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1.
A novel method for the determination of proteins at nanogram levels was proposed based on the decrease of resonance light
scattering (RLS) signal resulting from the interaction of dibromo-o-nitrophenylfluorone (DBONPF)-sodium lauroyl glutamate
(SLG) with proteins. At pH 2.97, the decrease RLS intensity was proportional to the concentration of proteins in the range
of nanogram levels with 3σ detection limits being 3.4 ng mL−1 for bovine serum albumin (BSA), 1.7 ng mL−1 for human serum albumin (HSA), 4.1 ng mL−1 for γ-globulin (γ-IgG), 4.4 ng mL−1 for egg albumin, 6.2 ng mL−1 for pepsin (Pep) and 3.7 ng mL−1 for α-chymotrypsin (Chy). The method is no protein-to-protein variability, simple, rapid, practical and relatively free
from interference from coexisting substance, as well as much more sensitive than most of the reported methods. The proposed
method was successfully applied to determine total protein in human serum samples. 相似文献
2.
Akhmad Sabarudin Osamu Noguchi Mitsuko Oshima Keiro Higuchi Shoji Motomizu 《Mikrochimica acta》2007,159(3-4):341-348
Chitosan resin functionalized with 3,4-dihydroxy benzoic acid (CCTS-DHBA resin) was used as a packing material for flow injection
(FI) on-line mini-column preconcentration in combination with inductively coupled plasma-atomic emission spectrometry (ICP-AES)
for the determination of trace elements such as silver, bismuth, copper, gallium, indium, molybdenum, nickel, uranium, and
vanadium in environmental waters. A 5-mL aliquot of sample (pH 5.5) was introduced to the minicolumn for the adsorption/preconcentration
of the metal ions, and the collected analytes on the mini-column were eluted with 2 M HNO3, and the eluates was subsequently transported via direct injection to the nebulizer of ICP-AES for quantification. The parameters
affecting on the sensitivity, such as sample pH, sample flow rate, eluent concentration, and eluent flow rate, were carefully
examined. Alkali and alkaline earth metal ions commonly existing in river water and seawater did not affect the analysis of
metals. Under the optimum conditions, the method allowed the determination of metal ions with detection limits of 0.08 ng mL−1 (Ag), 0.9 ng mL−1 (Bi), 0.07 ng mL−1 (Cu), 0.9 ng mL−1 (Ga), 0.9 ng mL−1 (In), 0.08 ng mL−1 (Mo), 0.09 ng mL−1 (Ni), 0.9 ng mL−1 (U), and 0.08 ng mL−1 (V). By using 5 mL of sample solution, the enrichment factor and collection efficiency were 8–12 fold and 96–102%, respectively,
whereas the sample throughput was 7 samples/hour. The method was validated by determining metal ions in certified reference
material of river water (SLRS-4) and nearshore seawater (CASS-4), and its applicability was further demonstrated to river
water and seawater samples. 相似文献
3.
A new chemiluminescence (CL) method combined with flow injection technique is described for the determination of Cr(III) and
total Cr. It is found that a strong CL signal is generated from the reaction of Cr(III), lucigenin and KIO4 in alkaline condition. The determination of total Cr is performed by pre-reduction of Cr(VI) to Cr(III) by using H2SO3. The CL intensity is linearly related to the concentration of Cr in the range 4.0 × 10−10–1.0 × 10−6 g mL−1. The detection limit (3s
b) is 1 × 10−10 g mL−1 Cr and the relative standard deviation is 1.9% (5.0 × 10−8 g mL−1 of Cr(III) solution, n = 11). The method was applied to the determination of Cr(III) and total Cr in water samples and compared satisfactorily with
the official method. 相似文献
4.
Ning Zhang Qing-Cheng Kong Zhen-Zhen Chen Ke-Hua Xu Bo Tang 《Mikrochimica acta》2007,158(1-2):165-171
A sensitive catalytic kinetic spectrofluorimetric approach for determining ng mL−1 levels of rhodium is presented, and the possible mechanism of the catalytic reaction was investigated. The determination
is based on the catalytic property of rhodium to enhance the reaction of o-vanillin salicylhydrazone (OVSH) with potassium
bromate in a water-ethanol medium at pH 4.80 and 45 °C. The presence of β-cyclodextrin (β-CD) obviously sensitized the assay
due to its high inclusion ability towards OVSH. Under optimized experimental conditions, fluorescence measurements of the
β-CD-rhodium-KBrO3-OVSH catalytic kinetic reaction system were carried out in its fluorescent band centered at λex = 333 nm and λem = 476 nm, respectively. The calibration graph was linear over the concentration range of 0.47–100 ng mL−1 with a detection limit of 0.14 ng mL−1. The effect of interferences was discussed, and the results show that the extraction method can be used to separate rhodium
from interference species such as iridium. The proposed method, applied to several synthetic mixtures containing rhodium mixed
with varying amounts of metal salts, produced satisfactory results. 相似文献
5.
A new method of direct single-drop microextraction combined with electrothermal atomic absorption spectrometry (ETAAS) is
presented for the determination of trace Cd and Pb with dithizone (H2DZ) as chelating reagent. Factors influencing the microextraction efficiency and determination, such as pH, microdrop volume,
stirring rate, extraction time were evaluated. Under the optimized experimental conditions, the detection limits of the method
are 2 and 90 pg mL−1 for Cd and Pb, and the relative standards deviations for 0.5 ng mL−1 Cd and 10 ng mL−1 Pb are 11 and 12.8%. After 10 min of extraction, the enrichment factors for Cd and Pb are 118 and 90, respectively. The results
for the determination of Cd and Pb in tap water, spring water, river water, pond water, lake water and spiked water samples
demonstrate the accuracy, recovery and applicability of the method. An environmental water certified reference material (GSBZ
50009-88) was analyzed, and the determined values are in a good agreement with the certified values.
Correspondence: Bin Hu, Department of Chemistry, Wuhan University, Wuhan 430072, P.R. China 相似文献
6.
Development of a cloud point extraction and preconcentration method for silver prior to flame atomic absorption spectrometry 总被引:1,自引:0,他引:1
The possibility was investigated of using 2-mercaptobenzothiazole (MBT) for Ag(I) concentration by micellar extraction at
cloud point (CP) temperature and subsequent determination by flame atomic absorption spectrometry (FAAS). The method is based
on the complexation of Ag(I) with 2-mercaptobenzothiazole (MBT) in the presence of non-ionic micelles of Triton X-114. The
effect of experimental conditions such as pH, concentration of chelating agent and surfactant, equilibration temperature and
time on cloud point extraction was studied. Under the optimum conditions, the preconcentration of 10 mL of water sample in
the presence of 0.1% Triton X-114 and 2 × 10−4 mol L−1 2-mercaptobenzothiazole permitted the detection of 2.2 ng mL−1 silver. The calibration graph was linear in the range of 10–200 ng mL−1, and the recovery of more than 99% was achieved. The proposed method was used in FAAS determination of Ag(I) in water samples. 相似文献
7.
A simple flow injection chemiluminescence (CL) method was developed for the determination of atenolol using Eu3+ as the probe. It was found that the weak CL generated by the KMnO4-Na2SO3 reaction can be significantly enhanced by the atenolol-Eu3+ complex. The experimental conditions were optimized. The CL intensity was linearly related to atenolol concentration in the
range from 8.0 × 10−9 to 1.0 × 10−5 g mL−1. The detection limit (3s
b) was 3 × 10−9 g mL−1 and the relative standard deviation for 1.0 × 10−7 g mL−1 atenolol solution was 2.4% (n = 11). The method has high sensitivity, wide linear range, inexpensive instrumentation, and has been applied to the determination
of atenolol in spiked human urine and plasma samples with recoveries within the range 95.5–104.0%.
Supplementary material to this paper is available in electronic form at
Electronic supplementary material: Discussion of the reaction mechanism and additional figures are available online as electronic
supplementary material (ESM) at .
Correspondence: Jianxiu Du, Key Laboratory of Analytical Chemistry for Life Science of Shaanxi Province, School of Chemistry
and Materials Science, Shaanxi Normal University, Xi’an 710062, P.R. China 相似文献
8.
Ming-Zhou Zhang Min-Zi Wang Zong-Lun Chen Jie-Hong Fang Mei-Ming Fang Jun Liu Xiao-Ping Yu 《Analytical and bioanalytical chemistry》2009,395(8):2591-2599
A multianalyte lateral-flow immunochromatographic technique using colloidal gold-labeled polyclonal antibodies was developed
for the rapid simultaneous detection of clenbuterol and ractopamine. The assay procedure could be accomplished within 5 min,
and the results of this qualitative one-step assay were evaluated visually according to whether test lines appeared or not.
When applied to the swine urines, the detection limit and the half maximal inhibitory concentration (IC50) of the test strip under an optical density scanner were calculated to be 0.1 ± 0.01 ng mL−1 and 0.1 ± 0.01 ng mL−1, 0.56 ± 0.08 ng mL−1, and 0.71 ± 0.06 ng mL−1, respectively, the cut-off levels with the naked eye of 1 ng mL−1 and 1 ng mL−1 for clenbuterol and ractopamine were observed. Parallel analysis of swine urine samples with clenbuterol and ractopamine
showed comparable results obtained from the multianalyte lateral-flow test strip and GC-MS. Therefore, the described multianalyte
lateral-flow test strip can be used as a reliable, rapid, and cost-effective on-site screening technique for the simultaneous
determination of clenbuterol and ractopamine residues in swine urine.
相似文献
9.
Jibrin Sabo Suleiman Bin Hu Xuli Pu Chaozhang Huang Zucheng Jiang 《Mikrochimica acta》2007,159(3-4):379-385
A new method is proposed using a microcolumn (20 mm × 2.0 mm) packed with nanometer-sized zirconia as solid-phase extractor
for the separation/preconcentration of Mn, Cu, Cr, Zn, Ni and Co prior to their determination by inductively coupled plasma
optical emission spectrometer (ICP-OES) in environmental samples. The factors affecting the separation and preconcentration
of analytes such as pH, sample flow rate and volume, eluent concentration and volume were determined, interfering ions were
studied, and the optimal experimental conditions were established. The adsorption capacity of nanometer-sized ZrO2 for Mn, Cu, Cr, Zn, Ni and Co was found to be 1.3, 1.3, 1.7, 2.0, 3.9 and 1.5 mg g−1, respectively. The detection limits of the method were 12, 58, 24, 2, 7 and 36 ng L−1, respectively, with a preconcentration factor of 25. The precision of this method was 1.7% (Mn), 2.9% (Cu), 5.9% (Mn), 3.8%
(Mn), 6.2% (Mn) and 4.3% (Mn) with 9 determinations of 10 ng mL−1 of target analytes, respectively. The method was successfully applied to the determination of trace metals in lake water,
dried fish samples, certified reference materials of human hair and milk, and provided satisfactory results. 相似文献
10.
A novel molecularly imprinted polymer solid-phase extraction (MISPE) with flow-injection chemiluminescence (CL) was developed
for the determination of pazufloxacin mesilate (PZFX). The molecularly imprinted polymer (MIP) was synthesized by using PZFX
as the imprinting molecule. A glass tube packed the particles of the MIP was employed as MISPE micro-column, which was connected
into the sampling loop of the eight-way injection valve for on-line selective preconcentration and extraction of PZFX. The
eluent of acetonitrile:acetic acid (9:1, v:v) was used as carrier for eluting the adsorbed PZFX to react with the mixture
of cerium(IV) and sodium sulfite in the flow cell to produce strong CL. The relative intensity of CL was linear to PZFX concentration
in the range from 2.5 × 10−9 to 2.5 × 10−7 g mL−1. The limit of detection was 7 × 10−10 g mL−1 (3 σ) and the relative standard deviation for 5 × 10−8 g mL−1of PZFX solution was 3.7% (n = 7). This method has been applied to the determination of PZFX in human urine. 相似文献
11.
A fast and sensitive liquid chromatography–mass spectrometry method was developed for the determination of ursolic acid (UA)
in rat plasma and tissues. Glycyrrhetinic acid was used as the internal standard (IS). Chromatographic separation was performed
on a 3.5 μm Zorbax SB-C18 column (30 mm × 2.1 mm) with a mobile phase consisting of methanol and aqueous 10 mM ammonium acetate
using gradient elution. Quantification was performed by selected ion monitoring with (m/z)− 455 for UA and (m/z)− 469 for the IS. The method was validated in the concentration range of 2.5 − 1470 ng mL−1 for plasma samples and 20 − 11760 ng g−1 for tissue homogenates. The intra- and inter-day assay of precision in plasma and tissues ranged from 1.6% to 7.1% and 3.7%
to 9.0%, respectively, and the intra- and inter-day assay accuracy was 84.2 − 106.9% and 82.1 − 108.1%, respectively. Recoveries
in plasma and tissues ranged from 83.2% to 106.2%. The limits of detections were 0.5 ng mL−1 or 4.0 ng g−1. The recoveries for all samples were >90%, except for liver, which indicated that ursolic acid may metabolize in liver. The
main pharmacokinetic parameters obtained were T
max = 0.42 ± 0.11 h, C
max = 1.10 ± 0.31 μg mL−1, AUC = 1.45 ± 0.21 μg h mL−1 and K
a = 5.64 ± 1.89 h−1. The concentrations of UA in rat lung, spleen, liver, heart, and cerebellum were studied for the first time. This method
is validated and could be applicable to the investigation of the pharmacokinetics and tissue distribution of UA in rats. 相似文献
12.
Andreas Rahm Evgeni M. Kaidashev Heidemarie Schmidt Mariana Diaconu Andreas Pöppl Rolf Böttcher Christoph Meinecke Tilman Butz Michael Lorenz Marius Grundmann 《Mikrochimica acta》2006,153(1-2):21-25
A flow injection chemiluminescence method is proposed for the determination of cobalt, based on the strong catalytic effect
of Cobalt(II) (1,10-phenanthroline)3 complex on the lucigenin-periodate reaction in alkaline medium. Under the optimum experimental conditions, the chemiluminescence
signal responded linearly to the concentration of cobalt(II) in the 1.0 × 10−9–3.0 × 10−7 g mL−1 range with a detection limit of 4.4 × 10−10 g mL−1 cobalt(II). The relative standard deviation for the determination of 5.0 × 10−8 g mL−1 of cobalt was 2.3% in eleven replicated measurements. The method was successfully applied to the determination of cobalt(II)
in pharmaceutical preparations. 相似文献
13.
CdTe quantum dots (QDs) were modified with thioglycolic acid (TGA) and synthesized in aqueous medium. The optimum fluorescence
intensity was found to be at pH 6.24 with a CdTe QDs concentration of 4.96 × 10−7 mol L−1. The quenched fluorescence intensity of CdTe QDs is linearly proportional to V(V) concentration from 10 to 200 ng mL−1 with correlation coefficient R = 0.9985. The limit of detection for V(V) was 2.07 ng mL−1. The proposed method was successfully applied to the analysis of trace amounts of V(V) in water samples with recovery of
96.5–101.8%, and the results were in good agreement with those of electrothermal atomic absorption spectrometry. 相似文献
14.
A sensitive chemiluminescence method for the determination of clindamycin is presented. The method is based on the inhibitory
effect of clindamycin on the chemiluminescence reaction between luminol and myoglobin in a flow-injection system. The decrement
in chemiluminescence intensity is linear with the logarithm of the clindamycin concentration over the range of 0.1–70.0 ng mL−1 (r
2 = 0.9995), with a detection limit of 0.03 ng mL−1 (3σ). At a flow rate of 2.0 mL min−1, the complete analytical process could be performed within 0.5 min, including sampling and washing, with a relative standard
deviation of less than 3.0% (n = 5). The procedure was applied to the determination of clindamycin in human serum and in monitoring
the excretion of clindamycin in human urine samples without any pretreatment process. It was found that the excretive clindamycin
concentration reached its maximum 3 hours after oral administration. The clindamycin excretive ratio in 9 hours was 10.84%
in the body of the volunteer. 相似文献
15.
Chunyan Yang Zhujun Zhang Jinli Wang 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2010,75(1):77-82
A novel flow-injection chemiluminescence (CL) method for the determination of dihydralazine sulfate (DHZS) is described. The method is based on the reaction of luminol and diperiodatocuprate (K2[Cu(H2IO6)(OH)2], DPC) in alkaline medium to emit CL, which is greatly enhanced by DHZS. The possible CL mechanism was first proposed based on the kinetic characteristic, CL spectrum and UV spectra. The optimum condition for the CL reaction was in detail studied using flow-injection system. The experiments indicated that under optimum condition, the CL intensity was linearly related to the concentration of DHZS in the range of 7.0 × 10?9 to 8.6 × 10?7 g mL?1 with a detection limit (3σ) of 2.1 × 10?9 g mL?1. The proposed method had good reproducibility with the relative standard deviation 3.1% (n = 7) for 5.2 × 10?8 g mL?1 of DHZS. This method has the advantages of simple operation, fast response and high sensitivity. The special advantage of the system is that very low concentration of luminol can react with DPC catalyzed by DHZS to get excellent experiment results. And CL cannot be observed nearly when luminol with same concentration reacts with other oxidants, so luminol–DPC system has higher selectivity than other luminol CL systems. The method has been successfully applied to determine DHZS in serum. 相似文献
16.
Simple and rapid fluorometric screening methods have been developed based on the competitive binding between the target and
an intercalating fluorophore dye to double-stranded-DNA (dsDNA). In this study, the long-wavelength fluorescente dye TOTO-3
was employed as the indicator. Compounds that interact with dsDNA will affect the binding of TOTO-3 to the nucleic acid thereby
changing the fluorescence intensity. The analyte concentration is indirectly determined by the decrease in fluorescence intensity.
A fiber optic fluorescence screening system was developed for rapid and convenient sample processing. Lambda DNA (48.5 kb)
was chosen as a suitable sensing nucleic acid material. Detection of sulfathiazole and chloramphenicol in shrimps using this
method was studied in the range of 0.5–25 ng mL−1 of sulfathiazole and of 1–50 ng mL−1 of chloramphenicol. Detection limits of 0.5 ng mL−1 of sulfathiazole and 1 ng mL−1 of chloramphenicol were achieved. This approach is useful as a routine test in the monitoring of antibiotics in the environment
or aquaculture products. The easy operation and the rapid and sensitive detection make this a potential high-throughput screening
method. 相似文献
17.
A simple and selective method using ammonium pyrrolidinedithiocarbamate modified activated carbon (APDC-AC) as solid phase
extractant has been developed for speciation of As(III) in water samples. At pH 1.8–3.0, As(III) could be adsorbed quantitatively
by APDC-AC, and then eluted completely with 2.0 mL of 0.1 mol L−1 HNO3, while As(V) could almost not be retained at pH 1–7. Effects of acidity, sample flow rate, concentration of elution solution
and interfering ions on the recovery of As(III) have been systematically investigated. Under the optimal conditions, the adsorption
capacity of APDC-AC for As(III) is 7.3 mg g−1. The detection limit (3σ) of As(III) is 0.05 ng mL−1 for graphite furnace atomic absorption spectrometry (GFAAS) with enrichment factor of 50, and the relative standard deviation
(RSD) is 4.1% (n = 9, C = 5 ng mL−1). The method has been applied to the determination of trace As(III) in water, and the recoveries of As(III) are 100 ± 10%.
Correspondence: Yiwei Wu, Department of Chemistry and Environmental Engineering, Hubei Normal University, Huangshi 435002,
P.R. China 相似文献
18.
A green, simple, non-toxic, and sensitive sample pretreatment procedure coupled with high-performance liquid chromatography
(HPLC) was developed for the analysis of chloramphenicol (CAP) that exploits an aqueous two-phase system based on imidazolium
ionic liquid (1-butyl-3-methylimidazolium tetrafluoroborate, [Bmim]BF4) and organic salt (Na3C6H5O7) using a liquid–liquid extraction technique. The influence factors on partition behaviors of CAP were studied, including
the type and amount of salts, the pH value, the volume of [Bmim]BF4, and the extraction temperature. Extraction efficiency of the CAP was found to increase with increasing temperature and the
volume of [Bmim]BF4. Thermodynamic studies indicated that hydrophobic interactions were the main driving force, although electrostatic interactions
and salting-out effects were also important for the transfer of the CAP. Under the optimal conditions, 90.1% of the CAP could
be extracted into the ionic liquid-rich phase in a single-step extraction. This method was practical when applied to the analysis
of CAP in feed water, milk, and honey samples with a linear range of 2~1,000 ng mL−1. The method yielded a limit of detection of 0.3 ng mL−1 and a limit of quantification of 1.0 ng mL−1. The recovery of CAP was 90.4–102.7% from aqueous samples of real feed water, milk, and honey samples by the proposed method.
This novel process is much simpler and more environmentally friendly and is suggested to have important applications for the
separation of antibiotics. 相似文献
19.
Silica gel was prepared by the sol–gel method, modified with nanometer-sized zirconium oxide, and this material was characterized
by X-ray diffraction. A micro-column packed with silica gel modified with nanometer zirconium oxide as sorbent has been developed
for the quantitative separation and preconcentration of trace amounts of chromium(III) prior to their determination by electrothermal
atomic absorption spectrometry. Total chromium was determined after the reduction of chromium(VI) to chromium(III) by 10%
(m/v) of aqueous ascorbic acid as reducing reagent. The adsorption capacity for chromium(III) was found to be 2.36 mg g−1. The detection limit for chromium(III) was 15 ng L−1 with an enrichment factor of 100. The relative standard deviation was 3.2% (n = 7, c = 2.0 ng mL−1). 相似文献
20.
Viñas P López-García I Bravo-Bravo M Briceño M Hernández-Córdoba M 《Analytical and bioanalytical chemistry》2012,403(4):1059-1066
A miniaturized dispersive liquid–liquid microextraction (DLLME) procedure coupled to liquid chromatography (LC) with fluorimetric
detection was evaluated for the preconcentration and determination of thiamine (vitamin B1). Derivatization was carried out by chemical oxidation of thiamine with 5 × 10−5 M ferricyanide at pH 13 to form fluorescent thiochrome. For DLLME, 0.5 mL of acetonitrile (dispersing solvent) containing
90 μL of tetrachloroethane (extraction solvent) was rapidly injected into 10 mL of sample solution containing the derivatized
thiochrome and 24% (w/v) sodium chloride, thereby forming a cloudy solution. Phase separation was carried out by centrifugation, and a volume of
20 μL of the sedimented phase was submitted to LC. The mobile phase was a mixture of a 90% (v/v) 10 mM KH2PO4 (pH 7) solution and 10% (v/v) acetonitrile at 1 mL min−1. An amide-based stationary phase involving a ligand with amide groups and the endcapping of trimethylsilyl was used. Specificity,
linearity, precision, recovery, and sensitivity were satisfactory. Calibration graph was carried out by the standard additions
method and was linear between 1 and 10 ng mL−1. The detection limit was 0.09 ng mL−1. The selectivity of the method was judged from the absence of interfering peaks at the thiamine elution time for blank chromatograms
of unspiked samples. A relative standard deviation of 3.2% was obtained for a standard solution containing thiamine at 5 ng mL−1. The esters thiamine monophosphate and thiamine pyrophosphate can also be determined by submitting the sample to successive
acid and enzymatic treatments. The method was applied to the determination of thiamine in different foods such as beer, brewer’s
yeast, honey, and baby foods including infant formulas, fermented milk, cereals, and purees. For the analysis of solid samples,
a previous extraction step was applied based on an acid hydrolysis with trichloroacetic acid. The reliability of the procedure
was checked by analyzing a certified reference material, pig’s liver (CRM 487). The value obtained was 8.76 ± 0.2 μg g−1 thiamine, which is in excellent agreement with the certified value, 8.6 ± 1.1 μg g−1. 相似文献