共查询到20条相似文献,搜索用时 15 毫秒
1.
Baeten V von Holst C Garrido A Vancutsem J Michotte Renier A Dardenne P 《Analytical and bioanalytical chemistry》2005,382(1):149-157
In this paper we present an alternative method for detection of meat and bone meal (MBM) in feedstuffs by near-infrared microscopic (NIRM) analysis of the particles in the sediment fraction (dense fraction (d >1.62) from dichloroethylene) of compound feeds. To apply this method the particles of the sediment fraction are spread on a sample holder and presented to the NIR microscope. By using the pointer of the microscope the infrared beam is focussed on each particle and the NIR spectrum (1112–2500 nm) is collected. This method can be used to detect the presence of MBM at concentrations as low as 0.05% mass fraction. When results from the NIRM method were compared with the classical microscopic method, a coefficient of determination (R2) of 0.87 was obtained. The results of this study demonstrated that this method could be proposed as a complementary tool for the detection of banned MBM in feedstuffs by reinforcement of the monitoring of feeds. 相似文献
2.
Emilio Bustelo Isaac de los Ríos Manuel J. Tenorio M. Carmen Puerta Pedro Valerga 《Monatshefte für Chemie / Chemical Monthly》2000,131(12):1311-1320
Summary. The solid-state tautomerization of the hydrido-alkynyl derivatives [Cp
*RuH(C&*CR)-(dippe)][BPh4] (Cp* = C5Me5; R = SiMe3, Ph, H; dippe = 1,2-bis-(diisopropylphosphino)-ethane) to their vinylidene isomers [Cp
*Ru*C*CHR(dippe)][BPh4] was studied by IR spectroscopy. Characteristic isothermic αvs. t curves for each individual rearrangement process were recorded. Their shape, and hence the isomerization mechanism, depends
strongly on the nature of the substituent R. The kinetic analysis of the above curves using the Avrami-Erofeev provided some mechanistic information about the isomerization process in the solid.
Received July 7, 2000. Accepted August 29, 2000 相似文献
3.
Kamysek S Fuchs P Schwoebel H Roesner JP Kischkel S Wolter K Loeseken C Schubert JK Miekisch W 《Analytical and bioanalytical chemistry》2011,401(7):2093-2102
Breath analysis could offer a non-invasive means of intravenous drug monitoring if robust correlations between drug concentrations
in breath and blood can be established. In this study, propofol blood and breath concentrations were determined in an animal
model under varying physiological conditions. Propofol concentrations in breath were determined by means of two independently
calibrated analytical methods: continuous, real-time proton transfer reaction mass spectrometry (PTR-MS) and discontinuous
solid-phase micro-extraction coupled with gas chromatography mass spectrometry (SPME-GC-MS). Blood concentrations were determined
by means of SPME-GC-MS. Effects of changes in pulmonary blood flow resulting in a decreased cardiac output (CO) and effects
of dobutamine administration resulting in an increased CO on propofol breath concentrations and on the correlation between
propofol blood and breath concentrations were investigated in seven acutely instrumented pigs. Discontinuous propofol determination
in breath by means of alveolar sampling and SPME-GC-MS showed good agreement (R
2 = 0.959) with continuous alveolar real-time measurement by means of PTR-MS. In all investigated animals, increasing cardiac
output led to a deterioration of the relationship between breath and blood propofol concentrations (R
2 = 0.783 for gas chromatography-mass spectrometry and R
2 = 0.795 for PTR-MS). Decreasing pulmonary blood flow and cardiac output through banding of the pulmonary artery did not significantly
affect the relationship between propofol breath and blood concentrations (R
2 > 0.90). Estimation of propofol blood concentrations from exhaled alveolar concentrations seems possible by means of different
analytical methods even when cardiac output is decreased. Increases in cardiac output preclude prediction of blood propofol
concentration from exhaled concentrations. 相似文献
4.
Carbohydrazide is prepared by reacting dimethyl carbonate with hydrazine hydrate. Its single crystal has been cultured with slow evaporation method. Its molecular structure and crystal structure have been determined by X-ray single crystal diffraction technique. The obtained results shows that the crystal belongs to Crystal system of Monoclinic, space group P2(1)/n with crystal parameters of a = 3.725(1), b = 8.834(2), c = 11.96(3), β = 91.97(1)°, V = 392.23(2) 3, Z = 4, D
c = 1.522 g/cm3, μ = 0.128 mm−1, F0 0 0) = 192. Based on the crystal data, we have also carried quantum chemistry calculations on the title compound using the B3LYP and MP2 method with cc-pVTZ basis set. The calculation results further demonstrate the molecular structure of title compound and its coordination properties. 相似文献
5.
Neopterin is a valuable biomarker of cellular immunity associated with various pathological situations such as viral and bacterial
infections, autoimmune, cardiovascular, neurodegenerative and malignant disorders. To produce specific antibodies against
neopterin for a rapid multi-biomarker-based diagnosis, a novel hapten derivative was synthesized and attached to carrier proteins.
The thoroughly characterized conjugates were used for immunization of BALB/c mice and rabbits. The produced monoclonal antibody
reached in both direct and indirect enzyme-linked immunosorbent assay (ELISA) format LoD of 0.18 and 0.45 μg L−1, respectively, and was a superior immunoreagent for further biosensor developments with regard to assay sensitivity and material
availability. The best polyclonal antibody was somewhat more sensitive in direct ELISA with LoD of 0.05 μg L−1. The optimized ELISA method was evaluated with blood samples collected from patients with renal insufficiency, patients with
sepsis, patients without confirmed clinical diagnosis, and healthy volunteers. In plasma samples, neopterin concentrations
ranging from 3.2 to 103 μg L−1 could be determined with the monoclonal ELISA whereas twofold lower results were obtained with the polyclonal ELISA. A satisfactory
correlation of results was found between the polyclonal ELISA and IBL Neopterin ELISA kit within the concentration range 0.5–16 μg L−1 (R = 0.874; n = 40), and slightly lower correlation was found for monoclonal-based ELISA (R = 0.819; n = 40). These data show that the generated antibodies may be used as functional analytical reagents for the integration into
multianalyte biochip detection systems. 相似文献
6.
Ulrich Englich Ingo Prass Karin Ruhlandt-Senge Thorsten Schollmeier Frank Uhlig 《Monatshefte für Chemie / Chemical Monthly》2002,133(7):931-943
Summary. Hydrido substituted stannasilanes of the type or (Z = H, Me, Ph; R, R′ = alkyl, Ph) are accessible by reaction of either alkali metal stannides (MSn(Z)R
2; M = Li, Na) with halogen substituted silanes (; X = F, Cl) or chlorostannanes (R
2SnCl2, Ph3SnCl) and fluorosilanes in the presence of magnesium. Stannasilanes with halogen substituents at the silicon as well as the tin atom are formed by
treatment of the hydrido substituted stannasilanes with CHCl3 or CCl4. The hydrido substituted stannasilanes decompose in contact with air to distannanes and siloxanes or to the linear (
t
Bu2Sn(–O–
t
Bu2Si–OH)2) and cyclic ((–
t
Bu2Sn–O–
i
Pr2Si–O–)2) stannasiloxanes.
Received November 29, 2001. Accepted (revised) January 16, 2002 相似文献
7.
Lutz Preu Wolfgang Kliegel Steven J. Rettig James Trotter 《Monatshefte für Chemie / Chemical Monthly》2001,132(10):1213-1224
Summary. The structure of the dehydrogenation product 1′,3a′-dihydro-3′-((1,3-dioxoindan-2-ylidene)-phenyl-methyl)-5′-phenyl-spiro-(indan-2,1′-pyrrolo[3,4-c]pyrrole)-1,3,4′,6′-(5′H, 6a′H)-tetrone derived from the cycloadducts (±)-(3a′S,6a′R)-1′,3a′-dihydro-3′-((R)-α-(1,3-dioxoindanyl)-benzyl)-5′-phenyl-spiro-(indan-2,1′-pyrrolo[3,4-c]pyrrole)-1,3,4′,6′(5H,6a′H)-tetrone and/or (±)-(3a′S,6a′R)-1′,3a′-dihydro-3′-((S)-α-(1,3-dioxoindanyl)-benzyl)-5′-phenyl-spiro-(indan-2,1′-pyrrolo[3,4-c]pyrrole)-1,3,4′,6′(5H,6a′H)-tetrone, which were synthesized by 1,3-dipolar cycloaddition of N-phenylmaleimide to 2-((2-(1,3-dioxoindan-2-yl)-2-phenyl-ethenyl)-imino)-indan-1,3-dione,
was determined by X-ray analysis. Crystal data (CCD, 180 K): rhombohedral, R&3macr;;, a = 34.0871(7), c = 13.9358(5) ?, Z = 18; the structure was solved by direct methods and refined by full-matrix least-squares procedures to R(F, I ≥ 3σ(I)) = 0.053. The molecule contains a central folded ring system of two cis-fused 5-membered heterocyclic rings; each ring is nearly planar, and the angle between the rings amounts to 59.0°. Dynamic
1H NMR spectroscopy of the product revealed an exchange process caused by restricted rotation of the double bonded 1,3-indandione
moiety and the phenyl group about the Csp2-Csp2 single-bonds. Molecular modeling and complete lineshape analysis indicated a four site exchange process for which free energies
of activation and free energies could be established. ΔG
‡ values for the barriers of rotation are in the range of 57–59 kJ · mol − 1 at 273 K, which is unusually high for an unsubstituted phenyl group.
Received May 3, 2001. Accepted (revised) June 8, 2001 相似文献
8.
Mylonaki S Kiassos E Makris DP Kefalas P 《Analytical and bioanalytical chemistry》2008,392(5):977-985
An experimental setup based on a 23 full-factorial, central-composite design was implemented with the aim of optimising the recovery of polyphenols from olive
leaves by employing reusable and nontoxic solutions composed of water/ethanol/citric acid as extracting media. The factors
considered were (i) the pH of the medium, (ii) the extraction time and (iii) the ethanol concentration. The model obtained
produced a satisfactory fit to the data with regard to total polyphenol extraction (R
2 = 0.91, p = 0.0139), but not for the antiradical activity of the extracts (R
2 = 0.67, p = 0.3734). The second-order polynomial equation obtained after analysing the experimental data indicated that ethanol concentration
and time mostly affected the extraction yield, but that increased pH values were unfavourable in this regard. The maximum
theoretical yield was calculated to be 250.2 ± 76.8 mg gallic acid equivalent per g of dry, chlorophyll-free tissue under
optimal conditions (60% EtOH, pH 2 and 5 h). Liquid chromatography–electrospray ionisation mass spectrometry of the optimally
obtained extract revealed that the principal phytochemicals recovered were luteolin 7-O-glucoside, apigenin 7-O-rutinoside and oleuropein, accompanied by smaller amounts of luteolin 3′,7-O-diglucoside, quercetin 3-O-rutinoside (rutin), luteolin 7-O-rutinoside and luteolin 3′-O-glucoside. Simple linear regression analysis between the total polyphenol and antiradical activity values gave a low and
statistically insignificant correlation (R
2 = 0.273, p > 0.05), suggesting that it is not the sheer amount of polyphenols that provides high antioxidant potency; instead, this
potency is probably achieved through interactions among the various phenolic constituents. 相似文献
9.
Helvécio C. Menezes Leiliane C. A. Amorim Zenilda L. Cardeal 《Analytical and bioanalytical chemistry》2009,395(8):2583-2589
Benzene is classified as a Group I carcinogen by the International Agency for Research on Cancer (IARC). The risk assessment
for benzene can be performed by monitoring environmental and occupational air, as well as biological monitoring through biomarkers.
The present work developed and validated methods for benzene analysis by GC/MS using SPME as the sampling technique for ambient
air and breath. The results of the analysis of air in parks and avenues demonstrated a significant difference, with average
values of 4.05 and 18.26 μg m−3, respectively, for benzene. Sampling of air in the occupational environment furnished an average of 3.41 and 39.81 μg m−3. Moreover, the correlations between ambient air and expired air showed a significant tendency to linearity (R
2 = 0.850 and R
2 = 0.879). The results obtained for two groups of employees (31.91 and 72.62 μg m−3) presented the same trend as that from the analysis of environmental air. 相似文献
10.
A novel and reliable direct electrochemical method was established for the detection of adenine, based on the differential
pulse anodic stripping response at a poly(amidosulfonic acid) (poly-ASA)-modified glassy carbon electrode (GCE) fabricated
by electropolymerization. The characterization of electrochemically synthesized poly-ASA film was investigated by atomic force
microscopy, electrochemical impedance spectroscopy, and voltammetric methods. This poly-ASA-modified GCE could greatly enhance
the detection sensitivity of adenine. At optimum conditions, the anodic peak exhibits a good linear concentration dependence
in the range from 3.0 × 10−8 to 1.0 × 10−6 M (r = 0.9994). The detection limit is 8.0 × 10−9 M (S/N = 3). The proposed method could be used to determinate the adenine in tablets of vitamin B4 with satisfactory results. 相似文献
11.
Summary. Single crystals of sodium dithiophosphate undecahydrate (Na3PO2S2 · 11H2O) and sodium trithiophosphate undecahydrate (Na3POS3 · 11H2O) were grown from aqueous solution. The crystal structures of Na3PO2S2 · 11H2O (P212121; a = 1248.1(1), b = 945.2(1), c = 1383.1(1) pm; R
1 = 0.0202, wR
2 = 0.0502) and Na3POS3 · 11H2O (Pna21; a = 1262.0(2), b = 947.6(2), c = 1431.5(2) pm; R
1 = 0.0720, wR
2 = 0.1371) are related to each other in a sense that all constituting units are arranged in similar positions and with similar
orientations. The geometries of the anions were determined with high accuracy; thus, the structural parameters of the POS3−
3 anion were measured for the first time.
Received September 25, 2001. Accepted January 21, 2002 相似文献
12.
Andrew Schamschurin David Uhrig Mark Fisher Stephen Clarke Janis Matisons 《Silicon Chemistry》2008,3(6):313-325
Dimethyl- and diphenylsilanediolates are key intermediates in the preparation of dimethyl- and diphenyl-siloxane polymers.
Both dimethyl- and diphenylsilanediolates R2Si(OM)2, where R = Me or Ph, and M = Li, Na and K were synthesised by the reaction between dimethyl- and diphenylsilanediol and a
metal or metal hydride (M/MH where M = Li, Na and K). The silanediolates were characterised by 29Si, 13C and 1H NMR, FTIR and mass spectroscopy. 相似文献
13.
The electrochemical solid phase micro-extraction of salicylic acid (SA) at graphite-epoxy-composed solid electrode surface
was studied by cyclic voltammetry. SA was oxidized electrochemically in pH 12.0 aqueous solution at 0.70 V (vs. saturated
calomel electrode) for 7 s. The oxidized product shows two surface-controlled reversible redox couples with two proton transferred
in the pH range of 1.0∼6.0 and one proton transferred in the pH range of 10.0∼13.0 and is extracted on the electrode surface
with a kinetic Boltzman function of i
p = 3.473–4.499/[1 + e(t − 7.332)/6.123] (χ
2 = 0.00285 μA). The anodic peak current of the extracted specie in differential pulse voltammograms is proportional to the
concentration of SA with regression equation of i
p = −5.913 + 0.4843 c (R = 0.995, SD = 1.6 μA) in the range of 5.00∼200 μM. The detection limit is 5.00 μM with RSD of 1.59% at 60 μM. The method
is sensitive and convenient and was applied to the detection of SA in mouse blood samples with satisfactory results. 相似文献
14.
Keiichi Satoh Toshio Suzuki Kiyoshi Sawada 《Monatshefte für Chemie / Chemical Monthly》2001,132(10):1145-1155
Summary. The molecular structures of bis-(pyridine base) complexes of cadmium(II) chloride and bromide, where the pyridine base is pyridine ( py), 3-methylpyridine (3-Me-py), 4-methylpyridine (4-Me-py), and 4-ethylpyridine (4-Et-py), were investigated by means of single-crystal X-ray diffraction and Raman spectroscopy. The crystal structures of CdCl2 py
2 (1), CdCl2(3-Me-py)2 (2), and CdCl2(4-Me-py)2 (3) were determined. All crystals are monoclinic; 1: a = 17.784(2), b = 8.666(1), c = 3.8252(7) ?, β = 91.54(1)°, space group: P21/n; 2: a = 11.89(1), b = 14.41(1), c = 3.874(6) ?, β = 92.3(1)°, space group: P21/a; 3: a = 21.091(2), b = 3.8884(5), c = 18.2317(3) ?, β = 113.64(1)°, space group: C2/c. The structures were refined to R/R
w
values (%) of 3.2/5.5, 3.0/5.0, and 3.4/5.1 for 1–3. All cadmium atoms are octahedrally coordinated with the chloride ions forming infinite di-μ-chloro polymeric linear chains
and the nitrogen atoms of the pyridine base in trans configuration. The Cd chains are oriented along the c-axis in 1 and 2 and along the b-axis in 3. The crystal structures indicate the absence of a peculiar interaction between the polymeric chains. The Raman spectra of eight complexes were measured in the range of 550–50 cm−1, and the Raman peaks originating from cadmium-halogen vibrations were assigned. The Raman spectra of 1 and 2 are quite alike in the lattice mode vibration region. The resemblance of the cadmium-halogen vibration peaks indicates the
same halogenide ion bridged octahedral structure for all complexes.
Received March 27, 2001. Accepted (revised) June 19, 2001 相似文献
15.
Bagheri H Aghakhani A Akbari M Ayazi Z 《Analytical and bioanalytical chemistry》2011,400(10):3607-3613
A micro-solid phase extraction technique was developed using a novel polypyrrole-polyamide nanofiber sheet, fabricated by
electrospinning method. The applicability of the new nanofiber sheet was examined as an extracting medium to isolate malathion
as a model pesticide from aqueous samples. Solvent desorption was subsequently performed in a microvial, and an aliquot of
extractant was injected into gas chromatography–mass spectrometry. Various parameters affecting the electrospinning process
including monomer concentration, polyamide content, applied voltage, and electrospinning time were examined. After fabricating
the most suitable preparation conditions, influential parameters on the extraction and desorption processes were optimized.
The developed method proved to be rather convenient and offers sufficient sensitivity and good reproducibility. The limit
of detection (S/N = 3) and limit of quantification (S/N = 10) of the method under optimized conditions were 50 and 100 ng L−1, respectively. The relative standard deviation at concentration level of 1 ng mL−1 was 2% (n = 3). The calibration curve of analyte showed linearity in the range of 0.1–1 ng mL−1 (R
2 = 0.9975). The developed method was successfully applied to tap and Zayanderood river water samples, while the relative recovery
percentages of 98% and 96% were obtained, respectively. The whole procedure showed to be conveniently applicable and quite
easy to be manipulated. 相似文献
16.
A kind of erbium hexacyanoferrate (ErHCF)-modified carbon ceramic electrodes (CCEs) fabricated by mechanically attaching ErHCF
samples to the surface of CCEs derived from sol–gel technique was proposed. The resulting modified electrodes exhibit well-defined
redox responses with the formal potential of +0.215 V [vs saturated calomel electrode (SCE)] at a scan rate of 20 mV s−1 in 0.5 M KCl (pH 7) solution. The voltammetric characteristics of the ErHCF-modified CCEs were investigated by voltammetry.
Attractively, the ErHCF-modified CCEs presented good electrocatalytic activity with a marked decrease in the overvoltage about
400 mV for l-cysteine oxidation. The calibration plot for l-cysteine determination was linear at 5.0 × 10−6–1.3 × 10−4 M with a linear regression equation of I(A) = 0.558 + 0.148c (μM) (R
2 = 0.9989, n = 20), and the detection limit was 2 × 10−6 M (S/N = 3). At last, the ErHCF-modified CCEs were used for amperometric detection of l-cysteine in real samples. 相似文献
17.
Malmstrøm J 《Analytical and bioanalytical chemistry》2012,403(4):1167-1177
Several electrospray mass spectrometry (ESI-MS) techniques have been described during the past years to enable the characterization
work of large poly(ethylene glycol)s (PEGs) and PEGylated proteins. The proton transfer reaction ESI-MS method utilizes amines
to charge reduce the electrospray envelope of PEGs, hence PEG molecules are aminated instead of protonated. This method simplifies
the mass spectrum of large PEGs, and enables the interpretation of the charge state of the observable envelopes (R ≥ 3,000 (FWHM) measured at the (M + 6H)6+ ion from 40 K PEG compound 7,324.19). Hence, deconvolution of the MS data can be performed and relative molecular masses
of the individual chain lengths of the PEGs can be calculated. However, as the poly-dispersity of PEGs may vary from batch
to batch and from sample to sample, it was of interest to examine if the method could distinguish between these kinds of different
material. Therefore, sample materials of each intermediate obtained at five synthetic steps during synthesis of a 40 kDa PEG
molecule were collected. These four intermediates, starting material and the target molecule were examined by 1H-NMR spectroscopy and ESI-MS using a proton stripping base. The study revealed that the charge-stripping ESI-MS method is
able to differentiate between even small changes in the structure of the polymeric molecules only when the analysis is assisted
by 1H-NMR spectroscopy. A proper characterization of polymer molecules requires besides relative molecular mass, also poly-dispersity
and end-group characterization. No end-group information is obtained based on MS data. Examination of the PEG polymers by
1H-NMR spectroscopy provides the needed information. In addition, the 1H-NMR spectra clearly distinguishes the examined polymers. 相似文献
18.
Srabanti Ghosh S. C. Bhattacharya Abhijit Saha 《Analytical and bioanalytical chemistry》2010,397(4):1573-1582
The gamma irradiation method has provided a route for synthesis of highly water-soluble, good-quality luminescent CdS/dendrimer
nanocomposites with amino- or carboxyl-terminated PAMAM dendrimer. An attempt has been made to probe ascorbic acid with the
as-synthesized CdS/dendrimer nanocomposites (DNC). Ascorbic acid (AA) is an important biological antioxidant and marker for
different diseases in clinical chemistry as well as in quality control in the food industry. Micromolar concentrations of
AA significantly quenched the photoluminescence (PL) of both amino (–NH2) and carboxylic (–COOH) functionalized semiconductor nanocomposites. The quenching followed a linear Stern–Volmer equation
and time-resolved photoluminescence spectroscopy confirmed its static nature. A strong size dependence of the quenching pattern
was observed. The binding constants, and the corresponding thermodynamic parameters ΔG
θ, ΔH
θ, ΔS
θ at different temperatures were calculated. CdS DNC showed selectivity towards ascorbic acid even in the presence of possible
interfering molecules, such as uric acid, tartaric acid and citric acid. Nanocomposites-based assay techniques could override
the complications involved in multitudes of assay procedures, providing a simple and fast new strategy for the quantification
of Ascorbic acid in the range of 16.6 to 100 μM (R = 0.998, n = 9). The proposed method was applied to the detection of ascorbic acid in Vitamin C tablets with satisfactory results. 相似文献
19.
Syed SU Hogan T Gibson J Taylor S 《Journal of the American Society for Mass Spectrometry》2012,23(5):988-995
This study uses a computer model to simulate a quadrupole mass filter (QMF) instrument under different operating conditions
for Mathieu stability zones 1 and 3. The investigation considers the factors that limit the maximum resolution (Rmax), which can be obtained for a given QMF for a particular value of scan line. Previously, QMF resolution (R) has been found
to be dependent on number (N) of radio frequency (rf) cycles experienced by the ions in the mass filter, according to R = N
n
/K, where n and K are the constants. However, this expression does not predict the limit to QMF resolution observed in practice and is true
only for the linear regions of the performance curve for QMF operation in zone 1 and zone 3 of the stability diagram. Here
we model the saturated regions of the performance curve for QMF operation in zone 1 according to R = q(1 – 2c
N
)/∆q, where c is a constant and ∆q is the width of the intersection of the operating scan line with the stability zone 1, measured at q-axis of the Mathieu stability diagram. Also by careful calculations of the detail of the stability tip of zone 1, the following
relationship was established between Rmax and percentage U/V ratio: R
max
= q/(0.9330-0.00933U/V). For QMF operation in zone 3 the expression R = a – bc
N
simulates well the linear and saturated regions of the performance curve for a range of operational conditions, where a,
b, and c are constants. 相似文献
20.
A rapid and universal bacteria-counting approach using CdSe/ZnS/SiO2 composite nanoparticles as fluorescence probe 总被引:1,自引:0,他引:1
In this paper, a rapid, simple, and sensitive method was described for detection of the total bacterial count using SiO2-coated CdSe/ZnS quantum dots (QDs) as a fluorescence marker that covalently coupled with bacteria using glutaraldehyde as
the crosslinker. Highly luminescent CdSe/ZnS were prepared by applying cadmium oxide and zinc stearate as precursors instead
of pyrophoric organometallic precursors. A reverse-microemulsion technique was used to synthesize CdSe/ZnS/SiO2 composite nanoparticles with a SiO2 surface coating. Our results showed that CdSe/ZnS/SiO2 composite nanoparticles prepared with this method possessed highly luminescent, biologically functional, and monodispersive
characteristics, and could successfully be covalently conjugated with the bacteria. As a demonstration, it was found that
the method had higher sensitivity and could count bacteria in 3 × 102 CFU/mL, lower than the conventional plate counting and organic dye-based method. A linear relationship of the fluorescence
peak intensity (Y) and the total bacterial count (X) was established in the range of 3 × 102–107 CFU/mL using the equation Y = 374.82X − 938.27 (R = 0.99574). The results of the determination for the total count of bacteria in seven real samples were identical with the
conventional plate count method, and the standard deviation was satisfactory. 相似文献