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1.
Cinosi A Andriollo N Pepponi G Monticelli D 《Analytical and bioanalytical chemistry》2011,399(2):927-933
A total reflection X-ray fluorescence (TXRF) procedure was developed for the determination of metal traces in petrochemical
end products or intermediates for surfactant synthesis. The method combines a fast and straightforward sample preparation,
i.e. deposition on the sample holder and evaporation of the sample matrix, with an efficient quantification method based on
internal standardization (organic gallium standard). The method developed showed detection limits below 0.05 μg g-1 and in most cases below 0.005 μg g-1. Fifteen elements (Ca, Cd, Co, Cr, Cu, Fe, Mn, Mo, Ni, Pb, Rh, Sn, Sr, V and Zn) were determined in matrices such as paraffins,
n-olefins, linear alkylbenzenes, long-chain alkyl alcohols and esters: typical metal contents were below 1 μg g-1. The results were compared with the reference method ASTM D5708 (test method B) based on inductively coupled plasma optical
emission spectroscopy: advantages and drawbacks of the two procedures were critically evaluated. The TXRF method developed
showed comparable precision and absence of bias with respect to the reference method. A comparison of the performances of
the two methods is presented. 相似文献
2.
Tatyana S. Baptista Marcelo M. Redígolo Cibele B. Zamboni Ivone M. Sato Jose R. Marcelino 《Journal of Radioanalytical and Nuclear Chemistry》2012,291(2):399-403
The World Health Organization states that envenomation is responsible for a high number of deaths per year, especially in
equatorial areas. The only effective specific treatment is the use of hyperimmune serum (antivenom). In Brazil, Crioula breed
horses are used for antivenom production, with great importance in the maintenance of public health programs. A strict biochemical
and metabolic control is required to attain specificity in antiserum. Inorganic elements represent only a small fraction of
whole blood. Nonetheless, they play important roles in mammalian metabolism, being responsible for controlling enzymatic reactions,
respiratory and cardiac functions and ageing. In this work, whole blood samples from Crioula breed horses were analyzed by
EDXRF technique. The reference interval values were determined for the elements Na (1955–2013 μg g−1), Mg (51–75 μg g−1), P (523–555 μg g−1), S (1628–1730 μg g−1), Cl (2388–2574 μg g−1), K (1649–1852 μg g−1), Ca (202–213 μg g−1), Cu (4.1–4.5 μg g−1) and Zn (2.4–2.8 μg g−1) and a comparative study with NAA results was outlined. The samples were obtained from Instituto Butantan. Both techniques
showed to be appropriate for whole blood sample analyses and offer a new perspective in Veterinary Medicine. 相似文献
3.
Liu X Xu J Li Y Dong F Li J Song W Zheng Y 《Analytical and bioanalytical chemistry》2011,399(7):2539-2547
A sensitive and effective method for simultaneous determination of triazolopyrimidine sulfonamide herbicide residues in soil,
water, and wheat was developed using ultra-performance liquid chromatography coupled with tandem mass spectrometry. The four
herbicides (pyroxsulam, flumetsulam, metosulam, and diclosulam) were cleaned up with an off-line C18 SPE cartridge and detected
by tandem mass spectrometry using an electrospray ionization source in positive mode (ESI+). The determination of the target
compounds was achieved in <2.0 min. The limits of detection were below 1 μg kg−1, while the limits of quantification did not exceed 3 μg kg−1 in different matrices. Quantitation was determined from calibration curves of standards containing 0.05–100 μg L−1 with r
2 > 0.997. Recovery studies were conducted at three spiked levels (0.2, 1, and 5 μg kg−1 for water; 5, 10, and 100 μg kg−1 for soil and wheat). The overall average recoveries for this method in water, soil, wheat plants, and seeds at three levels
ranged from 75.4% to 106.0%, with relative standard deviations in the range of 2.1–12.5% (n = 5) for all analytes. 相似文献
4.
Jorge L. Guzmán Mar Leticia López Martínez Pedro L. López de Alba Nancy Ornelas Soto Víctor Cerdà Martín 《Journal of Radioanalytical and Nuclear Chemistry》2009,281(3):433-439
A multisyringe flow injection analysis method for the determination of uranium in water samples was developed. The methodology
was based on the complexation reaction of uranium with arsenazo (III) at pH 2.0. Uranium concentrations were spectrophotometrically
detected at 649 nm using a light emitting diode. Under the optimized conditions, a linear dynamic range from 0.1 to 4.0 μg mL−1, a 3σ detection limit of 0.04 μg mL−1, and a 10σ quantification limit of 0.10 μg mL−1 were obtained. The reproducibility (%) at 0.5, 2.5, and 4.0 μg mL−1 was 2.5, 0.9, and 0.6%, respectively (n = 10). The interference effect of some ions was tested. The proposed method was successfully applied to the determination
of uranium in water samples. 相似文献
5.
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
6.
Sangita Pal Suchismita Mishra S. K. Satpati G. G. Pandit P. K. Tewari V. D. Puranik 《Journal of Radioanalytical and Nuclear Chemistry》2011,289(1):67-73
A fast and simple multisyringe flow injection analysis (MSFIA) method for routine determination of thorium in water samples
was developed. The methodology was based on the complexation reaction of thorium with arsenazo (III) at pH 2.0. Thorium concentrations
were spectrophotometrically detected at 665 nm. Under optimal conditions, Beer’s law was obeyed over the range from 0.2 to
4.5 μg mL−1 thorium, a 3σ detection limit of 0.05 μg mL−1, and a 10σ quantification limit of 0.2 μg mL−1 were obtained. The relative standard deviations (RSD, %) at 0.5, 2.5 and 4.5 μg mL−1 was 2.8, 1.5 and 0.8%, respectively (n = 10). It was found that most of the common metal ions and anions did not interfere with the thorium determination. The proposed
method was successfully applied to its analysis in various water samples. 相似文献
7.
A. Pena L. J. G. Silva A. Pereira L. Meisel C. M. Lino 《Analytical and bioanalytical chemistry》2010,397(6):2615-2621
A total of 98 poultry samples, including chicken and turkey muscle, were analysed, using a sensitive and reliable analytical
method based on liquid chromatography (LC) with spectrofluorimetric detection, for simultaneous determination of four fluoroquinolone
(FQ) antibiotics, namely enrofloxacin (ENRO), ciprofloxacin (CIPRO), norfloxacin (NOR), and sarafloxacin (SARA). The method
involved extraction with 0.15 mol L−1 HCl and clean-up by solid-phase extraction using Oasis HLB cartridges. Chromatographic separation was carried out on a C18 TSK gel column, in isocratic mode, with 0.025 mol L−1 H3PO4 solution, adjusted to pH 3.0 with tetrabutylammonium hydroxide-methanol (78:22) as mobile phase. Good linearity over the
investigated concentration range was observed, with mean values of correlation coefficients higher than 0.9989 for all the
analytes studied. The limits of quantification (LOQ), expressed as the lowest fortification level with acceptable precision
were 15 μg kg−1 for ENRO, CIPRO, and NOR, and 30 μg kg−1 for SARA; these values are in compliance with requirements for monitoring of maximum residues levels (MRLs). Overall recoveries
from spiked samples ranged from 80% to 92% with relative standard deviations (RSD) lower than 6.1%. Of the chicken and turkey
samples analysed, 44.2% and 37.8%, respectively, were contaminated. The levels found in the analysed poultry samples, collected
from markets of Oporto and Coimbra, located in the north and central zones of Portugal, respectively, were lower than 114.2
and 87.6 μg kg−1 in chicken and turkey muscle samples, respectively. One positive chicken sample was contaminated with ENRO at levels higher
than the MRL. 相似文献
8.
Determination of nine high-intensity sweeteners in various foods by high-performance liquid chromatography with mass spectrometric detection 总被引:1,自引:0,他引:1
Zygler A Wasik A Kot-Wasik A Namieśnik J 《Analytical and bioanalytical chemistry》2011,400(7):2159-2172
An analytical procedure involving solid-phase extraction (SPE) and high-performance liquid chromatography-mass spectrometry
has been developed for the determination of nine high-intensity sweeteners authorised in the EU; acesulfame-K (ACS-K), aspartame
(ASP), alitame (ALI), cyclamate (CYC), dulcin (DUL), neohesperidin dihydrochalcone (NHDC), neotame (NEO), saccharin (SAC)
and sucralose (SCL) in a variety of food samples (i.e. beverages, dairy and fish products). After extraction with a buffer
composed of formic acid and N,N-diisopropylethylamine at pH 4.5 in ultrasonic bath, extracts were cleaned up using Strata-X 33 μm Polymeric SPE column. The
analytes were separated in gradient elution mode on C18 column and detected by mass spectrometer working with an electrospray source in negative ion mode. To confirm that analytical
method is suitable for its intended use, several validation parameters, such as linearity, limits of detection and quantification,
trueness and repeatibilty were evaluated. Calibration curves were linear within a studied range of concentrations (r
2
≥ 0.999) for six investigated sweeteners (CYC, ASP, ALI, DUL, NHDC, NEO). Three compounds (ACS-K, SAC, SCL) gave non-linear
response in the investigated concentration range. The method detection limits (corresponding to signal-to-noise (S/N) ratio
of 3) were below 0.25 μg mL−1 (μg g−1), whereas the method quantitation limits (corresponding to S/N ratio of 10) were below 2.5 μg mL−1 (μg g−1). The recoveries at the tested concentrations (50%, 100% and 125% of maximum usable dose) for all sweeteners were in the
range of 84.2 ÷ 106.7%, with relative standard deviations <10% regardless of the type of sample matrix (i.e. beverage, yoghurt,
fish product) and the spiking level. The proposed method has been successfully applied to the determination of the nine sweeteners
in drinks, yoghurts and fish products. The procedure described here is simple, accurate and precise and is suitable for routine
quality control analysis of foodstuffs. 相似文献
9.
A new adsorbent is proposed for the solid-phase extraction of phenol and 1-naphthol from polluted water. The adsorbent (TX-SiO2) is an organosilica composite made from a bifunctional immobilized layer comprising a major fraction (91%) of hydrophilic
diol groups and minor fraction (9%) of the amphiphilic long-chain nonionic surfactant Triton X-100 (polyoxyethylated isooctylphenol)
(TX). Under static conditions phenol was quantitatively extracted onto TX-SiO2 in the form of a 4-nitrophenylazophenolate ion associate with cetyltrimethylammonium bromide. The capacity of TX-SiO2 for phenol is 2.4 mg g−1 with distribution coefficients up to 3.4 × 104 mL g−1; corresponding data for 1-naphthol are 1.5 mg g−1 and 3 × 103 mL g−1. The distribution coefficient does not change significantly for solution volumes of 0.025–0.5 L and adsorbent mass less than
0.03 g; 1–90 μg analyte can be easily eluted by 1–3 mL acetonitrile with an overall recovery of 98.2% and 78.3% for phenol
and 1-naphthol, respectively. Linear correlation between acetonitrile solution absorbance (A
540) and phenol concentration (C) in water was found according to the equation A
540 = (6 ± 1) × 10−2 + (0.9 ± 0.1)C (μmol L−1) with a detection range from 1 × 10−8 mol L−1 (0.9 μL g−1) to 2 × 10−7 mol L−1 (19 μL g−1), a limit of quantification of 1 μL g−1 (preconcentration factor 125), correlation coefficient of 0.936, and relative standard deviation of 2.5%. A solid-phase colorimetric
method was developed for quantitative determination of 1-naphthol on adsorbent phase using scanner technology and RGB numerical
analysis. The detection limit of 1-naphthol with this method is 6 μL g−1 while the quantification limit is 20 μL g−1. A test system was developed for naked eye monitoring of 1-naphthol impurities in water. The proposed test kit allows one
to observe changes in the adsorbent color when 1-naphthol concentration in water is 0.08–3.2 mL g−1. 相似文献
10.
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
11.
Zang X Wang J Wang O Wang M Ma J Xi G Wang Z 《Analytical and bioanalytical chemistry》2008,392(4):749-754
A novel method was developed for the determination of captan, folpet, and captafol in apples by dispersive liquid–liquid microextraction
(DLLME) coupled with gas chromatography–electron capture detection (GC–ECD). Some experimental parameters that influence the
extraction efficiency, such as the type and volume of the disperser solvents and extraction solvents, extraction time, and
addition of salt, were studied and optimized to obtain the best extraction results. Under the optimum conditions, high enrichment
factors for the compounds were achieved ranging from 824 to 912. The recoveries of fungicides in apples at spiking levels
of 20.0 μg kg−1 and 70.0 μg kg−1 were 93.0–109.5% and 95.4–107.7%, respectively. The relative standard deviations (RSDs) for the apple samples at 30.0 μg kg−1 of each fungicide were in the range from 3.8 to 4.9%. The limits of detection were between 3.0 and 8.0 μg kg−1. The linearity of the method ranged from 10 to 100 μg kg−1 for the three fungicides, with correlation coefficients (r
2) varying from 0.9982 to 0.9997. The obtained results show that the DLLME combined with GC–ECD can satisfy the requirements
for the determination of fungicides in apple samples.
Figure Dispersive liquid–liquid microextraction (DLLME) coupled with gas chromatography–electron capture detection (GC–ECD) allows
satisfactory determination of fungicides in apple samples 相似文献
12.
An anodic stripping voltammetric procedure for the determination of Cu(II) at an in situ-plated stannum film electrode (SnFE)
was described. The results indicated that the SnFE had an attractive electroanalytical performance, with two distinct voltammetric
stripping signals for copper and stannum, and showed the superior advantage for the determination of copper compared with
the bismuth film electrode. Several experimental parameters were optimized. The SnFE exhibited highly linear behavior in the
concentration range from 1.0 to 100.0 μg L−1 of Cu(II) (r = 0.994) with the detection limit of 0.61 μg L−1 (S/N = 3), and the relative standard deviation for a solution containing 40.0 μg L−1 Cu(II) was 2.2% (n = 8). The procedure has been successfully applied for the determination of Cu(II) in lake water sample. 相似文献
13.
M. López-Sánchez M. J. Ayora-Cañada A. Molina-Díaz M. Siam W. Huber G. Quintás S. Armenta B. Lendl 《Analytical and bioanalytical chemistry》2009,394(8):2137-2144
A mid-infrared enzymatic assay for label-free monitoring of the enzymatic reaction of fructose-1,6-bisphosphatase with fructose
1,6-bisphosphate has been proposed. The whole procedure was done in an automated way operating in the stopped flow mode by
incorporating a temperature-controlled flow cell in a sequential injection manifold. Fourier transform infrared difference
spectra were evaluated for kinetic parameters, like the Michaelis–Menten constant (K
M) of the enzyme and V
max of the reaction. The obtained K
M of the reaction was 14 ± 3 g L−1 (41 μM). Furthermore, inhibition by adenosine 5′-monophosphate (AMP) was evaluated, and the K
MApp value was determined to be 12 ± 2 g L−1 (35 μM) for 7.5 and 15 μM AMP, respectively, with V
max decreasing from 0.1 ± 0.03 to 0.05 ± 0.01 g L−1 min−1. Therefore, AMP exerted a non-competitive inhibition. 相似文献
14.
D. G. Kelly K. M. Mattson K. S. Nielsen R. D. Weir S. D. White 《Journal of Radioanalytical and Nuclear Chemistry》2012,291(1):89-94
The analysis of antimony in soil is an important component in the assessment of environmental risk associated with the discharge
of munitions at small arms ranges. Proficiency testing samples associated with accreditation to the ISO 17025 standard have
been examined for their antimony content using Instrument Neutron Activation Analysis (INAA) and using microwave assisted
in situ hydrofluoric acid or nitric acid digestion, or nitrate ashing, followed by ICP-MS analysis. Data are compared with
the proficiency testing criteria associated with accreditation and with consensus data. All three techniques afford data which
are consistent with accredited analyses. However, the antimony concentrations obtained are method dependant, and generally
as follows; INAA > in situ HF > nitrate ashing > nitric acid. In situ HF data and nitrate ashing data are systematically higher
and lower than consensus values, respectively, but within the acceptable accreditation range. INAA is the only technique which
affords a concentration for antimony in the certified reference material PACS-2 (10.0 ± 0.1 μg g−1) which is not statistically different from its certified value (11.3 ± 1.3 μg g−1). 相似文献
15.
A. Pena M. Paulo L. J. G. Silva M. Seifrtová C. M. Lino P. Solich 《Analytical and bioanalytical chemistry》2010,396(8):2929-2936
This study investigated the occurrence of tetracyclines (TCs), namely minocycline (MIN), TC, and its epimer epitetracycline
(ETC), and doxycycline (DC), in four hospital wastewater effluents and its fate in municipal wastewater treatment plants (WWTPs),
in Coimbra, Portugal. Analytical determination was carried out by solid-phase extraction followed by liquid chromatography
with fluorescence detection. A gradient system with a mobile phase containing oxalic acid 0.02 M and acetonitrile was used.
After postcolumn derivatization with magnesium reagent, TCs were detected at λ
exc 386 nm and λ
em 500 nm. The proposed method allowed good sensitivity, accuracy, and precision. LOQs were 0.5 μg l−1 for ETC and TC and 15 and 5 μg l−1 for MIN and DC, respectively. The recovery values ranged between 66.4% and 117.1%, and intraday and interday repeatability
was lower than 6.8%. The method was successfully used to determine the presence of the above-mentioned TCs in 24 wastewater
composite samples obtained from hospital effluents and from influent and effluent of the WWTP located in Coimbra, Portugal.
MIN and TC were found in 41.7% of the samples; ETC and DC were found in 25% and 8.3% of the samples, respectively. The levels
found ranged from 6 to 531.7 μg l−1 in hospital effluents, while its concentrations in WWTP ranged from 95.8 to 915.3 μg l−1. A seasonal influence in the concentrations found has also been observed, the levels found in samples collected during spring
being higher than those observed in samples collected during autumn; however, these are only preliminary results. The WWTP
removal rate ranged between 89.5% and 100%. 相似文献
16.
Mohammad-Hossein Sorouraddin Masoud Saadati Ayyoub Aghaei 《Monatshefte für Chemie / Chemical Monthly》2011,63(9):439-445
Abstract
A selective optode based on immobilization of 5-(p-dimethylaminobenzylidene)rhodanine on a triacetylcellulose membrane was developed for quantitative determination of Au(III). The determination procedure was performed using a simple light-emitting diode (LED)-based device as a new effort to overcome low reproducibility and repeatability problems which usually accompany optode-based determinations. The results obtained were compared with those of conventional spectrophotometric methods. The response characteristics of the sensor including dynamic range, reproducibility, response time, and lifetime are discussed in detail. This sensor was used for the determination of Au(III) in ore and electroplating liquid effluent samples with satisfactory results in comparison with flame atomic absorption spectroscopy as standard method. Under the optimum conditions, the calibration plot was linear in the concentration range of 0.3–6.0 μg cm−3. The relative standard deviations for five replicate determinations of 1.0 μg cm−3 Au(III) and the corresponding limits of detection were 1.76% and 0.12 μg cm−3, respectively. 相似文献17.
Geraldo Capannesi Alberto Rosada Maurizio Manigrasso Pasquale Avino 《Journal of Radioanalytical and Nuclear Chemistry》2012,291(1):163-168
In geochemistry, the distribution of the Rare Earth Elements (REEs) in earth crust and mantle allows to understand geochemical
cycles and origin and age of igneous rocks. In this article REEs (Ce, Dy, Eu, La, Nd, Sm, Tb, and Yb), Th and U in ores of
the North-Latium (Bracciano area, Ceriti Mt., Fate Mt., Sabatini Mt., Vulsini Mt., Acqua Rossa basin), have been investigated
for evaluating the extraction feasibility for industrial applications. 107 samples were irradiated in the rotating rack of
the TRIGA Mark II reactor of the R.C. Casaccia (ENEA) at neutron flux of 2.6 × 1012
n × cm−2 × s−1 for 12 h together with primary and secondary standards. The gamma spectrometry measurements were performed after 8 h, 3 and
30 days of decay by means of HPGe detector (FWHM 1.75 keV at 1332.5 keV, peak/Compton ratio 55.1, relative efficiency of 22%)
connected to a multi-channel analyzer. The total REE mean content is 105 μg g−1, ranging widely between 2.23 and 410.5 μg g−1 (average coefficient of variation 112%). A similar behavior is found for Th and U: their average levels are 13.5 and 6.0 μg g−1, respectively. A quite good correlation between REEs and Th (and U) is found for Ceriti Mt. (r
2 > 0.8) whereas for the other areas the correlation is <0.7. The results obtained evidence the low U content in the investigated
locations. 相似文献
18.
Elif Ant Bursali Melek Merdivan Muruvvet Yurdakoc 《Journal of Radioanalytical and Nuclear Chemistry》2010,283(2):471-476
Olive cake as low-cost abundantly available sorbent has been characterized by N2 at 77 K adsorption, porosity analysis, elemental analysis and IR spectra and has been used for preconcentrating of uranium(VI)
and thorium(IV) ions prior to their determination spectrophotometrically. The optimum pH values for quantitative sorption
of U(VI) and Th(IV) are 4–7 and 3–7, respectively. The enrichment factor for the preconcentration of U(VI) and Th(IV) were
found to be 125 and 75 in the given order. The sorption capacity of olive cake is in the range of 2,260–15,000 μg g−1 for Th(IV) and in the range of 1,090–17,000 μg g−1 for U(VI) at pH 3–7. The sorbent exhibits good reusability and the uptake and stripping of the studied ions were fairly rapid.
The elution of U(VI) and Th(IV) was performed with 0.3–1 M HCl/1–2 M HNO3 and 0.3–0.8 M HCl/1 M HNO3, respectively. The precision of the method was 1.8 RSD% for U(VI) and 2.5 RSD% for Th(IV) in a concentration of 1.00 μg mL−1 for 10 replicate analysis. The influence of some electrolytes and cations as interferents was discussed. Separation of U(VI)
and Th(IV) from other metal ions in synthetic solution was achieved. 相似文献
19.
Lippolis V Pascale M Valenzano S Pluchinotta V Baumgartner S Krska R Visconti A 《Analytical and bioanalytical chemistry》2011,401(8):2561-2571
A rapid fluorescence polarization (FP) immunoassay has been developed for the simultaneous determination of T-2 and HT-2 toxins
in naturally contaminated wheat samples. Syntheses of four fluorescein-labelled T-2 or HT-2 toxin tracers were carried out
and their binding response with seven monoclonal antibodies was evaluated. The most sensitive antibody-tracer combination
was obtained by using an HT-2-specific antibody and a fluorescein-HT-2 tracer. The developed competitive FP immunoassay in
solution showed high cross-reactivity for T-2 toxin (CR% = 100%) while a very low CR% for neosolaniol (0.12%) and no cross-reactivity
with other mycotoxins frequently occurring in wheat. A rapid extraction procedure using 90% methanol was applied to wheat
samples prior to FP immunoassay. The average recovery from spiked wheat samples (50 to 200 μg kg−1) was 96% with relative standard deviation generally lower than 8%. A limit of detection of 8 μg kg−1 for the combined toxins was determined. Comparative analyses of 45 naturally contaminated and spiked wheat samples by both
the FP immunoassay and high-performance liquid chromatography/immunoaffinity clean-up showed a good correlation (r = 0.964). These results, combined with the rapidity (10 min) and simplicity of the assay, show that this method is suitable
for high throughput screening as well as for quantitative determination of T-2 and HT-2 toxins in wheat. 相似文献
20.
Microwave digestion and isotope dilution inductively coupled plasma mass spectrometry (ID-ICP-SFMS) has been applied to the
determination of Pb in rice flour. In order to achieve highly precise determination of low concentrations of Pb, the digestion
blank for Pb was reduced to 0.21 ng g−1 after optimization of the digestion conditions, in which 20 mL analysis solution was obtained after digestion of 0.5 g rice
flour. The observed value of Pb in a non-fat milk powder certified reference material (CRM), NIST SRM 1549, was 16.8 ± 0.8 ng
g−1 (mean ± expanded uncertainty, k = 2; n = 5), which agreed with the certified value of 19 ± 3 ng g−1 and indicated the effectiveness of the method. Analytical results for Pb in three brown rice flour CRMs, NIST SRM 1568a,
NIES CRM 10-a, and NIES CRM 10-b, were 7.32 ± 0.24 ng g−1 (n = 5), 1010 ± 10 ng g−1 (n = 5), and 1250 ± 20 ng g−1 (n = 5), respectively. The concentration of Pb in a candidate white rice flour reference material (RM) sample prepared by the
National Metrology Institute of Japan (NMIJ) was observed to be 4.36 ± 0.28 ng g−1 (n = 10 bottles).
Figure Digestion blank of Pb was carefully reduced to approximately 0.2 ng g-1 which permitted the highly precise determination of Pb at low ng g-1 level in foodstuff samples by ID-SFMS 相似文献