Detection Of Magnetic Particles Research Articles

Rapid Measurement of Magnetic Particle Concentrations in Wildland–Urban Interface Fire Ashes and Runoff Using Compact NMR

Wildfires are increasing in size, frequency, and intensity, releasing increased amounts of contaminants, including magnetic particles, into the surrounding environment. The aim of this paper is to develop a sensing method for the detection and quantification of magnetic particles (MPs) in fire ash and fire runoff using a compact Time-Domain Nuclear Magnetic Resonance (TD-NMR) system. The system is made up of custom NMR electronics with a compact and rugged permanent magnet array designed to enable future deployment as an in situ sensor. A signal-to-noise ratio of 25 dB was measured for a single scan, and sufficient data can be acquired in one minute. A linear relationship with an R <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> value of 0.9699 was established between transverse relaxation rates and MP concentrations in ash samples. This was validated by testing known dilutions of pure magnetite particles and showing that they fit within the same linear curve. The developed approach was then applied to detect MPs in surface water, where changes in the relaxation rates as high as 400% were observed before and after a wildfire event. MPs were removed from the surface water using a magnetic particle separator to confirm that observed changes were solely due to the presence of MPs. The compact NMR system can be used as a simple and rapid approach to track and quantify the concentrations of magnetic particles released from fire ashes and also from other sources such as discharges from coal ash and other combustion ashes.

Magnetic particle detection as a surface soil source pollution in urban areas: Implication from magnetic and geochemical analysis along the major port city in China

The global concern for the level and sources of urban surface soil pollution has been increasing. In this study, we assessed the efficacy of the environmental magnetic method in identifying the sources of urban surface soil pollution in Ningbo, a prominent city in China. To achieve this, magnetic and geochemical measurements were performed on surface soil samples collected from 114 designated sites， supplemented by polarizing microscope observations. The mass-specific magnetic susceptibility values (χlf) exhibited a wide range, spanning from 25.45 to 1903.85 × 10−8m3kg−1, with an average of 295.45 × 10−8m3kg−1. Notably, lower magnetite concentrations were identified in the urban center, contrasting with higher values observed in the peripheral industrial areas. The average concentrations of Cu, Pb, Zn, and Ca were much higher than the background values. Anthropogenic sources such as traffic emissions, construction dust, and industrial processes emerged as the predominant contributors to surface soil pollution in Ningbo. Fuzzy cluster analysis was employed to discern possible relationships between magnetic properties and pollution sources. The results indicated three categories of pollution. Cluster 1 is related to natural (lithogenic and pedogenic) magnetic mineral sources, and the samples contained abundant quartz or feldspar. Notably, these samples are largely unpolluted. Cluster 2 is associated with a combination of natural and anthropogenic sources. Cluster 3 is dominated by spherical magnetic particles formed by high-temperature combustion. In Cluster 3 topsoil samples, ascertained to be contaminated through magnetic analysis, a significant Spearman correlation was observed between magnetic parameters and Cu, Cr, and Fe. In conclusion, magnetic properties provide a swift and effective method for characterizing surface soil pollution in Ningbo, enabling the tracing of sources for trace metals in the surface soil.

Superferromagnetic Sensors

The strong ferromagnetic nanoparticles are analyzed within the band structure-based shell model, accounting for discrete quantum levels of conducting electrons. As is demonstrated, such an approach allows for the description of the observed superparamagnetic features of these nanocrystals. Assemblies of such superparamagnets incorporated into nonmagnetic insulators, semiconductors, or metallic substrates are shown to display ferromagnetic coupling, resulting in a superferromagnetic ordering at sufficiently dense packing. Properties of such metamaterials are investigated by making use of the randomly jumping interacting moments model, accounting for quantum fluctuations induced by the discrete electronic levels and disorder. Employing the mean-field treatment for such superparamagnetic assemblies, we obtain the magnetic state equation, indicating conditions for an unstable behavior. Respectively, magnetic spinodal regions and critical points occur on the magnetic phase diagram of such ensembles. The respective magnetodynamics exhibit jerky behavior expressed as erratic stochastic jumps in magnetic induction curves. At critical points, magnetodynamics displays the features of self-organized criticality. Analyses of magnetic noise correlations are proposed as model-independent analytical tools employed in order to specify, quantify, and analyze the magnetic structure and origin of superferromagnetism. We discuss some results for a sensor-mode application of superferromagnetic reactivity associated with spatially local external fields, e.g., the detection of magnetic particles. The transport of electric charge carriers between superparamagnetic particles is considered tunneling and Landau-level state dynamics. The tunneling magnetoresistance is predicted to grow noticeably with decreasing nanomagnet size. The giant magnetoresistance is determined by the ratio of the respective times of flight and relaxation and can be significant at room temperature. Favorable designs for superferromagnetic systems with sensor implications are revealed.

A Method for Preparing Superparamagnetic Nanomaterial

Substances with superparamagnetism, a special magnetic effect, are magnetized under external magnetic field. When the applied magnetic field disappears, superparamagnetic substances have almost zero magnetization intensity, with quite small coercivity. The performance of magnetic powder or magnetic suspension used in magnetic particle detection greatly affects detection sensitivity. This paper studies a new method for preparing nano-superparamagnetic non-destructive testing materials by combing membrane technology and chemical co-precipitation method. Magnetic nano-ferroferric oxide particles were prepared by preparing membrane reactor based on chemical co-precipitation method to find the optimal synthesis conditions for nano-ferroferric oxide particles. Polymer nano-magnetic materials with good dispersibility, superparamagnetism, high dispersibility, uniform particle size distribution were obtained, which can well detect cracks, especially small cracks. It is a good magnetic nondestructive testing material.

Visual inspection method of steel pipe surface cracks based on dry magnetic particle feature enhancement

ABSTRACT It’s challenging to use the machine vision to inspect the hot-rolled steel pipes with complex surface texture, uneven colour greyscale, and micro-cracks. On the basis of the principle of magnetic particle detection, a visual inspection method of steel pipe surface cracks based on the dry magnetic particle feature enhancement is proposed, in which the dry red magnetic particles are applied to the steel pipe’s surface to form magnetic particle indication, and complementary colour images are captured in red and green light sources, and image difference is used to eliminate background noise and enhance magnetic particle indication features in view of the fact that the red light source improves and the green light source reduces the magnetic particle indication greyscale. Afterwards, the principle of selection of complementary colours and the detection principle are presented and analysed. Then, the magnetic particle images acquisition and the processing operations of the magnetic particle indication feature enhancement and crack segmentation are presented in detail. Finally, the feasibility of the method proposed in this paper is verified by experiments, and image segmentation metrics demonstrate that it has a good detection effect on the hot-rolled steel pipes with complex surface texture, uneven colour greyscale, and fuzzy cracks.

A Hybrid Paper and 3D Printed Microfluidic Platform for Electrochemical Detection of Ag-Labeled Magnetic Particles

Here we present a hybrid microfluidic device (hyFlow) composed of a disposable paper electrode and a three-dimensional (3D) printed plastic chip for the electrochemical detection of a magnetic bead-silver nanoparticle (MB-AgNP) bioconjugate. Detection of micron-size magnetic conjugates in a paper-only fluidic device is a challenging task. Typically, these devices operate by capillary flow or use paper hollow channels and suffer from flow issues due to entrapment of MB conjugates in cellulose/ nitrocellulose fibers. The hyFlow system was designed to minimize such issues and transport the MB conjugate to the electrochemical detection area without using a syringe pump. Moreover, this device is capable of detecting the MB-AgNP conjugate in both preformed (off-chip) and in-situ formed (on-chip) formats. This portable device can store dried assay reagents in a buffered matrix containing 10% sucrose and 10% D(+)-trehalose and successfully resolvate and mix the reagents in less than 2 min to detect electrochemically. The hyFlow system could detect AgNP labels of preformed MB-AgNP conjugates down to concentrations as low as 12 pM, representing an estimated AgNP coverage of 22 AgNPs per MB.

Development of a new type of automatic magnetic particle inspection wall-climbing robot

In the paper, a permanent magnet adsorption wall-climbing robot using magnetic particle detection technology for crack detection is introduced, which solves the problems of low efficiency of traditional manual detection and long detection time. According to the working environment of the detection system and the detection functions that need to be completed, the body structure of the robot is designed, the overall size of the robot is smaller than the distance between two steam turbine blades, so it can achieve the crack detection function of large steam turbine blades, and the stability and force analysis of the robot are carried out, and the adsorption conditions that meet the conditions of no sliding and overturning are obtained. In the paper, we use the magnetic circuit method to design a miniature excitation device for robotic applications and use the simulation software Ansoft-Maxwell to verify its feasibility. In the final experiment, it can be shown that the robot designed can achieve a series of functions such as magnetic particle inspection and image acquisition. There is a good prospect for the inspection of turbine blades.

Magnetoimpedance Thin Film Sensor for Detecting of Stray Fields of Magnetic Particles in Blood Vessel.

Multilayered [FeNi (100 nm)/Cu (3 nm)]5/Cu (500 nm)/[Cu (3 nm)/[FeNi (100 nm)]5 structures were used as sensitive elements of the magnetoimpedance (MI) sensor prototype for model experiments of the detection of magnetic particles in blood vessel. Non-ferromagnetic cylindrical polymer rod with a small magnetic inclusion was used as a sample mimicking thrombus in a blood vessel. The polymer rod was made of epoxy resin with an inclusion of an epoxy composite containing 30% weight fraction of commercial magnetite microparticles. The position of the magnetic inclusion mimicking thrombus in the blood vessel was detected by the measurements of the stray magnetic fields of microparticles using MI element. Changes of the MI ratio in the presence of composite can be characterized by the shift and the decrease of the maximum value of the MI. We were able to detect the position of the magnetic composite sample mimicking thrombus in blood vessels. Comsol modeling was successfully used for the analysis of the obtained experimental results and the understanding of the origin the MI sensitivity in proposed configuration. We describe possible applications of studied configuration of MI detection for biomedical applications in the field of thrombus state evaluation and therapy.

Detection method of nonlinear magnetized harmonic signal of medical magnetic nanoparticles

Medical magnetic nanoparticles are nano-medical materials with superparamagnetism, which can be collected in the tumor tissue through blood circulation, and magnetic particle imaging technology can be used to visualize the concentration of magnetic nanoparticles in the living body to achieve the purpose of tumor imaging. Based on the nonlinear magnetization characteristics of magnetic particles and the frequency characteristics of their magnetization, a differential detection method for the third harmonic of magnetic particle detection signals is proposed. It was modeled and analyzed, to study the nonlinear magnetization response characteristics of magnetic particles under alternating field, and the spectral characteristics of magnetic particle signals. At the same time, the relationship between each harmonic and the amount of medical magnetic nanoparticle samples was studied. On this basis, a signal detection experimental system was built to analyze the spectral characteristics and power spectral density of the detected signal, and to study the relationship between the signal and the excitation frequency. The signal detection experiment was carried out by the above method. The experimental results showed that under the alternating excitation field, the medical magnetic nanoparticles would generate a spike signal higher than the background sensing signal, and the magnetic particle signal existed in the odd harmonics of the detected signal spectrum. And the spectral energy was concentrated at the third harmonic, that is, the third harmonic magnetic particle signal detection that meets the medical detection requirement could be realized. In addition, the relationship between each harmonic and the particle sample volume had a positive growth relationship, and the detected medical magnetic nanoparticle sample volume could be determined according to the relationship. At the same time, the selection of the excitation frequency was limited by the sensitivity of the system, and the detection peak of the third harmonic of the detection signal was reached at the excitation frequency of 1 kHz. It provides theoretical and technical support for the detection of medical magnetic nanoparticle imaging signals in magnetic particle imaging research.

Development and optimisation of low-power magnetic flux leakage inspection parameters for mild steel welds

Magnetic particle and other magnetic flux leakage (MFL)-based methods for the detection and evaluation of surfacebreaking flaws in ferromagnetic materials typically use high-strength (≥0.5 T RMS), low-frequency (≤50 Hz) magnetic fields. The rationale behind this is the ready availability of strong permanent magnets and mains power for high-strength electromagnets. This high field strength is needed to saturate the sample and compensate for the relatively low sensitivity of magnetic particle detection media, silicon Hall sensors, coils and other magnetic transducers used in such methods. Consequently, frequencies greater than 50 Hz and applied magnetic fields less than 100 mT strength have not been widely explored for MFL due to the lack of commercially available sensors capable of detecting the leakage fields (typically in the nT and μT range) with adequate versatility to cope with the variations in inspection parameters, such as changes in liftoff, material properties, etc, which are inherent to non-destructive testing and evaluation (NDT&amp;E) settings. In this study, the MFL response of surface-breaking longitudinal cracks from a ground mild steel weld validation sample, within the DC to 1 kHz and 5 mT to 100 mT RMS applied magnetic field operating range, was explored. This was carried out to determine whether any optimal frequency response exists, better accommodating the inherent sample material properties (for example magnetic permeability and electrical conductivity) and MFL mechanism and attributing phenomena such as electromagnetic skin effect and eddy current contributions. Contrary to previous work published in Insight last year, this study found no particular optimal frequency within this operating range, with explanations to justify the disproval of previously reported conclusions about optimal frequencies within this range. Also, the iteratively developed quantitative analysis performed in this study can be used to help further understand the underlying mechanisms of AC MFL and provide best practice regarding the optimisation of MFL.

Magnetic particles in the sediments of the south Ukraine rivers as the marker of the technogenic impact on the hydroecosystems

Long-term and large-scale man-made activity in the mining areas affects to all components of the biosphere. The result of mining impact on hydroecosystems is addition to natural sources of sedimentary material technogenic components in large volumes. Magnetic particles are one of technogenic components which come with surface run-off to the river bed. We have studied the content of magnetic particles in the sediments of the south Ukraine rivers: the Inhulets River and the Inhul River ‒ the tributaries of the Dnieper and the Southern Buh, respectively. The Inhulets River flows along the Kryvyi Rih iron ore deposit, parallel the river there is a chain of open-pits, mines, mining and processing plants, a metallurgical plant. The results of our research were demonstrated within the Kryvyi Rih industrial agglomeration a number of magnetic particles in the sediment samples varies from 59,5% to 2,1%. Upstream from the Kryvyi Rih city on 10-15 km a number of magnetic particles is within 1,5%. Based on numerous sources of literature and own researches, it has been determined that detection of magnetic particles and properties is a convenient, cheap, quick and informative method of technogenic pollution studying of river sediments and also mirror the industrial history of the region.

Mooring Chain Working State Detection Device

In order to change the current situation that the mooring chain magnetic particle detection is completely completed manually by workers, and improve the detection coverage accuracy, an automatic mooring chain full-ring magnetic particle detection device has been developed to fill the domestic gap. The device is mainly composed of 4 parts: a vertical scanning mechanism, a circular rotation mechanism, a probe linear motion mechanism and a probe adaptive mechanism, which have a total of 6 degrees of freedom. At the same time, ABAQUS finite element analysis software was used to check the static strength, stiffness and dynamic characteristics of the large-span vertical scanning mechanism in the device. The calculation results show that the static strength and stiffness of the vertical scanning mechanism are reliable; the driving pulsation frequency is far from the main excitation frequency, and the structure has good dynamic characteristics.

Possible Registration of Magnetic Particles in Biological Objects

The possibility of non-invasive detection of magnetic particles in biological objects using magnetic field sensors of various types is investigated. Estimates of the threshold sensitivity of the sensors and the maximum distance at which the sensor can detect magnetic particles are made. It is shown that magnetite particles with a concentration of ∼ 10-9 vol.%, superparamagnetic particles and catalytic particles of the composition “iron in carbon nanotubes” can be fixed by SQUID or combined magnetic field sensors with operating temperatures ∼ 4 K at a distance of ≤ 0.1 m. It is noted that magnetic field sensors with ultra-low threshold sensitivity values (≤ 10-10 T) may be promising for non-invasive control of organs, implants, prostheses and other elements of biological systems.

Magnetomodulating Magnetometer Based on High-Temperature Superconductors

A magnetomodulation magnetic field sensor (MM-MFS) based on a high-temperature superconducting (HTSC) ceramic material in the Bi-2223 system was investigated. A cylindrical HTSC ceramic rod with a length of 10 mm and a diameter of 2 mm was used as a magnetically sensitive element. The MM-MFS operates in a differential mode, which automatically eliminates the effect of odd harmonics in the signal coil. The second harmonic response signal and magnetosensitivity of the sensor depend linearly on the frequency of the excitation field. The parameters of the sensor were experimentally determined, including a magnetosensitivity of about 500 V/T, a threshold sensitivity of about 20 pT, a magnetic field measurement range of approximately ±0.7 mT, and a dynamic measurement range of about 120 dB in the area ±15 µT. According to the estimates, the optimal choice of number of turns, selectivity, and identity of two parts of the excitation coil can significantly reduce the MM-MFS threshold sensitivity to below 1 pT. The MFS-MM can compete with HTSC SQUIDs in biomedical applications for noninvasive detection of magnetic particles and in various implantable devices and artificial organs.

Magnetoimpedance in Samples With Patterned Surfaces for the Detection of Magnetic Particles and Ferrofluids

Magnetoimpedance (MI) has been proposed as a sensible detection method for quantifying the concentration of magnetic microparticle and nanoparticle. The use of samples with severe surface roughness, induced by acid treatments, seems to enhance the detection power. Here, we clarify the role of surface modification in the detection of magnetic particles and ferrofluids. Experimentally, lithography is used to produce a regular pattern of pits in an amorphous ribbon. The influence of the patterning on the MI of the sample, in the presence of magnetic nanoparticles, is analyzed. Contrary to what has been published previously, the patterning seems to worsen the particle detection capability. To clarify the situation, a thorough study is performed with numerical simulations using a finite-element analysis resembling the experimental conditions in a 2-D geometry. The presence of magnetic particles is simulated as a continuum medium with a given permeability, which is a realistic assumption for the case for ferrofluids. The conclusion is that the effect of the magnetic particles on MI depends strongly on the characteristics of the patterning and on the concentration of particles. The simulation results not only qualitatively explain ours experimental results, but also help interpreting previous reports and hints the optimal conditions for the surface patterning in order to maximize the sensibility of the sample to the presence of magnetic particles.

Spin-Valve based magnetoresistive nanoparticle detector for applications in biosensing

A magnetoresistive sensor platform for the detection of individual magnetic reporter particles is presented. The sensing scheme is based on the detection of the shift in the sensor’s magnetoresistance-switching field in the presence of magnetic particle(s). A bottom-pinned spin-valve multilayer (Co/Ru/Co)/Cu/(Co/Ru/Co) device structure (with Ta/Ru seed and Ta capping layers) used for the sensor was deposited using ultra-high vacuum magnetron sputtering and patterned using conventional microfabrication techniques. Inexpensive electronics to measure device magnetoresistance (using DC currents) was used for testing. The detection of individual 500nm Fe3O4 nanoparticles as well as the detection of up to ten (10) nanoparticles was demonstrated and verified using scanning electron microscopy (SEM). The developed sensors are readily integratable into a biosensing platform for the detection of biomolecules at ultra-low concentration using magnetic nanoparticles as reporters.

Experimental Comparison of the Low-Frequency Noise of Small-Size Magnetic Sensors

Small-size ac magnetic-field sensors are used for nondestructive testing (NDT), magnetic particle detection, and other applications, which require high spatial resolution. Up to now, inductive coils dominated this area, as their sensitivity at kHz frequencies, is superior to other magnetic sensors. However, some applications, such as magnetic imaging through conducting sheath, require lower working frequencies, in extreme case units of Hz. We successfully replaced inductive coils by an AMR sensor in NDT application and for distance measurement. In this paper, we compare designs of miniature ac magnetic field sensors, their achievable frequency characteristics, dynamic range, and noise parameters.

Magnetic particles detection by using spin valve sensors and magnetic traps

In this paper, a spin-valve sensor with integrated current lines for concentration and detection of magnetic particles is presented. This device has the advantage of not requiring an external magnetic field source such as permanent magnet to magnetize the particles or to bias the spin-valve sensor. Due to the device design, the magnetic field created by the current lines allows the control of the sensor operating point, to magnetize the particles and also to concentrate the particles in the sensor active area in order to be detected by the spin valve sensor. Detection experiments using FeCrNbB magnetic particles show that the device is capable to detect and quantify the particles in a linear scale over a concentration range of 0.1 to 1 mg/ml.

Resonance-Based Detection of Magnetic Nanoparticles and Microbeads Using Nanopatterned Ferromagnets

Biosensing with ferromagnet-based magnetoresistive devices has been dominated by electrical detection of particle-induced changes to the devices' static magnetic configuration. There are however potential advantages to be gained from using field dependent, high frequency magnetization dynamics for magnetic particle detection. Here we demonstrate the use of nano-confined ferromagnetic resonances in periodically patterned magnetic films for the detection of adsorbed magnetic particles with diameters ranging from 6 nm to 4 $\mu$m. The nanopatterned films contain arrays of holes which can act as preferential adsorption sites for small particles. Hole-localized particles act in unison to shift the resonant frequencies of the various modes of the patterned layer with shift polarities determined by the localization of each mode within the nanopattern's repeating unit cell. The same polarity shifts are observed for a large range of coverages, even when hole-localized particles are covered by quasi-continuous particle sheets. For large particles however, preferential adsorption no longer occurs, leading to resonance shifts with polarities which are independent of the mode localization. Analogous shifts are seen in continuous layers where, for small particles, the shift of the layer's fundamental mode is typically about 10 times less than in patterned systems and induced by relatively weak fields emanating beyond the particle in the direction of the static applied field. This highlights the importance of having confined modes consistently positioned with respect to nearby particles.

Highly Sensitive Detection of Catalase Modified Magnetic Nanoparticle Using Signal-Off ECL Imaging of Multichamber Electrode

Introduction Electrochemiluminescence (ECL) is the chemical luminescence reaction catalyzed by electrochemically active species. In the case of luminol-based ECL, the oxidation of luminol at the electrode and the reactive oxygen species (ROS) as coreactant result in excited intermediate and the release of photon upon relaxation. ECL is used in immunoassay and nucleic acid studies for its advantages such as low background and requiring no external light source. Many of these studies use H2O2 as target or coreactant since many biologically relevant events involve H2O2 and the results are often analyzed by the increase in ECL intensity. Particularly, many enzyme-based ECL that targets H2O2 are reported to date. In this study, catalase enzyme was used to take advantage of its fast turnover rate. However, use of enzymes are sometimes troublesome due to spontaneous reaction upon mixture containing enzyme and its substrate. We addressed this issue by generating substrate for enzyme that utilizes oxygen derivatives at electrode surface by oxygen reduction reaction (ORR). Also, magnetic nanoparticles are used for collection of target species to electrode proximity to elicit concentration effect. Therefore, combination of ORR-ECL and magnetic nanoparticles provide powerful tool for highly sensitive detection system. In this study, we report signal-off ECL using enzyme modified magnetic beads and electro-generated substrate reaction on a small volume multi-chamber screen printed electrode. Materials and Method Catalase enzyme was coupled to NHS modified magnetic nanoparticle (φ200 nm, Tamagawa Seiki) and the absorption spectra and enzyme activity of catalase modified magnetic nanoparticle (CAT-MB) were evaluated using spectroscopic method. For ECL measurement, screen printed electrode with 73 chambers (diameter 200 μm x height 10 μm) was used to limit the reaction volume to about 300 pL. Chambers were filled with solution containing CAT-MB and luminol and magnetic nanoparticles were attracted to the electrode surface using external magnet. Cover glass was placed on top of the electrode chip to cover the chambers to prevent diffusion of enclosed species. The substrate for catalase was electro-generated at the electrode surface. Constant negative potential was applied during the pretreatment time thereby generating ROS. ECL of chambers were recorded with image intensifier and electron magnifying CCD camera mounted on upright microscope. The enclosed catalase enzymes catalyzed H2O2 thus diminish of ECL intensity was observed with increasing magnetic particle concentrations. Electro-generation of ROS species on electrode surface was evaluated with various conditions including electrode pretreatment potential and pretreatment time to control the amount of ROS formed. Results and Discussion Spectroscopic characterization revealed absorbance peak shift from 280 nm to 220 nm from free catalase in aqueous phase to CAT-MB, respectively. Enzyme activity of CAT-MB was found to be lowered by factor of 10 compared to calculated value and the detection limit of CAT-MB was 0.2 μg/mL. The reduced enzyme activity was attributed to the structural modification of catalase molecule during the modification process. ROS electro-generation conditions were investigated by changing the pretreatment potential and time. Starting potential of CV sweep was changed from -1000 to 0 mV with 100 mV interval and the observed ECL intensity showed exponential reduction as the starting potential moved to more positive. Pretreatment time of 20 to 60 seconds were tested at various pretreatment potential and the ECL imaging at -500 mV showed clear difference in brightness at different pretreatment time conditions. The effect of bare magnetic nanoparticles and the use of external magnet on ECL response was also tested. Quantitative ECL imaging analysis using different concentrations of CAT-MB showed that this system can detect 1 ng/mL of magnetic nanoparticle on a multi-chamber chip, and each chamber was estimated to contain average of 5 magnetic nanoparticles. Conclusion In summary, this study successfully developed highly sensitive enzyme modified magnetic particle detection system using the combination of small volume multi-chamber electrode and magnet nanoparticles. Detection was conducted by observing the reduction of ECL signal caused by decomposition of H2O2 electro-generated at the electrode surface by catalase modified on the magnetic nanoparticles enclosed in small chambers. Difference in ECL signal with few nanoparticles as low as average of 5 magnetic nanoparticles in a chamber was detected.