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1.
Summary Two procedures, based on large-volume injection with a programmed-temperature vaporizer (PTV), have been developed for the
determination of several triazine and organophosphorus pesticides. The use of PTV for injection in gas chromatography (GC)
has enabled the introduction of up to 200 μL sample extract into the GC, thus increasing the sensitivity of the method. PTV
injection has been combined off-line with two different microextraction procedures—liquid-liquid partition and solid-phase
extraction.
A simple and rapid off-line liquid-liquid microextraction procedure (5 mL water/1 mL methyltert-butyl ether) was applied to surface water samples spiked at levels between 0.01 and 5μg L−1. Recoveries of the overall procedure were >80% and the precision was better than 15%. Detection limits were <30 ngL−1 from 200-μL injections in GC-NPD analysis of triazines and GC-FPD analysis of organophosphorus pesticides. Off-line automated
solid-phase extraction with C18 cartridges has been applied to water samples (50 mL) spiked at 0.01, 0.1 and 1 μg L−1. The overall procedure was satisfactory (recoveries >80% and coefficients of variation <12%) and the limits of detection
ranged from 1 to 9 ng L−1.
Finally, several surface water samples were anlysed, and triazine herbicides were detected at concentrations of approx. 0.1–0.2
μg L−1. The results were similar to those obtained by conventional solvent extraction then GC-MSD after splitless injection of 2
μL. 相似文献
2.
Summary The potential of large-volume PTV injection was studied for the analysis of triazine herbicides in water samples. Direct water
injection and in-vial extraction were described and compared. Detection limits were between 0.01–0.02 μg L−1 and relative standard deviations were <9%. Both methods are suitable for the analysis of triazines at ppt-level, although
in-vial extraction is favourable for water samples with relatively large amounts of matrix components. 相似文献
3.
Determination of triazine herbicides in human body fluids by solid-phase microextraction and capillary gas chromatography 总被引:2,自引:0,他引:2
T. Kumazawa X. -P. Lee K. Kondo K. Sato H. Seno K. Watanabe-Suzuki A. Ishii O. Suzuki 《Chromatographia》2000,52(3-4):195-199
Summary Eight triazine herbicides, prometon, propazine, atrazine, simazine, prometryn, ametryn, metribuzin, and cyanazine, have been
extracted from human whole blood and urine samples by headspace solid-phase microextraction (SPME) with a polydimethylsiloxane-coated
fiber and quantified by capillary gas chromatography with nitrogen-phosphorus detection.
Extraction efficiencies for all compounds were 0.21–0.99% for whole blood, except for cyanazine (0.06%). For urine, the extraction
efficiencies for prometon, propazine, atrazine, prometryn and ametryn were 13.6–38.1%, and those of simazine, metribuzin and
cyanazine were 1.35–8.73%.
The regression equations for the compounds extracted from whole blood were linear within the concentration ranged 0.01–1 μg
(0.5 mL)−1 for prometon, propazine, atrazine, prometryn, and ametryn, and 0.02–1 μg (0.5 mL)−1 for simazine, metribuzin, and cyanazine. For urine, regression equations for all compounds were linear within the concentration
range 0.005–0.25 μg mL−1. Compound detection limits were 2.8–9.0 ng (0.5 mL)−1 and 0.4–2.0 ng mL−1 for whole blood and urine, respectively. The coefficients of within-day and day-to-day variation were satisfactory for all
the compounds, and not greater than 10.3 and 14.2%, respectively.
Data obtained from determination of atrazine in rat whole blood after oral administration of the compound are also presented. 相似文献
4.
De Souza D de Toledo RA Galli A Salazar-Banda GR Silva MR Garbellini GS Mazo LH Avaca LA Machado SA 《Analytical and bioanalytical chemistry》2007,387(6):2245-2253
The use of a copper solid amalgam electrode (CuSAE) for the analytical determination of triazine herbicides (atrazine and
ametryne) instead of the conventional hanging mercury drop electrode (HMDE) is reported. The results obtained using electroanalytical
methods utilizing each of these electrodes were also compared with those provided by the HPLC technique. The results indicated
that the CuSAE electrode can be used to detect the herbicides studied, since the detection limits reached using the electrode
(3.06 μg L−1 and 3.78 μg L−1 for atrazine and ametryne, respectively) are lower than the maximum values permitted by CONAMA (Brazilian National Council
for the Environment) for wastewaters (50 μg L−1) and by the US EPA (Environmental Protection Agency of the United States) in natural water samples (10.00 μg L−1). An electroanalytical methodology employing CuSAE and square wave voltammetry (SWV) was successfully applied to the determination
of atrazine and ametryne in natural water samples, yielding good recoveries (70.30%–79.40%). This indicates that the CuSAE
provides a convenient substitute for the HMDE, particularly since the CuSAE minimizes the toxic waste residues produced by
the use of mercury in HDME-based analyses. 相似文献
5.
Herranz S Ramón-Azcón J Benito-Peña E Marazuela MD Marco MP Moreno-Bondi MC 《Analytical and bioanalytical chemistry》2008,391(5):1801-1812
Specific polyclonal antibodies against s-triazine herbicides were obtained by preparing immunogens coupling home-synthesized haptens derivatives of simazine (6-chloro-N-ethyl-N′-ethyl-1,3,5-triazine-2,4-diamine) to lysine groups of hemocyanin from keyhole limpets and bovine serum albumin carrier proteins.
Three highly sensitive rabbit antisera were obtained and evaluated with a battery of six enzyme tracers derived from triazine
structures in an optimized ELISA format. The antiserum As8 and the HRP-2f tracer, which yield the best assay sensitivity for
simazine (detection limit 0.11 ± 0.02 μg L−1, IC50 0.88 ± 0.04 μg L−1), were applied to the development of a sensitive flow-through immunoassay for the analysis of this herbicide. The automated
assay was based on a direct competitive immunosorbent assay and fluorescence detection. The optimized method presents an IC50 value of 0.35 ± 0.04 μg L−1 with a detection limit of 1.3 ± 0.9 ng L−1 and a dynamic range from 0.010 to 7.5 μg L−1 simazine. The generic nature of the antiserum was shown by good relative cross-reactivities with other triazines such as
atrazine (420%) or propazine (130%) and a lower response to terbutylazine (6.4%) and desethyl-atrazine (2.2%). No cross-reactivity
was obtained for nonrelated pesticides such as 2,4-dichlorophenoxyacetic acid or linuron and the assay could be applied as
a screening method for triazine herbicides. The total analysis time was 30 min per determination and the immunosensor could
be reused for more than 150 cycles without significant loss of activity. The immunosensor has been successfully applied to
the direct analysis of simazine in surface water samples at the nanogram per liter level. The results obtained by comparative
analysis of the immunosensor with a chromatographic procedure for triazines showed a close correspondence. 相似文献
6.
E. W. J. Hooijschuur Ch. E. Kientz J. Dijksman U. A. Th. Brinkman 《Chromatographia》2001,54(5-6):295-301
Summary The potential of microcolumn liquid chromatography (μlC) and capillary electrophoresis (CE) with on-line, flame photometric
detection (FPD) in the P-selective mode has been studied for determination of polar P-containing pesticides, glyphosate and
its main metabolite, aminomethylphosphonic acid (AMPA), ethephon, fosetyl-aluminium and acephate. Acephate was determined
by reversed-phase μLLC-FPD using large-volume injections with peak compression, the other compounds were determined by μLC-FPD
and CE-FPD using simple, large-volume injection procedures to obtain limits of detection of 7.5-500 ng·mL−1 and 1.0 μ·mL−1, respectively. The methods showed acceptable repeatability and robustness and were successfully applied for rapid and selective
determination of pesticides in fruit, vegetable and water samples. 相似文献
7.
A highly sensitive and very simple spectrophotometric flow-injection analysis (FIA) method for the determination of iron(III)
at low concentration levels is presented. The method is based on the measurement of absorbance intensity of the red complex
at 410 nm formed by iron(III) and diphenylamine-4-sulfonic acid sodium salt (DPA-4-SA). It is a simple, highly sensitive,
fast, and low cost alternative method using the color developing reagent DPA-4-SA in acetate buffer at pH 5.50 and the flow-rate
of 1 mL min−1 with the sample throughput of 60 h−1. The method provided a linear determination range between 5 μg L−1 and 200 μg L−1 with the detection limit (3S) of 1 μg L−1 of iron(III) using the injection volume of 20 μL. FIA variables influencing the system performance were optimized. The amount
of iron(III) and total iron in river and seawater samples was successfully determined. Repeatability of the measurements was
satisfactory at the relative standard deviation of 3.5 % for 5 determinations of 10 μg L−1 iron(III). The accuracy of the method was evaluated using the standard addition method and checked by the analysis of the
certified material Std Zn/Al/Cu 43 XZ3F. 相似文献
8.
A simple and fast flow injection fluorescence quenching method for the determination of iron in water has been developed.
Fluorimetric determination is based on the measurement of the quenching effect of iron on salicylic acid fluorescence. An
emission peak of salicylic acid in aqueous solution occurs at 409 nm with excitation at 299 nm. The carrier solution used
was 2 × 10−6 mol L−1 salicylic acid in 0.1 mol L−1 NH4+/NH3 buffer solution at pH 8.5. Linear calibration was obtained for 5–100 μg L−1 iron(III) and the relative standard deviation was 1.25 % (n = 5) for a 20 μL injection volume iron(III). The limit of detection
was 0.3 μg L−1 and the sampling rate was 60 h−1. The effect of interferences from various metals and anions commonly present in water was also studied. The method was successfully
applied to the determination of low levels of iron in real samples (river, sea, and spring waters). 相似文献
9.
Summary Degradation products of chlorsulfuron, chlortoluron, diuron, fluometuron, isoproturon, linuron, metabenzthiazuron, metobromuron,
and monuron formed in the gas chromatographic injector have been used for identification of the respective herbicides. Mass
spectra of the derived compounds were obtained with a quadrupole mass spectrometric detector working in scan mode (20–450
amu). The compounds generated often depended on the solvent used for phenylurea herbicide injection (ethanol, methanol, dichloromethane,
and acetonitrile). When methanol and ethanol were used as solvents the major products formed from phenylureas were carbamic
acid esters. When acetonitrile or dichloromethane were used the main derivatives were phenylisocyanates. Chlorsulfuron and
metabenzthiazuron, however, generated a triazine plus a phenylsulfonamide and a benzothiazolamine, respectively, irrespective
of the solvent used. Linuron and diuron behaved similarly and gave degradation products with the same mass spectra. The thermal
reactions occurred instantaneously in the injector block and were promoted by the high temperature selected (300°C).
Detemination of the compounds derived from urea herbicides, by use of a 30 m BP10 column and a selected ion registering (SIR)
program based on two or three ions, can be used for sensitive detection of the presence of urea herbicides in environmental
extracts. With standards in methanol instrument detection limits ranged from 0.1 pg for chlorsulfuron (detected as 2-chlorobenzensulfonamide)
to 1 pg for monuron and metobromuron (both detected as their carbamic acid methyl esters).RSD were below 9% at the 5 ng L−1 level. The response was linearly dependent on quantily (r>0.9986) in the 5 ng L−1 to 25 μg L−1 range. Unequivocal identification of some phenylurea herbicides was not always possible because some herbicides with similar
structures, for example diuron and linuron, gave the same derivative. 相似文献
10.
Summary A simple and sensitive method for the determination of trace amounts of bisphenol-A (BPA), bisphenol-A diglycidyl dimethacrylate
(bis-GMA), bisphenol-A dimethacrylate (bis-DMA) and triethyleneglycol dimethacrylate (TEGDMA) in human saliva is proposed.
These materials are used in dental restorations, as composites and sealants, and are sometimes detected in human saliva after
dental treatment. The proposed method involves protein precipitation using acetonitrile followed by acidification, evaporation
of the solvent and dissolution with dichloromethane prior to injection into a GC-MS.
Thermal derivatization in the injection system was used for the identification and quantification of bis-GMA. Clean-up is
not necessary using SIM mode. Bisphenol-F (BPF) was used as internal standard. The linear range was 15 to 1000 μg·L−1 for BPA, 50 to 10 000 μg·L−1 for bis-GMA, 50 to 1000 μg·L−1 for bis-DMA and 1 to 100 μg·L−1 for TEGDMA.
The detection limits were 3,15,10 and 0.3 μg·L−1 for BPA, bis-GMA, bis-DMA and TEGD-MA, respectively. Validation of the proposed method was carried out by using the standard
addition methodology.
Samples of 10 mL of human saliva collected 1 h after dental treatment were analysed in order to assess the applicability of
the method to detect and quantify such compounds originated from methacrylic resins used in odontological treatment. 相似文献
11.
R. Jeannot H. Sabik L. Amalric E. Sauvard S. Proulx B. Rondeau 《Chromatographia》2001,54(3-4):236-240
Summary A method has been developed for determination of twenty-four polar pesticides—nine organophosphorus pesticides, thirteen organonitrogen
compounds, and two triazine degradation products—in surface water. It entails extraction of the target pesticides from 1-L
water samples by solid-phase extraction (SPE), then gas chromatography (GC) with large-volume (40 μL) injection. Filtered
surface water, from the St Lawrence River in Canada and the River Loire and its tributaries in France, was extracted on cartridges
filled with 500 mg Carbopack B (120–400 mesh). Analysis was performed by gas chromatography with a thermionic specific detector
(GC-TSD) and a mass spectrometric (MS) detector. Overall percentage recoveries were satisfactory (>70%) for all target pesticides,
with precision below 10%. Detection limits were between 0.5 and 4 ng L−1. 相似文献
12.
Summary AGC method has been developed for the analysis of tricholoroacetic acid (TCA) in water samples. It entails large-volume injection
(LVI) and programmed-temperature vaporization (PTV) of water samples, thermal decarboxylation of TCA to chloroform in the
injector, and GC-ECD analysis of the decarboxylation product. Conditions such as final injector temperature, splitless time,
and injection volume were optimized. The limit of detection is approximately 0.1 μg L−1 Several real samples were analyzed. The method presented is an easy means of determination of TCA and eliminates sample-preparation
steps such as extraction and derivatization. 相似文献
13.
Summary Selective on-line solid phase extraction (SPE) and liquid chromatography determination (HPLC) of diquat, paraquat and difenzoquat
from environmental water samples has been accomplished with Graphitized Carbon Black (GCB) as both extraction and analytical
columns. The method involved passing of 50 mL of water through a cartridge filled with Carbograph. In the elution step, the
herbicides were transferred from the cartridge to the analytical column (Hypercarb) by mean of a gradient of pH 3 aqueous
solution of tetramethylammonium hydroxide (TMAOH) and ammonium sulphate and methanol. Hypercarb columns were found to give
a low probability of false positives for bypiridylium herbicides and are very selective for polar compounds. Recovery was
better than 80 %. The breakthrough volume was studied with distilled water spiked with the herbicides at various concentration
levels (from 0.1 to 20 μg L−1). The limits of quantification of the method were lower than 0.1 μg L−1. The total analytical method was applied to surface waters from Torreblanca Nature Park (Castelló, Spain).
Presented at the 21st ISC held in Stuttgart, Germany, 15th–20th September, 1996. 相似文献
14.
Zhao RS Diao CP Wang X Jiang T Yuan JP 《Analytical and bioanalytical chemistry》2008,391(8):2915-2921
This paper describes a novel, simple and environmentally friendly method for rapid determination of the amide herbicides metoalchlor,
acetochlor, and butachlor. It is based on dispersive liquid-liquid microextraction and gas chromatography–mass spectrometry.
Factors that may influence the enrichment efficiency, such as type and volume of extraction solvent, type and volume of dispersive
solvent, extraction time, and content of NaCl, were investigated and optimized in detail. Under the optimum conditions, the
limits of detection of metoalchlor, acetochlor, and butachlor were 0.02, 0.04, and 0.003 μg L−1, respectively. The experimental results indicated that there was linearity over the range 0.1–50 μg L−1 and good reproducibility with relative standard deviations over the range 1.6–3.0% (n = 5). The proposed method has been applied for the analysis of real-world water samples, and satisfactory results were achieved.
Average recoveries of spiked herbicides were in the range 80.3–108.8%. All of these indicated that the developed method would
be an efficient method for simultaneous determination of the three herbicides in environmental water samples. 相似文献
15.
R. Rahnama Kozani Y. Assadi F. Shemirani M. R. Milani Hosseini M. R. Jamali 《Chromatographia》2007,66(1-2):81-86
Dispersive liquid–liquid microextraction (DLLME) has been used for preconcentration of trihalomethanes (THMs) in drinking
water. In DLLME an appropriate mixture of an extraction solvent (20.0 μL carbon disulfide) and a disperser solvent (0.50 mL
acetone) was used to form a cloudy solution from a 5.00-mL aqueous sample containing the analytes. After phase separation
by centrifugation the enriched analytes in the settled phase (6.5 ± 0.3 μL) were determined by gas chromatography with electron-capture
detection (GC–ECD). Different experimental conditions, for example type and volume of extraction solvent, type and volume
of disperser solvent, extraction time, and use of salt, were investigated. After optimization of the conditions the enrichment
factor ranged from 116 to 355 and the limit of detection from 0.005 to 0.040 μg L−1. The linear range was 0.01–50 μg L−1 (more than three orders of magnitude). Relative standard deviations (RSDs) for 2.00 μg L−1 THMs in water, with internal standard, were in the range 1.3–5.9% (n = 5); without internal standard they were in the range 3.7–8.6% (n = 5). The method was successfully used for extraction and determination of THMs in drinking water. The results showed that
total concentrations of THMs in drinking water from two areas of Tehran, Iran, were approximately 10.9 and 14.1 μg L−1. Relative recoveries from samples of drinking water spiked at levels of 2.00 and 5.00 μg L−1 were 95.0–107.8 and 92.2–100.9%, respectively. Comparison of this method with other methods indicates DLLME is a very simple
and rapid (less than 2 min) method which requires a small volume of sample (5 mL). 相似文献
16.
Summary An ion-chromatographic procedure is described for the determination of selenium (VI) at μg L−1 level in the presence of anions and heavy metal ions. Maximum permissible concentrations and effects from each interfering
substance were investigated for the Se concentration range 12.5–1,000 μg L−1. The method, optimized for the detection of SeO
4
2−
, gives results suitable for speciation analysis. Total selenium can be determined after complete conversion to selenate ion
by oxidation with KMnO4. The detection limit of selenium is 4.8 μg L−1 (0.96 ng for 200 μL sample).
Paper presented at the 41st Pittsburgh Conference, New York, March 5–9, 1990. 相似文献
17.
Summary An isocratic reversed-phase liquid chromatographic method for the simultaneous determination of hypericin and pseudohypericin,
two of the main constituents ofHypericum Perforatum L., has been developed. The compounds were eluted from an Inertsil ODS-3, column by triethylammonium acetate-methanol-acetonirile
(5:15:80) eluent and detected fluorimetrically, excitation 478, emission 598 nm. Hypericin and pseudohypericin were extracted
from flowring tops by Soxhlet and pseudohypericin was isolated from the extract by collecting its chromatographic peak from
the eluent flow. Identification of peaks was by HPLC coupled to a diode array detector and electrospray MS. The method was
applied to the determination of hypericin and pseudohypericin in plant extract and in pharmaceutical tablets. For the latter
a solid-phase extraction procedure was adopted. Riboflavin (0.1 ng.μL−1) was used as internal standard. The linear working range of the method is 0.025–4 ng.μL−1 and limit of detection 0.2 ng injected on-column. A comparative SPE study for hypericin is presented. 相似文献
18.
Th. Hankemeier J. Rozenbrand M. Abhadur J. J. Vreuls U. A. Th. Brinkman 《Chromatographia》1998,48(3-4):273-283
Summary A procedure is described for the (non-target) screening of hetero-atom-containing compounds in tap and waste water by correlating
data obtained by gas chromatography (GC) using atomic emission (AED) and mass selective (MS) detection. Solid-phase extraction
(SPE) was coupled on-line to both GC systems to enable the determination of microcontaminants at the 0.02–1 μg L−1 level in 7–50 mL of aqueous sample. The screening was limited to compounds present in at least one heteroatom-selective GC-AED
trace above a predetermined concentration level. These compounds were identified by their partial formulae (AED) and the corresponding
mass spectra, which were obtained from the GC-MS chromatogram via the retention index concept. The potential of the approach
was demonstrated by the identification of target compounds as well as all unknowns present in tap and waste water above the
predetermined threshold of 0.05 μg L−1 (tap water) or 0.5 μg L−1 (waste water). 相似文献
19.
Fernando Maya José Manuel Estela Víctor Cerdà 《Analytical and bioanalytical chemistry》2009,394(6):1577-1583
In this work, the hyphenation of the multisyringe flow injection analysis technique with a 100-cm-long pathlength liquid core
waveguide has been accomplished. The Cl−/Hg(SCN)2/Fe3+ reaction system for the spectrophotometric determination of chloride (Cl−) in waters was used as chemical model. As a result, this classic analytical methodology has been improved, minimizing dramatically
the consumption of reagents, in particular, that of the highly biotoxic chemical Hg(SCN)2. The proposed method features a linear dynamic range composed of two steps between (1) 0.2–2 and (2) 2–8 mg Cl− L−1, thus extended applicability due to on-line sample dilution (up to 400 mg Cl− L−1). It also presents improved limits of detection and quantification of 0.06 and 0.20 mg Cl− L−1, respectively. The coefficient of variation and the injection throughput were 1.3% (n = 10, 2 mg Cl− L−1) and 21 h−1. Furthermore, a very low consumption of reagents per Cl− determination of 0.2 μg Hg(II) and 28 μg Fe3+ has been achieved. The method was successfully applied to the determination of Cl− in different types of water samples. Finally, the proposed system is critically compared from a green analytical chemistry
point of view against other flow systems for the same purpose. 相似文献
20.
Comparison of adsorbents for on-line solid-phase extraction of polycyclic aromatic hydrocarbons before liquid chromatography with UV detection 总被引:1,自引:0,他引:1
Summary On-line solid-phase extraction (SPE) coupled with reversed-phase liquid chromatography and UV detection at 254 nm has been
used for the determination of trace-level polycyclic aromatic hydrocarbons (PAH) in soil extracts. Five commercially available
adsorbents (C8, C18, PLRP-S, PRP-1, and Bond-Elut Env) were evaluated. Results showed that recovery of the PAH decreased with increasing molecular
weight, because of their poorer solubility. Recovery of high-molecular-weight PAH was significantly improved by addition of
10% (v/v) acetonitrile to the sample before loading of the SPE adsorbent. PAH recovery ranged from 64.0 to 108% when a 50
mL sample spiked with 1 μg L−1 was applied to these adsorbents. Determination of PAH was possible with detection limits below 0.05 μg L−1, which corresponds to 0.2 μg kg−1 soil. The method was successfully used to determine PAH in soil extracts. 相似文献