Fiber Optic Spectrometer Research Articles

Research of Online Water Quality Monitoring System Based on Zigbee Network

For the characteristics of time consuming, complicated steps and lack of automatic of the traditional water quality monitoring, an automated real-time online water quality monitoring program based on wireless sensor network (WSN) is presented in this paper. This system combined micro-UV-Vis Fiber Optic Spectrometer with ZigBee Wireless Communication Technique to constitute Wireless Sensor Network Node which is placed at the monitoring water,and then used the ZigBee protocol’s real-time transmission and monitor data to raise the automation and monitoring level. This paper discussed the network architecture based on ZigBee protocol, maked design of Optical System of sensor node and the hardware and software and then maked spectroscopy signal real time collection and communication test. The experiment results show that the industrial monitoring system of water quality has few transmission errors, better anti-jamming ability, small size of sensor node, fast inspection speed. All these features are suitable for real-time and continuous monitoring the pollution level of industrial sewage.

Nanohole-Based Surface Plasmon Resonance Instruments with Improved Spectral Resolution Quantify a Broad Range of Antibody-Ligand Binding Kinetics

We demonstrate an affordable low-noise surface plasmon resonance (SPR) instrument based on extraordinary optical transmission (EOT) in metallic nanohole arrays and quantify a broad range of antibody-ligand binding kinetics with equilibrium dissociation constants ranging from 200 pM to 40 nM. This nanohole-based SPR instrument is straightforward to construct, align, and operate, since it is built around a standard microscope and a portable fiber-optic spectrometer. The measured refractive index resolution of this platform is 3.1 × 10(-6) without on-chip cooling, which is among the lowest reported for SPR sensors based on EOT. This is accomplished via rapid full-spectrum acquisition in 10 ms followed by frame averaging of the EOT spectra, which is made possible by the production of template-stripped gold nanohole arrays with homogeneous optical properties over centimeter-sized areas. Sequential SPR measurements are performed using a 12-channel microfluidic flow cell after optimizing surface modification protocols and antibody injection conditions to minimize mass-transport artifacts. The immobilization of a model ligand, the protective antigen of anthrax on the gold surface, is monitored in real-time with a signal-to-noise ratio of ~860. Subsequently, real-time binding kinetic curves were measured quantitatively between the antigen and a panel of small, 25 kDa single-chain antibodies at concentrations down to 1 nM. These results indicate that nanohole-based SPR instruments have potential for quantitative antibody screening and as a general-purpose platform for integrating SPR sensors with other bioanalytical tools.

Determination of optical coefficients of biological tissue from a single integrating-sphere

The detection of interactions between light and tissue can be used to characterize the optical properties of the tissue. The development is described of a method that determines optical coefficients of biological tissue from a single optical reflectance spectrum measured with an integrating-sphere. The experimental system incorporated a DH-2000 deuterium tungsten halogen light source, a USB4000-VIS-NIR miniature fiber optic spectrometer and an integrating-sphere. Fat emulsion and ink were used to mimic the scattering and absorbing properties of tissue in the tested sample. The measured optical reflectance spectrums with different scattering and absorbing properties were used to train a back-propagation neural network (BPNN). Then the neural network (BPNN) was used to determine the optical coefficients of biological tissue from a single optical reflectance spectrum measured with an integrating-sphere. Tests on tissue-simulation phantoms showed the relative errors of this technique to be 7% for the reduced scattering coefficient and 15% for the absorption coefficients. The optical properties of human skin were also measured in vivo.

椎弓根钉植入针道上骨组织光谱特性研究

The characteristic identification factor of the vertebra at different positions was studied by spectroscopic technology.The spectral measurement system consists of computer,the integrated hand drill with dual-fiber probe(each fiber′s core diameter is 200 μm and the distance between the center of two fibers is 0.5 mm),halogen light source(wavelength is from 360 nm to 2 000 nm) and fiber optic spectrometer(detection wavelength: 200～1 100 nm).The diffuse reflectance spectrum and the reduced scattering coefficient of biological tissue could be obtained at the same time.Pig′s vertebra was chosen as experimental subject to measure the diffuse reflectance spectrum and scattering coefficient of different bone tissue on pedicle screw placement pathway.The characteristic identification factor was defined by analyzing the peak values,the size of the area and the slope of the spectrum in specific wavelength.We find that different bone tissue′s spectrums show different characteristics.The change of the peak values was 1.77 and the change of the area values was 2.13 times higher than that of scattering coefficient,respectively.At the range of 495 nm to 505 nm,the slope of spectrum of cortical bone and cancellous bone was positive.At the range of 520～535 nm,the slope of spectrum of cortical bone was positive,and the slope of cancellous bone was negative.It can be concluded that the peak value,the area and the slope obtained by analysis of spectrum′s characteristics could distinguish the difference between cortical bone and cancellous bone.

Thiourea functionalized hydrogel photonic crystal sensor for Cd2+ detection

A new hydrogel photonic crystal (HPC) sensor utilizing thiourea as the recognition group for cadmium cation detection was developed. The sensor was fabricated by infiltrating a 3D contact polystyrene photonic crystal template with precursor solution of acrylamide, 1-allyl-2-thiourea and N,N′-methylenebisacrylamide, followed by a thermal polymerization using ammonium persulfate as initiator at room temperature. The resulting HPC sensor with periodic opal structure changed its volume and Bragg diffraction wavelength in response to the difference of the Cd2+ concentration. Shifts of diffraction peak were observed by using a fiber optic spectrometer and the measurements showed a function relationship between the blue-shift and aqueous Cd2+ concentrations in the range of 0.01 mmol L−1 to 10 mmol L−1 in a pH 4 buffer solution. The functionalized thiourea groups allowed HPC to recognize the analyte Cd2+ with high specificity. The maximum blue-shift reached 47 nm responding to Cd2+ but no significant shift responding to Zn2+ and Hg2+. The HPC sensor could be used to quantitatively determine Cd2+ concentrations in complex solutions such as natural water.

Wide field-of-view imaging spectrometer using imaging fiber bundles

A field-of-view-folding approach is proposed to extend the field of view (FOV) of a dispersive imaging spectrometer after introducing several linear arrays of imaging fiber bundles to which to replace the slit. The fiber bundles can flexibly connect fore-optics with a spectrometer to yield an imaging fiber-optic spectrometer (IFOS). The technology of FOV segmenting and folding, which can decrease simultaneously the dimension and spectral distortion of the imaging spectrometer, is described in detail. Because of the sampling function of the fiber bundles, the IFOS is a double-sampling imaging system. We analyze the effect of fiber coupling on the modulation transfer function (MTF) and then develop a cascade MTF model to estimate the imaging performance of the IFOS. A spaceborne IFOS example is presented to describe how the method can be used.

FPGA-Based Micro Fiber-Optic Spectrometer Hardware Circuit System

Portability has become an inevitable trend of spectrometer. Faced with the trend, one micro fiber-optic spectrometer hardware circuit system, which regarded XC3S250E as master chip to control CCD scan, A/D conversion and USB data transmission, etc, was designed, and the corresponding circuits were designed. After consecutive spectral scan test, we can find that the designed spectrometer is able to complete the acquisition, conversion and transmission of spectrum. The system stability is very good and the scanning accuracy can reach 1nm.

Rapid In Situ Repeatable Analysis of Drugs in Powder Form Using Reflectance Near‐Infrared Spectroscopy and Multivariate Calibration

This study takes the first step toward in situ analysis of powder drugs which does not require any alteration of the samples. A fast, inexpensive analytical method based on reflectance near-infrared (NIR) spectrometry and multivariate calibration was applied. A diode-array fiber-optic portable spectrometer in the 900-1700 nm range was employed. Samples were laboratory-prepared ternary powders (diacetylmorphine, caffeine, and paracetamol). Partial least squares regression was applied. The choice of the standard samples for calibration and validation was performed through a D-optimal experimental design. The explained variance was higher than 90%, and the relative root mean square errors were <2%. The number of principal components (6) was very low when compared with the number of raw variables (356 absorbance values). Response plots showed slopes and intercepts were very close to optimal values. Correlation coefficients ranged between 0.909 and 0.989. The method here proposed proved to be competitive with Fourier transform NIR spectrometry.

Study on Quantitative Detection of Pesticide Residue Based on Spectroscopy Technology of Differential Absorption

For the domestic food safety problem that caused by the pesticide residues in food, it’s very important to find a convenient and cost-appropriate detection technology. At present, spectroscopy absorption technology has been used for detection of pesticide residues in food. However, there are some deficiencies such as the quantitative detection and the measurement precision. This experiment that based on differential absorption is completed by using miniature fiber optic spectrometer and spectrophotometer, and then the pesticide DDVP is also measured quantitatively. Thus the pesticide residue detection technology that based on spectroscopy absorption is improved to adjust to the practical application.

Battery-operated, argon–hydrogen microplasma on hybrid, postage stamp-sized plastic–quartz chips for elemental analysis of liquid microsamples using a portable optical emission spectrometer

A battery-operated, atmospheric pressure, self-igniting, planar geometry Ar-H(2) microplasma for elemental analysis of liquid microsamples is described. The inexpensive microplasma device (MPD) fabricated for this work was a hybrid plastic-quartz structure that was formed on chips with an area (roughly) equal to that of a small-sized postage stamp (MPD footprint, 12.5-mm width by 38-mm length). Plastic substrates were chosen due to their low cost, for rapid prototyping purposes, and for a speedy microplasma device evaluation. To enhance portability, the microplasma was operated from an 18-V rechargeable battery. To facilitate portability even further, it was demonstrated that the battery can be recharged by a portable solar panel. The battery-supplied dc voltage was converted to a high-voltage ac. The ~750-μm (diameter) and 12-mm (long) Ar-H(2) (3% H(2)) microplasma was formed by applying the high-voltage ac between two needle electrodes. Spectral interference from the electrode materials or from the plastic substrate was not observed. Operating conditions were found to be key to igniting and sustaining a microplasma that was simply "warm" to the touch (thus alleviating the need for cooling or other thermal management) and that had a stable background emission. A small-sized (900 μL internal volume) electrothermal vaporization system (40-W max power) was used for microsample introduction. Microplasma background emission in the spectral region between 200 and 850 nm obtained using a portable fiber-optic spectrometer is reported and the effect of the operating conditions is described. Analyte emission from microliter volumes of dilute single-element standard solutions of Cd, Cu, K, Li, Mg, Mn, Na, Pb, and Zn is documented. The majority of spectral lines observed for the elements tested were from neutral atoms. The relative lack of emission from ion lines simplified the spectra, thus facilitating the use of a portable spectrometer. Despite the relative spectral simplicity, some spectral interference effects were noted when running a multi-element solution. An example of how interference in the spectral domain can be resolved in the time domain using selective thermal vaporization is provided. Analytical utility and performance characteristics are reported; for example, K concentrations in diluted (~30 times) bottled water were determined to be 4.1 ± 1.0 μg/mL (4 μg/mL was the stated concentration), precision was about 25%, and the estimated detection limits were in the picogram range (or in nanograms per milliliter in relative units).

Application of miniature spectrometer in liquid signature analysis technology

A spectral liquid signature analyzer system including a miniature fiber-optic spectrometer is described in this paper. Through the combination of the spectral method and liquid signature analysis technology, the analytical function of the liquid signature analyzer will be improved obviously. With this spectral liquid signature analyzer system, the physical, chemical, and mechanical characteristics of the tested sample can be obtained at the same time. In detail, that is the light intensity signal, the equivalent drop volume signal, and the spectroscopic data from the miniature spectrometer. And after merging the information data, the three-dimensional fingerprint that is unique to the liquid sample is attainable. This three-dimensional fingerprint includes the full information we gain from the experiment, and it provides visualized differences in various samples. The application of spectral analysis makes it possible for further research into the chemical compositions of liquid samples and supplies discrimination evidence to different liquids. Therefore, the liquid signature analyzer can be used in more fields related to liquid.

Measurement of Diffuse Reflectance Spectrum of Biological Material with Single Integrating-Sphere

Detection of interactions between light and biological material can be used to characterize the optical properties of the biological material. The purpose of this paper is to develop a method that measures the diffuse reflectance spectrum of biological material with single integrating-sphere. The experimental system incorporated a DH-2000 Deuterium Tungsten Halogen Light Sources, USB4000-VIS-NIR Miniature Fiber Optic Spectrometer and an integrating-sphere. Intralipid and ink were used to mimic scattering and absorbing properties of biological material in the tested sample. Total of 30 sample representing of normal and malignant human breast tissue were measured. The measured optical reflectance spectrums with different scattering and absorbing properties were analyzed. The result showed that the diffuse reflectance spectrums of normal and malignant biological material are different in intensity.

FEASIBILITY OF USING A MINIATURE FIBER OPTIC UV‐VIS‐NIR SPECTROMETER TO ASSESS TOTAL POLYPHENOL INDEX, COLOR INTENSITY AND VOLUMIC MASS IN RED WINE FERMENTATIONS

ABSTRACT This study sought to assess the feasibility of using ultraviolet‐visible‐near infrared (UV‐VIS‐NIR) spectroscopy to monitor changes in total polyphenol index, color intensity and volumic mass, three indicators of quality during red wine fermentation. Samples (n = 68) collected from eleven tanks during fermentation were scanned in three types of quartz flow cells, path lengths 0.1, 2 and 50 mm, in the UV‐VIS‐NIR region (200–1,100 nm), using a fiber spectrometer system in transmission mode. Principal component analysis and partial least squares regression were used to interpret spectra and develop calibrations for predicting wine composition during fermentation. Models for the prediction of total polyphenol index displayed coefficients of determination (r2) ranging between 0.21–0.98, whereas values for the standard error of cross‐validation (SECV) ranged from 2.29 to 14.91, depending on the spectral region used. Values for the prediction of color intensity were: r2 = 0.56–0.98 and SECV = 0.43–1.88. Corresponding values for volumic mass were r2 = 0.31–0.94 and SECV = 8.71–30.20 g/dm3. These results suggest that UV‐VIS‐NIR spectroscopy using a miniature fiber optic spectrometer as a promising tool could be used as an alternative method for the rapid monitoring of quality parameters during red wine fermentation.PRACTICAL APPLICATIONSThe study develops ultraviolet‐visible‐near infrared calibrations to monitor changes in total polyphenol index, color intensity and volumic mass, main indicators of quality during red‐wine fermentation, taking into account and responding to the requirements of the enological industry that looks for a swift, efficient, economical and – particularly – nondestructive analytical technique for measuring quality parameters during fermentation process with a single instrument and in a matter of seconds, saving time and enhancing the decision‐making process. The work also evaluates the efficacy of a simple, efficient and low‐cost instrument that belongs to so called new near infrared spectroscopy (NIRS) generation, which are most suitable to be implemented for on‐line analysis in the winemaking industry. The results suggest that the miniature fiber optic NIR spectrometer is a promising tool for monitoring the red wine fermentation process, allowing the instantaneous prediction of the main parameters to be controlled. At the same time, suitable wavelengths for these parameters are also proposed according to x‐loading weights and regression coefficients.

Performance Improvement in Fiber-Optic Spectrometers Using Photonic Crystal Fibers

Resolution enhancement of a high-speed fiber-optic spectrometer is investigated in this article. The operation of these types spectrometers is based on conversion of the spectral-domain signal into the time domain by a dispersive element. A photonic crystal fiber is used as a dispersive fiber in this spectrometer. Resolution enhancement of considered spectrometer with photonic crystal fibers is studied. The fiber loss and length minimization in this spectrometer are obtained. Simulation results show that an increase in resolution will cause a decrease in the speed of the spectrometer. Trade offs between resolution and speed are studied.

Surface Modification of TiO&lt;sub&gt;2&lt;/sub&gt; Nanopaticles with Good Reflective Properties for Electric Ink

To obtain the microencapsulated electric ink with good display properties, the bare TiO2 nanoparticles were modified by stearic acid (SA), and the white encapsulated electric ink was prepared by complex coacervation using Gelatin/gum arabic (GA) as wall materials. The bare and modified TiO2 nanoparitcles were characterized by SEM. Moreover, the fiber-optic spectrometer was also used to measure the reflective properties of the two particles. It was shown that the aggregation phenomena can be greatly decreased by surface modification, and also that the reflective properties can be maintained by this method. Finally, the particles in microcapsules possessed reversible response to dc electric field, and the response time was ~150 ms.

Birefringence dispersion in a quartz crystal retrieved from a channeled spectrum resolved by a fiber-optic spectrometer

We present a simple method for measuring the wavelength dependence of both the phase and group birefringences in a quartz crystal of known thickness. The method utilizes interference of polarized waves resolved by a fiber-optic spectrometer as a channeled spectrum (spectral fringes). The fringe order versus the precise position of the interference maximum in the spectrum is fitted to the approximate function, from which the phase birefringence as a function of wavelength is retrieved. We also determine the group birefringence dispersion. The functions measured in a range from 500 to 900 nm are compared with those resulting from the available dispersion relation, and very good agreement is confirmed.

Study and implementation of a hybrid diffractive/refractive lens and a color inkjet head on high density data storage

Traditional optical storage technology focuses a laser beam on the surface of a disk using objective lenses. The storage capacity is limited. It entirely depends on the effective disk size. Using colored storage technology to increase the storage capacity is a novel approach. Color is used to store information. After the spectrometer reads the data, the original color is computed and the stored information is read. In this study, a color is used to write colors; optical transmission with a hybrid diffractive/refractive lens produces a transmission spectrum, and then the fiber-optic spectrometer reads and analyzes the color and then decodes the information. Based on a 2.4 μm reading spot size and the implementation of tricolor ink, ∼4.561 Gbytes can be stored. If the tricolor ink dripping and laser size can be reduced to 1.80 μm, each disk can store data up to 8.1 GB.

Colourimetric solid‐phase extraction coupled with fibre optic reflectance spectroscopy for determination of ascorbic acid in pharmaceutical formulations

A redox colourimetric solid-phase extraction (C-SPE) procedure for the determination of ascorbic acid (AA) in pharmaceutical formulations was proposed. Iron (III)-2,2'-dipyridyl (Fe(III)-Bpy) reagent solution was used as a colouring reagent for AA and the immobilization of the redox product onto Amberlite XAD-16 resin was achieved. The analyte in the sample reacted with a solid sorbent loaded with the colourimetric reagent (Fe(III)-Bpy) and then quantified directly on the sorbent surface by using a fibre optic reflectance spectrometer (FORS). The amount of AA was reflectometrically determined in a few seconds with a total sample workup and readout time of ∼10 min using only 10-ml sample volumes. The limit of detection (LOD) and quantification (LOQ) values were 0.18 and 0.6 mg L(-1), respectively, and the linear dynamic range for AA extended up to 8.8 mg L(-1). The C-SPE for different extractions (n = 5) gave a relative standard deviation (RSD) of 2.9% at 5.28 mg L(-1) AA level.

Inexpensive Green Method for Diclofenac Assay Utilizing Sequential Injection Chromatography

Sequential injection chromatography (SIC) is a recent inexpensive miniaturized separation technique. The current manuscript reported the development of a new SIC method for the assay of diclofenac in pharmaceutical formulations. Chemometrics was exploited for the first time to optimize SIC methodology. The 23 full-factorial design was adopted to screen the effect of mobile phase composition, sample volume, and flow rate on retention time and peak height. The optimum chromatographic conditions were: C18 monolithic column (25 × 4.6 mm); mobile phase composition methanol:water (50:50, v/v), sample volume 60 μL, flow rate 40 μL s−1. The detection was carried out using a miniaturized fiber optic spectrometer set at 284 nm. Satisfactorily, separation was achieved in 0.92 min with the number of theoretical plates of >180,000 and peak symmetry 1.21. The method enjoyed good precision with relative standard deviation values for intra- and inter-day precision of 1.47 and 2.15%, respectively. The use of large sample volume rendered the method sensitive with the limits of detection and quantification of 0.32 and 1.07 μg mL−1, respectively. The remarkable advantages of the method are high rapidity (sample frequency 23 sample h−1) and reagent saving (total consumed volume 3.0 mL) and thus better safety for the environment.

Heat treatment of human esophageal tissues: Effect on esophageal cancer detection using oxygenated hemoglobin diffuse reflectance ratio

The main objective of the present work is to study the influence of heat treatment on the esophageal cancer detection using the diffuse reflectance (DR) spectral intensity ratio R540/R575 of oxygenated hemoglobin (HbO2) absorption bands to distinguish the epithelial tissues of normal human esophagus and moderately differentiated esophageal squamous cell carcinoma (ESCC) at different heat treatment temperature of 20, 37, 42, 50, and 60°C, respectively. The DR spectra for the epithelial tissues of the normal esophagus and ESCC in vitro at different heat-treatment temperature in the wavelength range 400–650 nm were measured with a commercial optical fiber spectrometer. The results indicate that the average DR spectral intensity overall enhancement with concomitant increase of heat-treatment temperature for the epithelial tissues of normal esophagus and ESCC, but the average DR spectral intensity for the normal esophageal epithelial tissues is relatively higher than that for ESCC epithelial tissues at the same heat-treatment temperature. The mean R540/R575 ratios of ESCC epithelial tissues were always lower than that of normal esophageal epithelial tissues at the same temperature, and the mean R540/R575 ratios of the epithelial tissues of the normal esophagus and ESCC were decreasing with the increase of different heat-treatment temperatures. The differences in the mean R540/R575 ratios between the epithelial tissues of normal esophagus and ESCC were 13.33, 13.59, 11.76, and 11.11% at different heat-treatment temperature of 20, 37, 42, and 50°C, respectively. These results also indicate that the DR intensity ratio R540/R575 of the hemoglobin bands is a useful tool for discrimination between the epithelial tissues of normal esophagus and ESCC in the temperature range from room temperature to 50°C, but it was non-effective at 60°C or over 60°C.