共查询到20条相似文献,搜索用时 250 毫秒
1.
Zachhuber B Ramer G Hobro A Chrysostom ET Lendl B 《Analytical and bioanalytical chemistry》2011,400(8):2439-2447
A pulsed stand-off Raman system has been built and optimised for the qualitative and quantitative analysis of inorganic and
organic samples including explosives. The system consists of a frequency doubled Q-switched Nd:YAG laser (532 nm, 10 Hz, 4.4 ns
pulse length), aligned coaxially with a 6″ Schmidt–Cassegrain telescope for the collection of Raman scattered light. The telescope
was coupled via a fibre optic bundle to an Acton standard series SP-2750 spectrograph with a PI-MAX 1024RB intensified CCD
camera equipped with a 500-ps gating option for detection. Gating proved to be essential for achieving high signal-to-noise
ratios in the recorded stand-off Raman spectra. In some cases, gating also allowed suppression of disturbing fluorescence
signals. For the first time, quantitative analysis of stand-off Raman spectra was performed using both univariate and multivariate
methods of data analysis. To correct for possible variation in instrumental parameters, the nitrogen band of ambient air was
used as an internal standard. For the univariate method, stand-off Raman spectra obtained at a distance of 9 m on sodium chloride
pellets containing varying amounts of ammonium nitrate (0–100%) were used. For the multivariate quantification of ternary
xylene mixtures (0–100%), stand-off spectra at a distance of 5 m were used. The univariate calibration of ammonium nitrate
yielded R
2 values of 0.992, and the multivariate quantitative analysis yielded root mean square errors of prediction of 2.26%, 1.97%
and 1.07% for o-, m- and p-xylene, respectively. Stand-off Raman spectra obtained at a distance of 10 m yielded a detection limit of 174 μg for NaClO3. Furthermore, to assess the applicability of stand-off Raman spectroscopy for explosives detection in “real-world” scenarios,
their detection on different background materials (nylon, polyethylene and part of a car body) and in the presence of interferents
(motor oil, fuel oil and soap) at a distance of 20 m was also investigated. 相似文献
2.
Graham AW Ray SJ Enke CG Barinaga CJ Koppenaal DW Hieftje GM 《Journal of the American Society for Mass Spectrometry》2011,22(1):110-117
A new instrumental concept, distance-of-flight mass spectrometry (DOFMS), is demonstrated experimentally. In DOFMS the mass-to-charge
ratio of ions is determined by the distance each ion travels during a fixed time period; the mass spectrum is then recorded
with a position-sensitive detector. The DOF approach provides a new way to separate and quantify components of complex samples.
Initial results are demonstrated with a glow discharge ion source and a microchannel plate–phosphor screen detector assembly
for atomic ion determination. This detection system demonstrated mass spectral peak widths of approximately 0.65 mm, corresponding
to resolving powers of approximately 400–600 for a number of elemental samples. 相似文献
3.
A simple fluorescent probe, which contains rhodamine and aminoquinoline moieties, was designed and prepared for selective detection of Hg2+ in acetonitrile. RbQ exhibited high selectivity and sensitivity toward Hg2+ over other common metal ions. The recognition of RbQ toward Hg2+ can be detected by fluorescence spectra, absorption spectra, and even by naked eyes. The binding ratio of the RbQ–Hg2+ complex was found to be 1:1 according to Job plot experiment, and the limit of detection was 1.05×10−7 M. Moreover, the prepared complex RbQ–Zn2+ (RbQZ) could detect Hg2+ in a ratiometric way and showed lower limit of detection (2.95×10−8 M) than RbQ in the same condition. Finally, we also demonstrated that the aminoquinoline–zinc complex could be served as a new and effective FRET donor for rhodamine derivatives. 相似文献
4.
Vibrational spectroscopy standoff detection of explosives 总被引:1,自引:0,他引:1
Leonardo C. Pacheco-Londoño William Ortiz-Rivera Oliva M. Primera-Pedrozo Samuel P. Hernández-Rivera 《Analytical and bioanalytical chemistry》2009,395(2):323-335
Standoff infrared and Raman spectroscopy (SIRS and SRS) detection systems were designed from commercial instrumentation and
successfully tested in remote detection of high explosives (HE). The SIRS system was configured by coupling a Fourier-transform
infrared interferometer to a gold mirror and detector. The SRS instrument was built by fiber coupling a spectrograph to a
reflective telescope. HE samples were detected on stainless steel surfaces as thin films (2–30 μg/cm2) for SIRS experiments and as particles (3–85 mg) for SRS measurements. Nitroaromatic HEs: TNT, DNT, RDX, C4, and Semtex-H
and TATP cyclic peroxide homemade explosive were used as targets. For the SIRS experiments, samples were placed at increasing
distances and an infrared beam was reflected from the stainless steel surfaces coated with the target chemicals at an angle
of ∼180° from surface normal. Stainless steel plates containing TNT and RDX were first characterized for coverage distribution
and surface concentration by reflection–absorption infrared spectroscopy. Targets were then placed at the standoff distance
and SIRS spectra were collected in active reflectance mode. Limits of detection (LOD) were determined for all distances measured
for the target HE. LOD values of 18 and 20 μg/cm2 were obtained for TNT and RDX, respectively, for the SIR longest standoff distance measured. For SRS experiments, as low
as 3 mg of TNT and RDX were detected at 7 m source–target distance employing 488 and 514.5 nm excitation wavelengths. The
first detection and quantification study of the important formulation C4 is reported. Detection limits as function of laser
powers and acquisition times and at a standoff distance of 7 m were obtained. 相似文献
5.
A mobile double-pulse laser-induced breakdown spectroscopy system for industrial environments is presented. Its capabilities
as a process analytical technique for the recovery of metals from molten inorganic wastes are investigated. Using low-melting
glass doped with different amounts of additives as a model system for recycling slags, the optimum number of shots, laser
inter-pulse and acquisition delay times are optimized for solid and liquid (1200 °C) glass. Limits of detection from 7 ppm
(Mn) to 194 ppm (Zn) are achieved working at a distance of 75 cm from the sample. To simplify the quantification of molten
samples in an industrial furnace, the possibility is examined of using solid standards for analysis of molten material. 相似文献
6.
《Arabian Journal of Chemistry》2020,13(4):5075-5083
In this work, green fluorescent carbon dots with a high relative quantum yield of 74.13% were synthesized by using one-pot hydrothermal hydrolysis of m-phenylenediamine (mPD) and PEG 1500 in H2SO4 solution at 180 °C for 10 h (mPD-CDs). In the presence of mPD-CDs, Fe2+ can form a complex with 1,10-phenanthroline (Fe(II) – phenanthroline) without interference from mPD-CDs, which has an absorption peak centered at 512 nm and its absorbance is sensitive to the concentration of Fe(II) – phenanthroline. Accordingly, a colorimetric method for the detection of Fe2+ was constructed with a limit of detection (LOD) of 2.98 μM. Moreover, the absorption spectrum of the Fe (II)-phenanthroline complex is overlapping with the excitation and emission spectra of mPD-CDs located at 440 and 516 nm, respectively, resulting in an inner filter effect (IFE) which is sensitive to the concentration of Fe(II) – phenanthroline. Correspondingly, a fluorimetric method for the detection of Fe2+ based on the mPD-CDs/phenanthroline system was built with a LOD as low as 0.59 μM. Therefore, colorimetric and fluorimetric dual mode detection of Fe2+ in aqueous solution can be achieved by a carbon dots/phenanthroline system. 相似文献
7.
《Arabian Journal of Chemistry》2023,16(4):104593
A multiplex polymerase chain reaction (PCR) detection method for the simultaneous detection of animal-derived components from deer, cow, sheep, pig and horse in edible meat was established, and a multiplex PCR detection kit for the rapid detection of animal-derived components was developed. According to the mitochondrial cytochrome b (Cyt b) gene of bovine species, sheep species, pig species and horse species and the mitochondrial cytochrome c oxidase subunit I (COX 1) gene of sika deer and red deer as the target gene sequences of primers, the specific primers of five different species were designed, the PCR system was optimized, and the multiplex PCR identification method of five animal-derived components was established. The minimum detection amount was determined by sensitivity test. The results showed that five meat specific amplification bands could be found at the same time in the same reaction system, including 173 bp fragment for venison, 148 bp for beef, 261 bp for pork, 100 bp for mutton and 424 bp for horse, indicating that the method is specific and stable. The minimum detection limit by this method was 1 ng/μL, showing a high sensitivity. According to the different sites in different areas of animal mitochondrial genes, a multiplex PCR detection method was established and a detection kit was developed, and the rapid, sensitive, stable and high-throughput detection of five animal-derived components and adulterated animal components in edible meat can be realized by using the kit. 相似文献
8.
As two members of the carbon materials family, carbon nanodots (CNDs) and graphene oxide (GO) possess many excellent optical properties resulting in a wide range of applications. In this work, the fluorescence of resultant dual-emission carbon nanodots (DECNDs) could be quenched by GO. In the presence of hemoglobin (Hb), the fluorescence would recover resulting from two interactions: one was the direct stacking effect of Hb on GO; the other one was that Hb could cover the surfaces of DECNDs; both of them would prevent the fluorescence quenching of DECNDs by GO. In the light of this mechanism, a novel fluorescent turn-off/on method has been developed for the detection of Hb based on DECNDs-GO system. By virtue of the dual emissions of these CNDs, it is noteworthy that both a single emission and ratiometric of dual emissions can be used to establish linear relationships of Hb: 0.05–300 nM (λem = 386 nm), 5–500 nM (λem = 530 nm), and 50–500 nM (I530/I410), with the corresponding limit of detection (LOD) as low as 20 pM, 2 nM and 20 nM, respectively. This present system is highly selective toward Hb over other proteins and this reliable method has been successfully applied for the detection of Hb in whole blood samples. 相似文献
9.
A simple,fast and low-cost turn-on fluorescence method for dopamine detection using in situ reaction
A simple, fast and low-cost method for dopamine (DA) detection based on turn-on fluorescence using resorcinol is developed. The rapid reaction between resorcinol and DA allows the detection to be performed within 5 min, and the reaction product (azamonardine) with high quantum yield generates strong fluorescence signal for sensitive optical detection. The detection exhibits a high sensitivity to DA with a wide linear range of 10 nM–20 μM and the limit of detection is estimated to be 1.8 nM (S/N = 3). This approach has been successfully applied to determine DA concentrations in human urine samples with satisfactory quantitative recovery of 97.84%–103.50%, which shows great potential in clinical diagnosis. 相似文献
10.
Measurements in complex matrices like milk still present a challenge in biosensor development. This is especially important
when using a label-free detection method or when measuring low analyte concentrations. The direct optical method reflectometric
interference spectroscopy (RIfS) was used for investigating matrix effects in immunoassay development. Furthermore, approaches
to reduce these effects have been established. As a model system, the hormone testosterone has been chosen because this immunoassay
has been well characterized in buffer. In a first step, the immunoassay for the detection of testosterone in buffer was improved
beyond former published results. Therefore, the sensor surface was optimized, resulting in a fivefold lower limit of detection
(70.2 ng L−1) and limit of quantification (130.0 ng L−1). Additionally, the assay time could be reduced to 15 min. Consequently, we used this improved assay to investigate matrix
effects of whole pasteurized bovine milk. To minimize these effects, the surface chemistry was adapted and a suitable evaluation
method was established, reducing the effects of Tyndall scattering and nonspecific binding to the sensor surface. These improvements
allow for very reliable quantitative measurements in milk. The assay developed required no sample pretreatment and allowed
for the regeneration of the sensor surface so that calibration could be performed on one chip. The calibration in milk (3.5%
fat) resulted in a limit of detection of 94.4 ng L−1 and a limit of quantification of 229.3 ng L−1. Furthermore, recovery rates between 70% and 120% could be obtained. Thus, for the first time, an analyte in the matrix milk
was successfully quantified with RIfS at low concentrations. 相似文献
11.
The method of pyridine temperature-programmed desorption (TPD) was applied for the measurement of acid properties of in situ reduced copper catalysts on silicate support. A thermal-conductivity detector (TCD) was used for the detection of TPD spectra of pyridine. The combination of flame-ionization detector and thermal conductivity detector shows that the region of TPD spectrum with the peak maxima TMAX1 = 350 °C is a superposition of the TCD response on spectra of desorbed pyridine, water and carbon dioxide, desorbing simultaneously from the catalyst surface. The method for the elimination of H2O and CO2 on the layer of NaOH was tested and the pure TPD spectrum of pyridine was obtained. The exact determination of pyridine concentration allows to estimate the amount of weak and medium acid centers of the catalyst. The gas chromatography with the mass spectroscopy (GC–MS) analyses was used for the interpretation of high temperature region of the pyridine TPD spectra (TMAX2 = 620 °C). It was found that pyridine bonded on the strong acid centers is decomposed to N2 and CO under very high temperature. The available chromatographic method for the separation of components present in pyridine TPD spectrum in the high-temperature region was suggested. The method for the quantification of strong acidity of copper-supported catalyst was found. 相似文献
12.
《Arabian Journal of Chemistry》2022,15(2):103569
Patulin (PAT) contamination in fruit and fruit products is a significant public health concern. Here, we developed a ratiometric fluorescent aptasensor for PAT detection based on aptamer-recognition and Exonuclease III amplification. Two structure selective dyes, SYBR Green I (SGI) and N-methyl mesoporphyrin IX (NMM), were used as fluorescent probes. In the developed biosensing system, the binding of PAT to aptamer triggered the liberation of cDNA. Subsequently, amplification was mediated by Exonuclease III. S1 was released from the S1-S2 duplex by enzymatic hydrolyzation and incorporated into a stable G-quadruplex. As a result, the fluorescence of SGI decreased, whereas that of NMM increased. There was a strong linear correlation between the relative fluorescence intensity and PAT concentrations (20 to 500 ng·L?1 range) (R2 = 0.99). The biosensing system was highly sensitive, and could detect PAT concentration as low as 4.7 ng·L?1. The sensor was also highly specific, and could differentiate PAT from several other related mycotoxins. In summary, we developed a new bioassay for the accurate detection of PAT contamination in fruits and fruit products. This research provides a new approach for developing ratiometric bioassays based on structure-selective dyes and enzymatic conversion processes. 相似文献
13.
A protein array chip for label-free optical detection of low molecular weight compounds has been developed. As a proof of
principle, the chip is proven capable of rapidly (approximately 1 min) determining hits from aqueous cocktails composed of
four common narcotics, cocaine, ecstasy, heroin, and amphetamine, using imaging surface plasmon resonance (SPR) as the detection
principle. The chip is produced by injecting a mixture of antibodies and letting them self-sort and bind to narcotic analog
coupled proteins already present in a predefined pattern on the supporting substrate. An indirect detection method, where
antibodies are displaced from the surface upon recognition of their corresponding narcotics, is used to obtain the optical
contrast and thus a detectable SPR and/or ellipsometric signal. Two types of readouts are possible from the present setup:
intensity SPR images and SPR/ellipsometric sensorgrams. Positive hits were routinely obtained for analyte concentrations of
50 pg/μL and the limit of detection, without any parameter optimizations, seems to fall in the range 0.5 pg/μL (1.4 nM) for
heroin, 2.5 pg/μL (8.2 nM) for cocaine, and 5 pg/μL for the other two narcotics (26 nM for ecstasy and 37 nM for amphetamine).
With improved readout possibilities (sampling frequency), signal evaluation algorithms, and antibody–antigen design strategies,
we believe this limit can be further improved. The chip is shown to work for many measurement cycles with excellent reproducibility.
Moreover, with a more advanced fluidic system, excess injected antibodies could be collected and reused for many cycles, which
could make the running costs of the system very low. The chip is in no way limited to detection of narcotics. Other low molecular
weight compounds could easily be detected on the same chip. For example, trinitrotoluene detection has already been demonstrated
using our chip. Possible areas of application for the system are therefore envisaged in airport and underground transport
security, customs, drug interdiction, forensics, and as warning alerts on military equipment and personnel.
Figure Narcotics chip (left) composed of spots of piezodispensed analog-coupled proteins that are loaded with antibodies to form
a patterned regions represented by the capital letter of the four different narcotics in focus. (Right) The same chip showing
hits for ectasy and herion in the cocktail. Both images are obtained in imaging surface plasmon resonance mode 相似文献
14.
Kishikawa N Ohkubo N Ohyama K Nakashima K Kuroda N 《Analytical and bioanalytical chemistry》2011,400(2):381-385
Ubiquinone is an important biologically active compound in the living body. The determination of ubiquinone in human plasma
is useful for the investigation of bioavailability of ubiquinone and for early diagnosis of several diseases. Therefore, we
developed a high-performance liquid chromatography (HPLC) with chemiluminescence detection method for the analysis of ubiquinone
in plasma samples. The method is based on luminol chemiluminescence detection of super oxide anion that is generated by the
redox cycle reaction between ubiquinone and dithiothreitol. The HPLC system involved an octyl column with a mobile phase of
methanol. Ubiquinone eluted from the column was mixed with dithiothreitol and luminol solutions simultaneously, and generated
chemiluminescence was monitored by chemiluminescence detector. The calibration curve for standard ubiquinone solution was
linear from 0.09 to 43.2 μg/mL (0.45–216 ng on column) with the correlation coefficient of 0.999, and the detection limit
(S/N = 3) was 26 ng/mL (130 pg on column). Using the proposed HPLC method, the peak of ubiquinone in human plasma could be
clearly detected on the chromatogram without any interference from plasma components. 相似文献
15.
《Arabian Journal of Chemistry》2022,15(9):104067
Sulfadiazine (SDZ) is a broad-spectrum antibiotic used to treat bacterial infections in animals, and SDZ residues in food can be harmful to human health. As a result, an aptasensor based on silica nanoparticles was developed for the rapid detection of SDZ. An aptamer that specifically binds to SDZ was obtained using graphene oxide-SELEX and further truncated to a 13 nt sequence (SDZ30-1:5′-AACCCAATGGGAT-3′), which has a high affinity (Kd = 65.72 nM). In addition, it was found by molecular simulation that a steric hindrance could prevent the target molecule from entering the binding pocket formed by the key base “TGG”, which affects the total binding free energy of SDZ30-1 and the target molecule, thereby affecting the affinity of SDZ30-1 to the target. The SDZ30-1 was selected as the fluorescent probe to establish an aptasensor for the detection of SDZ residues in milk and honey. The aptasensor exhibited a wide dynamic linear range (3.125 – 100 ng/mL) and a limit of detection (LOD = 1.68 ng/mL). The aptasensor in spiked samples recovered at a rate of 95.12 – 105.47%, with a coefficient of variation of less than 13.18 %. The results of aptasensor were positively correlated with those of HPLC (R2 > 0.8687). Based on the above results, it could be inferred that the aptasensor can be used sensitively and rapidly for the detection of SDZ residues in edible tissue. 相似文献
16.
Tsung-Ting Shih Cheng-Chuan HsiehYu-Ting Luo Yi-An SuPing-Hung Chen Yu-Chen ChuangYuh-Chang Sun 《Analytica chimica acta》2016
Herein, a hyphenated system combining a high-throughput solid-phase extraction (htSPE) microchip with inductively coupled plasma-mass spectrometry (ICP-MS) for rapid determination of trace heavy metals was developed. Rather than performing multiple analyses in parallel for the enhancement of analytical throughput, we improved the processing speed for individual samples by increasing the operation flow rate during SPE procedures. To this end, an innovative device combining a micromixer and a multi-channeled extraction unit was designed. Furthermore, a programmable valve manifold was used to interface the developed microchip and ICP-MS instrumentation in order to fully automate the system, leading to a dramatic reduction in operation time and human error. Under the optimized operation conditions for the established system, detection limits of 1.64–42.54 ng L−1 for the analyte ions were achieved. Validation procedures demonstrated that the developed method could be satisfactorily applied to the determination of trace heavy metals in natural water. Each analysis could be readily accomplished within just 186 s using the established system. This represents, to the best of our knowledge, an unprecedented speed for the analysis of trace heavy metal ions. 相似文献
17.
Tissue equivalent radiochromic gel material containing ferrous ions, xylenol-orange ion indicator and gelatin as gelling agent (FXG) is known to be sensitive to γ- and X-rays; hence it has been used for ionizing radiation dosimetry. Changes in optical absorbance properties of FXG material over a wide region in the visible spectrum were found to be proportional to the radiation absorbed dose. An earlier study demonstrated the sensitivity of FXG gel detector to ultraviolet radiation and therefore that could give quantitative measure for UV exposure. This study focuses on the detection of UVA radiation (315–400 nm), which forms an important part (~97%) of the natural solar UV radiation reaching the earth surface. A solar UV simulator device was used to deliver UVA radiation to FXG samples. The beam was optically modified to irradiate gel samples at an exposure level about 58 W/m2, which is comparable to the summer natural UVA radiation measured outside the laboratory building at midday (~60 W/m2). Experimental results were used to generate mathematical second order formulas that give the relationship between UVA dose and optical absorbance changes observed at two wavelengths in the visible region of the spectrum—430 and 560 nm. 相似文献
18.
《Arabian Journal of Chemistry》2023,16(3):104520
A novel nanoprobe based on S,O-doped carbon nitride quantum dots (S,O-CNQDs) was designed and synthesized. The as-prepared S,O-CNQDs exhibits good biocompatibility and strong fluorescence at excitation 360 nm. It is found that folic acid (FA) could efficiently quench the fluorescence of S,O-CNQDs. The obtained S,O-CNQDs is capable of acting as a sensitive and selective probe for FA detection in the range 5.0–83.3 μM with a detection limit of 90 nM. The as-prepared probe has been successfully utilized for the detection of FA in various real samples with satisfactory recoveries (98.8–107 %) and small relative standard deviation (<5%). The reaction mechanism between S,O-CNQDs and FA has been discussed. In addition, FA-S,O-CNQDs formed through a classical cross-linking reaction between FA and S,O-CNQDs easily accesses and penetrates into HepG2 cells with high folate receptors expression. FA-S,O-CNQDs with low cytotoxicity and good biocompatibility shows great potential in FA detection and targeted imaging of cancer cells. 相似文献
19.
《Arabian Journal of Chemistry》2023,16(4):104582
Viral hepatitis is a common infectious disease caused by five viruses (hepatitis virus A, B, C, D, and E). Given the diversity of hepatitis virus, rapid screening and accurate typing of viral hepatitis are the prerequisites for hepatitis therapy. Here, a multicolor fluorescence system was constructed by combining with the multi-color fluorescence properties of CdSe/ZnS quantum dots (QDs, emission wavelengths: 525 nm, 585 nm and 632 nm) and the broad-spectrum fluorescence quenching performance of GO. Taking advantage of the specific recognition of ssDNA modified CdSe/ZnS QDs to target hepatitis virus DNA, the constructed system could effectively distinguish hepatitis A virus DNA (HAV-DNA), hepatitis B virus DNA (HBV-DNA), and hepatitis C virus DNA (HCV-DNA) in a homogeneous solution. Based on the different adsorption property of GO for ssDNA and dsDNA, the fluorescence Forster resonance energy transfer (FRET) process between ssDNA modified QDs and GO could be regulated. The fluorescence signal of the constructed system presented a sensitive response to HAV-DNA, HBV-DNA, and HCV-DNA content in the range of 1.0–192 nM, 8.0–192 nM, and 1.0–128 nM, respectively. The limit of detection for HAV-DNA, HBV-DNA, and HCV-DNA is 0.46 nM, 1.53 nM, and 0.58 nM. The constructed system can be used to screen hepatitis virus DNA in real samples, which provides an alternative strategy for rapid screening and diagnosis of viral hepatitis. 相似文献
20.
Binyuan Xia Mingfu Chu Shaofei Wang Wanqing Wang Shanli Yang Chengbin Liu Shenglian Luo 《Analytica chimica acta》2015
Here for the first time, we present a novel electrochemiluminescence (ECL) sensor based on graphitic carbon nitride/graphene oxide (g-C3N4/GO) hybrid for the ultrasensitive detection of Cu2+, which is a common pollutant in environmental system. The g-C3N4/GO shows stable ECL signal in the presence of the self-produced coreactant from oxygen reduction, and the ECL signal could be effectively quenched by Cu2+, the possible ECL detection mechanism has been proposed in detail. GO can not only significantly enhance the cathodic ECL signal of g-C3N4 (∼3.8 times), but also serve as immobilization platform for g-C3N4. After optimization of experimental conditions, the proposed protocol can offer an ultrasensitive, highly selective and recyclable method for the detection of Cu2+ with a low detection limit of 1.0 × 10−11 M and a wide linear range from 1.0 × 10−11 to 1.0 × 10−7 M. Moreover, the practicability of the ECL sensor in real wastewater samples is also tested, showing that the proposed ECL sensor could be a promising alternative method for the emergency and routine monitoring of Cu2+ in real sample. 相似文献