from oesophageal varices and venous thromboses in vascular anastomoses, as well as complications resulting from using autovenous conduits, to decrease the risk of decomposition of hepatic insufficiency and the frequency of the development of encephalopathy in the postoperative period. Besides, this method makes it possible to easily dismantle the previously created artificial portocaval shunt in the process of liver transplantation.

Single-Stage Formation of Film Polymer Composites in Supercritical Colloid Solutions of Nanoparticles Obtained by Laser Ablation

Abstract—A review of earlier studies is presented together with new results on the creation of highly concentrated colloid solutions with nanoparticles of noble metals (gold and silver) in a supercritical carbon dioxide (SC–CO2) medium and the development of a single-stage method for the production of polymer nanocomposites. The effect of the SC–CO2 density on the dynamics of the formation and decomposition of supercritical fluids (SCFs) of silver and gold nanocolloids in the process of pulsed laser ablation and after its termination is studied. The possibility of the formation of colloids from bimetallic nanoparticles was considered. The effective dielectric permittivity of a colloid solution of silver nanoparticles in SC–CO2 is calculated by the numerical modeling of extinction spectra in the dipole approximation at various densities, with consideration for the size of nanoparticles and the degree of their asphericity. The formation of various film nanocomposites based on a porous copolymer polytetrafluoroethylene—vinylidenefluoride with ruby nanoparticles and two modifications of pure porous polytetrafluoroethylene with silver nanoparticles in the same SCF reactor and with a single technological process is considered.

Property Assessment and Application Exploration for Layered Polytetrafluoroethylene Piezoelectrets

Piezoelectrets are piezoelectric polymer foams with oriented macro-dipoles, having promising transducer applications. Here we report the properties of polytetrafluoroethylene (PTFE) piezoelectret films produced by a continuous production line and their application in film transducers. Such samples consist of a porous PTFE core and two compact PTFE outer layers. The results show that the samples are of significant longitudinal piezoelectric d33 coefficients as large as 1300 pC/N in a quasi-static condition. The thermal stability of the PTFE piezoelectret is much superior to that of ordinary polypropylene (PP) piezoelectrets. After annealing treatments at RT, 90 and 120 °C for 25 h, 96, 82, and 49% of the initial d33 values for PTFE samples were retained, respectively, while the d33 value of PP samples dropped to 20% from a small initial value of 168 pC/N after 25 h annealing at 90 °C. The flexible piezoelectric film transducers based on PTFE piezoelectret films exhibited high sensitivity, excellent wetting resistance, and good mechanical stability. The typical sensitivity of the fabricated transducers ranges from 240 to 320 pC/g (g is the gravity of the earth.) for a load mass of 100 g. No significant difference in the sensitivity was observed when the transducer samples were stored in various environments. Such transducers succeed in detecting heart beating and identifying tactile and sliding signals as being employed in wearable devices and artificial skins. In addition, the normalized power of 0.06 μW was output at the resonance frequency and match resistance for an energy harvester based on such transducers.

Parylene-Coated Polytetrafluoroethylene-Membrane-Based Portable Urea Sensor for Real-Time Monitoring of Urea in Peritoneal Dialysate.

A portable urea sensor for use in fast flow conditions was fabricated using porous polytetrafluoroethylene (PTFE) membranes coated with amine-functionalized parylene, parylene-A, by vapor deposition. The urea-hydrolyzing enzyme urease was immobilized on the parylene-A-coated PTFE membranes using glutaraldehyde. The urease-immobilized membranes were assembled in a polydimethylsiloxane (PDMS) fluidic chamber, and a screen-printed carbon three-electrode system was used for electrochemical measurements. The success of urease immobilization was confirmed using scanning electron microscopy, and fourier-transform infrared spectroscopy. The optimum concentration of urease for immobilization on the parylene-A-coated PTFE membranes was determined to be 48 mg/mL, and the optimum number of membranes in the PDMS chamber was found to be eight. Using these optimized conditions, we fabricated the urea biosensor and monitored urea samples under various flow rates ranging from 0.5 to 10 mL/min in the flow condition using chronoamperometry. To test the applicability of the sensor for physiological samples, we used it for monitoring urea concentration in the waste peritoneal dialysate of a patient with chronic renal failure, at a flow rate of 0.5 mL/min. This developed urea biosensor is considered applicable for (portable) applications, such as artificial kidney systems and portable dialysis systems.

Cotton-based naturally wearable power source for self-powered personal electronics

The emergence of wearable electronic products represents the transformation of traditional personal electronic products. Nonetheless, the progress of wearable electronics is greatly limited by the frequent and inconvenient charging of their traditional power units. Therefore, it is desirable to develop a wearable power source that can scavenge biomechanical energy from human motions and then directly power wearable electronics continuously. Here, we demonstrated a naturally wearable cotton triboelectric nanogenerator (C-TENG) based on a piece of cotton in situ on clothes. This wearable C-TENG can power wearable electronics continuously by effectively converting biomechanical energy into electricity. The C-TENG is operated by the friction between the cotton and a porous polytetrafluoroethylene thin film. By naturally integrated on the clothes, the flexible C-TENG can scavenge mechanical energy from the motion of swing arms when people are walking or running. When operated by swinging arms, the output voltage and current of the C-TENG could reach 660 V and 12.5 μA, respectively. This generated electricity can immediately power some wearable electronics like an electronic watch, a running light and a light-emitting diode guiding sign. This naturally wearable C-TENG could pave the way for developing self-powered personal electronics.

Nanofiltration membrane via EGCG-PEI co-deposition followed by cross-linking on microporous PTFE substrates for desalination

It is imperative to fabricate nanofiltration membrane with promising separation performance and stability for desalination and wastewater treatment. In this work, inspired by polyphenol chemistry, composite nanofiltration membrane is facilely manufactured by a combined strategy of epigallocatechin-3-gallate (EGCG)-polyetheylenimine (PEI) co-deposition and trimesoyl chloride (TMC) cross-linking on porous polytetrafluoroethylene (PTFE) substrate. Separation performance of membrane was optimized by controlling EGCG-PEI coating time, EGCG-PEI mass ratio and TMC concentration. Chemical structures and surface properties of the optimal membrane were characterized systematically. It was found that a dense and defect-free selective layer was formed with negatively charged surface and molecular weight cut off of 380 Da (stokes radius of 0.46 nm). Experimental results showed that the optimal membrane yielded a pure water permeability of 9.15 L/(m2·h·bar), high rejections of salts in a sequence of Na2SO4 (95.5%) > MgSO4 (86.3%) > MgCl2 (79.1%) > NaCl (61.4%) and excellent rejections of dyes (99.9% for neutral red, methyl orange and crystal violet) at 0.2 MPa. Moreover, the membrane exhibited favorable structural stability and long-term operation stability due to the strong EGCG-PEI adhesion property and robust interfacial interactions.

Simultaneous and direct determination of urea and creatinine in human urine using a cost-effective flow injection system equipped with in-house contactless conductivity detector and LED colorimeter

This work presents a cost-effective and simple flow injection analysis (FIA) system for simultaneous and direct determination of urea and creatinine in human urine. The FIA system comprises two in-house detectors, a contactless conductivity detector and a light emitting diode (LED) detector. The contactless detector was built as a flow-through detection cell with axial electrodes, commonly known as capacitively coupled contactless conductivity detector (C4D) and the diode detector was fabricated based on the concept of paired emitter detector diodes (PEDD). With appropriate dilution of urine, the sample is directly injected into a stream of glycine-NaOH buffer pH 8.8 (the gas donor stream) and is carried by the carrier through a urease minicolumn for on-line enzymatic hydrolysis. The generated NH3 diffuses from the carrier stream through a porous polytetrafluoroethylene (PTFE) membrane into a stream of deionized water (the acceptor stream) leading to an increase in the signal at the C4D due to the NH3 dissolution in the water. In this system, creatinine is determined based on the Jaffé reaction by merging a stream of alkaline picrate with the gas donor stream. The change in color is detected using the PEDD equipped with two green LEDs. Under the optimum condition, the linear range of urea and creatinine were 30–240 mg L−1 and 10–500 mg L−1, with limits of detection of 9.0 mg L−1 and 0.9 mg L−1, respectively. The proposed system provides satisfactorily good precision (RSD < 3%), with sample throughput of 31 sample h−1 for the two analytes. The FIA system tolerates potential interference commonly found in human urine. The system was successfully applied and validated with selected reference methods.