Principles and analytical applications of acousto-optic tunable filters, an overview

Advantages of acousto-optic tunable filters have been exploited to develop novel analytical instruments which are not feasible otherwise. The instrumentation development and unique features of such AOTF based instruments including the multidimensional fluorimeter, the multiwavelength thermal lens spectrometer, the near-infrared spectrometer based on erbium doped fiber amplifier (EDFA), and detectors for high performance liquid chromatography (HPLC) and flow injection analysis (FIA), will be described.     

Fluorescence studies of carbocyanines using AOTF

Over the past few years acceptance of acousto-optic devices which can control optical radiation has increased. In this paper the use an acousto-optic tunable filter (AOTF) within an existing spectrofluorometer as a replacement for the excitation monochromator is reported. Long wavelength absorbing carbocyanine dyes that have strong absorption and high quantum yield are used as standards. The major advantage of using an AOTF filter is the wavelength purity and that it can act as a wavelength selector in place of a monochromator. The use of AOTF in place of bandpass filters for removing laser diode side bands is also discussed.     

AOTF-based multicolor fluorescence detection for short tandem repeat (STR) analysis in an electrophoretic microdevice

An acousto-optic tunable filter (AOTF) has been used to perform multicolor fluorescence detection for four and five-color short tandem repeat (STR) analysis on glass microchips. Matrix files were initially generated by collecting and comparing the laser-induced fluorescence emission of the labels specific to a particular STR kit, and raw data was processed to remove spectral overlap. The AmpFlSTR kits used in this work include Profiler Plus and COfiler, which are four-color kits used in tandem to address the core STR loci, as well as the five-color Identifiler kit, which contains each of the loci. In contrast to previous reports on multicolor detection for STR analysis on microchips, this detection system is characterized by a single filter and detector, and reports the first five-color genotyping application on-chip. This capability matches the portability and reduced scale of the microchip with the state-of-the-art in multicolor STR analysis kits.     

A compact collinear AOTF Raman spectrometer

A compact, lightweight, completely packaged, uncooled, fully-automated collinear acousto-optic tunable-filter (AOTF) based spectrometer has been used to measure Raman spectra of three organic energetic materials (NQ, HMX, and TNT) using argon-ion laser excitation. Even though the resolution of the AOTF spectrometer is modest (7.4 cm(-1)) and it was not specifically designed for measuring Raman spectra, it has performed impressively. Such an instrument is specially useful for remote sensing and field measurements. In this paper, we will describe this instrument, present the measured Raman spectra and their comparison with the corresponding FT-IR spectra.     

Rheo-optical near-infrared (NIR) spectroscopy study of low-density polyethylene (LDPE) in conjunction with projection two-dimensional (2D) correlation analysis

A rheo-optical characterization technique based on near-infrared (NIR) spectroscopy is developed specifically to probe the submolecular-level deformation caused during a mechanical test. An illustrative example of the mechanical deformation of low-density polyethylene (LDPE) is provided to show how it can be utilized. A set of NIR spectra of the polymer sample were collected by using an acousto-optic tunable filter (AOTF) NIR spectrometer coupled with a tensile testing machine as an excitation device. While the substantial level of variation of spectral intensity was readily captured during the mechanical deformation of the LDPE, main feature of the NIR spectra was overwhelmed by the contribution from the baseline change. Projection 2D correlation analysis was then applied to selectively extract the signal contribution from the baseline fluctuation. The 2D correlation spectra revealed the predominant extension of amorphous tie chains followed by the rotation of crystalline lamellae, which induce elastic and plastic deformation of the LDPE, respectively.     

声光可调滤光片表面等离子体子共振传感器的研究

自行设计并组装了一套以声光可调滤光片(AOTF)为波长选择系统的波长检测型表面等离子体子共振(SPR)传感器装置,介绍了AOTF的特点和性能.研究了传感器对乙醇、葡萄糖和蔗糖的响应特性,三者的线性范围分别为5%～60%(体积分数),0.028～0.280和0.014～0.140mol/L.并对葡萄糖和蔗糖的混合溶液进行了分析.实际样品的测定结果与国家标准方法的测定值相符合     

Tensile deformation of isotactic polypropylene (iPP) and iPP-nanocomposite studied by rheo-optical near-infrared (NIR) spectroscopy

Tensile deformations of isotactic polypropylene (iPP) and its nanocomposite were examined by a rheo-optical characterization technique based on near-infrared (NIR) spectroscopy to derive the submolecular-level understanding of the deformation mechanism during a tensile test. Sets of NIR spectra of the iPP samples were collected by using an acousto-optic tunable filter (AOTF) NIR spectrometer coupled with a tensile testing machine as an excitation device. Mechanical deformation of the samples was readily captured as strain-dependent NIR spectra. However, the main feature of the NIR spectra was overwhelmed by the contribution from the baseline change due to the substantial decrease in the sample thickness and subsequent change in the NIR light scattering. The variation of the spectral feature suggests that the deformation of the iPP involves the elongation of the rubbery amorphous chains prior to the displacement of the crystalline lamellae, providing elastic and subsequent plastic deformations during the tensile testing. In addition, it is revealed that the nanoclay layers dispersed within the iPP matrix restrict the elongation of the amorphous chains. Such interaction makes iPP hard and brittle, so that it yields no obvious ductile fracture during the tensile deformation.     

Concurrent hypermulticolor monitoring of CD31, CD34, CD45 and CD146 endothelial progenitor cell markers for acute myocardial infarction

The circulating endothelial progenitor cells (EPCs) in blood of acute myocardial infarction (AMI) patient have been monitored in many previous studies. The number of circulating EPC increases in the blood of patients at onset of the AMI. EPC is originated from bone marrow. It performs vessel regeneration. There are many markers used for detecting EPC. Four of these markers, CD31, CD34, CD45, and CD146, were concurrently detected at the single cell level for the identification of EPC in the present preliminary study. The CD45 negative cell sorting was performed to peripheral blood mononuclear cells (PBMCs) acquired from four AMI patients with a magnetic bead sorter, since, EPCs expressed CD45 negative or dim. The resultant PBMC eluents were treated with quantum-antibody conjugates for the probing four different markers of EPCs and then applied to a high-content single cell imaging cytometer using acousto-optical tunable filter (AOTF). The use of quantum dot, with narrow emission wavelength range and AOTF enabling cellular image at a particular single wavelength, is very advantageous for accurate high-content AMI diagnosis based on simultaneous monitoring of many markers. The number of EPC increased as compared with control in three of four AMI patients. In this approach, two EPC subtypes were found, CD31(+), CD34(+), CD45(−/dim), CD146(−) as early outgrowth EPCs and CD31(+), CD34(+), CD45(−/dim), CD146(+) as late outgrowth EPCs. Patient 1 had CD31(+), CD34(+), CD45(−/dim), CD146(+) cells whose percentage was 4.21% of cells. Patient 2 had 2.38% of CD31(+), CD34(+), CD45(−/dim), CD146(−) cells and patient 3 had 4.28% of CD31(+), CD34(+), CD45(−/dim), CD146(+) cells.     

Stand-off Raman detection using dispersive and tunable filter based systems

Small, transportable Raman systems are being developed for stand-off Raman measurements at intermediate ranges (e.g. <20 m) for planetary measurements. Four variations of stand-off Raman systems are described that use a small telescope for light collection that is either fiber-optic or lens-coupled to a detection system. The performance of an acousto-optic tunable filter for wavelength selection and spectral imaging is tested by comparing signal-to-noise ratio and throughput to similar measurements using a conventional spectrograph, and by measuring a variety of organic and inorganic mineral samples at distances up to 15 m. We also determine optimal ICCD gate widths for acquiring remote Raman spectra under high ambient light conditions.     

Bienzyne Electrodes for ATP,NAD+, Starch and Disaccharides Based on a Glucose Sensor

Abstract

A glucose measuring device based on the oxidation of glucose by glucose oxidase and an amperometric kinetic detection was developed. The characteristics obtained with this instrument are comparable with the present glucose instruments but the stability of the enzyme membrane is better and the measuring frequency is higher. In order to expand the applicability of this device to other substrates there was developed a family of bioenzyme electrodes. Enzymes producing glucose as enzymes consuming glucose in addition to glucose oxidase were used.

For determination of peroxidase substrates besides a peroxidase-catalase electrode a three-enzyme system consisting of glucose oxidase, peroxidase and catalase was used.     

Use of an Imaging Spectrograph System with a Fiber Optical Sensor and Two Dimensional Cooled Ccd Detector For Solid Surface Room Temperature Phosphorescence of Pesticides

ABSTRACT

This paper presents a development of a fiber optic sensor for solid surface room temperature phosphorescence of pesticides. The system is based on an imaging spectrograph coupled with a cooled two-dimensional charge coupled device detector. An optimization approach using a different mode of reading out data, the effects of moisture in solid matrix phosphorescence and the effects of heavy atoms are discussed. Spectral characterizations on Whatman N⁰1 filter papers of Warfarin, Naptalam, and naphthalene-type pesticides were evaluated. Limits of detection at ng to pg levels were estimated for all compounds. Satisfactory reproducibility of measurements was observed. The standard addition method was used to determine concentrations of Warfarin and Naptalam pesticides present together in a mixture. Results obtained show the potential of the device for the quantitative analysis of environmental pollutants.     

Determination of water contents in leaves by a near-infrared multispectral imaging technique

The kinetics of water desorption from olive leaves was studied using a near-infrared (NIR) multispectral imaging spectrometer. This imaging spectrometer is capable of sensitively and rapidly recording NIR spectral images of leaves because it was constructed with an acousto-optic tunable filter and an InGaAs focal plane array NIR camera. The high sensitivity and fast scanning ability of the imaging spectrometer make it suitable for kinetic determination. The kinetics of water desorption from olive leaves, determined by this multispectral imaging instrument, show that rate of water desorption is strongly dependent on the environment in which the leaves were stored. Water desorbed from leaves faster when leaves were stored under dry conditions. The rate for leaves stored in 0% humidity environment is 1.5× faster than those stored in 50% humidity.     

Bioanalysis of Naproxen by High Performance Reversed Phase Liquid Chromatography with Photometric and Fluorimetric Detection

Abstract

Methods for the quantitative determination of NAPROXEN and its main metabolite in plasma and urine are described. The separation is based on reversed phase liquid chromatography with LiChrosorb RP 8 (5 μm) as the support and methanol/phosphate buffer pH 7 as mobile phase, in some cases with addition of tetrabutyl ammonium ion as ion-pairing agent to improve the chromatographic selectivity. With UV-detector and a simple filter fluorometer an extraction-evaporation procedure is used for both plasma and urine determinations, while the high selectivity and sensitivity of a sophisticated fluorescence detector permits the direct injection of diluted samples on to the column. Use of an internal standard improves the within-run precision (s_rel%), which for plasma determinations of NAPROXEN are - with UV-detection, 0.2 – 1.7% (range 10 – 40 μg/ml), with filter fluorometer, 2.4 – 5.9% (range 12 – 58 μg/ml), and with fluorescence detector, 0.8 – 4.1% (range 5 – 20 μg/ml).     

Spectrophotometric Determination of Chromium(VI) with Cr(VI)-o-Cl-PF–TDPC Ternary Complex after Preconcentration on an Organic Solvent-soluble Membrane Filter

Abstract

A simple and rapid preconcentration technique, based on collecting trace hexavalent chromium on an organic soluble membrane filter is described. At pH 5.0, chromium(VI), o-chlorophenyl-fluorone (o-Cl-PF) and tetradecylpyridinium chloride (TDPC) form the ternary ion-associate chelate, which can be collected on a 0.2μm nitrocellulose membrane. The filter is dissolved in a small volume of dimethyl sulfoxide (DMSO) acidified with 0.15 mL 3 mol/L sulfuric acid, and the absorbance of the resulting solution is measured at 545 nm wavelength against the reagent blank. The absorbance is proportional to the content of hexavalent chromium in the range of 0.1–1.8μg, in 5 mL solvent. The sensitivity of the ternary complex reaction is very high with molar absorptivity of 1.2 × 10⁵. A detection limit better than 0.3 μg/L can be achieved. The ions normally present in water do not interfere when mixed masking agents are added. The proposed method has been applied to the analysis of water samples from several sources, the recoveries of the hexavalent chromium added to the samples are quantitative, and results found are satisfactory.     

Implications for Mercury Toxicity from the Structure of An Oxacalix[3]arene-HgCl 2 Complex?

t -Butyloxacalix[3]arene tris (diethylacetamide), known to mimic the cellular sodium ion selectivity filter, has been shown to bind HgCl 2 . The dimeric complex crystallises in the triclinic space group P 1 with a =17.3019(6) Å, b =18.7821(4) Å, c =19.9025(5) Å, ! =67.3010(10), # =77.664(2); % =77.238(2) and D c =1.370 g cm m 3 for Z =4. Refinement based on 37,818 observed reflections gave a final R value of 0.0483. Implications for routes of mercury uptake are discussed.     

Adverse Effects of Lag Filters Used for Detector Baseline Noise Suppression in High Performance Liquid Chromatography

Abstract

Most detectors used for High Performance Liquid Chromatography employ a lag filter for suppression of baseline noise. This filter is characterised by its time constant, τ. At high values of τ (in excess of 0.5 sec), the lag filter seriously distorts the shape of a chromatographic peak, causing reduced peak heights, altered retention times and increased peak width. These changes result in significantly decreased resolution and decreased plate counts. These effects are investigated quantitatively.     

异核双金属探针在活细胞细胞核和线粒体中选择性定位DNA

用于实时成像活细胞DNA的细胞核探针是非常罕见的。通过Ru(N^N)₃、Ir(C^N)₂(N^N)、Re(CO)₃Cl(N^N)和Pt(C^N)(N^N)的结合,生成了4种异核双金属配合物：2种不同的功能金属位点被锚定在线性双齿螯和配体(N^N)-(N^N)的尾端,形成不对称哑铃状的双金属分子M₁-M₂,即Ru-Re、Ru-Pt、Ir-Re和Ir-Pt。Ru-Re和Ru-Pt的红色发射探针具有较大的斯托克斯位移、优异的核膜穿透能力、良好光稳定性的DNA结合能力。此外,Ru-Re和Ru-Pt探针的DNA成像可与专门用于活细胞细胞核DNA染色的Hoechst 33342商用染料相媲美,而Ir-Re和Ir-Pt探针直接靶向线粒体。不同探针的发光特性和选择性胞内定位高度依赖于在异核双金属配合物中的金属物种。     

用于活体和细胞内SO2衍生物检测的线粒体靶向双光子磷光铱(Ⅲ)配合物

暴露于高剂量的二氧化硫（SO₂）及其衍生物（SO₃^2-和HSO₃^-）会导致血管疾病甚至肺癌发生。双光子磷光成像显微术（TPPIM）和双光子磷光寿命成像显微术（TPPLIM）具有良好的时空分辨能力、抗光漂白、抗自体荧光以及较强组织穿透性等优点,可以实现SO₂衍生物在生物样品中实时检测。得益于铱配合物的长磷光寿命（~110 ns）和线粒体靶向特性,本文报道了首例基于TPPLIM技术的SO₂衍生物检测探针Ir-EA。Ir-EA对水溶液中的亚硫酸氢盐表现出高特异性和灵敏性的识别能力（69倍磷光增强,10倍亚硫酸氢盐）和较低的检测限（65 nmol·L^-1）。更为重要的是,Ir-EA对活细胞和斑马鱼的线粒体中SO₂衍生物表现出良好的成像效果。     

Development and analytical applications of multispectral imaging techniques: an overview

A multispectral imaging spectrometer is an instrument that can simultaneously record spectral and spatial information of a sample. Chemical and physical properties of the sample can be elucidated from such images. By synergistic use of an acousto-optic tunable filter and a progressive scan camera capable of snap shot recording it was possible to develop a novel imaging spectrometer with a spatial resolution of a few microns and which can record, grab and store up to 33 images per second (at a function of time) or 16 images per second (as a function of wavelength). This overview article summarizes the instrumentation development of various imaging spectrometers and their applications including its use as the detector for the determination of identity and sequences of peptides synthesized by the combinatorial solid phase method.     

Development and analytical applications of multispectral imaging techniques: An overview

A multispectral imaging spectrometer is an instrument that can simultaneously record spectral and spatial information of a sample. Chemical and physical properties of the sample can be elucidated from such images. By synergistic use of an acousto-optic tunable filter and a progressive scan camera capable of snap shot recording it was possible to develop a novel imaging spectrometer with a spatial resolution of a few microns and which can record, grab and store up to 33 images per second (at a function of time) or 16 images per second (as a function of wavelength). This overview article summarizes the instrumentation development of various imaging spectrometers and their applications including its use as the detector for the determination of identity and sequences of peptides synthesized by the combinatorial solid phase method.