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1.
A solid-phase microextraction (SPME) method has been developed for the determination of 3 chloroacetanilide herbicides in both fresh and seawater samples. The extracted sample was analyzed by gas chromatography with mass spectrometry detection (GC-MS), and parameters affecting SPME operation including fibre type, sample pH, sample temperature, mixing speed and extraction time have been evaluated and optimized. The amount of dissolved organic matter (DOM) and the salt content both affected SPME extraction efficiency, but the presence of other competitive extractants such as organochlorine pesticides (OCPs) in the matrix showed no insignificance interference. The limit of detection (LOD) for acetochlor, metolachlor and butachlor were 1.2, 1.6 and 2.7 ng L−1, respectively. The recoveries for the herbicides ranged from 79 to 102%, and the linear dynamic range was from 10 to 1000 ng L−1. The developed method has been used to monitor herbicides contaminations in coastal water samples collected around Laizhou bay and Jiaozhou bay in Shandong peninsula, China. The concentrations of acetochlor and metolachlor ranged from undetectable to 78.5 ng L−1 and undetectable to 35.6 ng L−1, respectively. Butachlor was not observed but in only one sample and the concentration is lower than the limit of quantification (LOQ). The concentrations of the three herbicides in this study are low compared to most of the other places reported.  相似文献   

2.
An automated, confirmatory and sensitive procedure has been developed and validated for the determination of Sudan (I-IV), Sudan Orange G, Sudan Red 7B and Para Red in hot chilli food samples. The proposed method includes pressurised liquid extraction (PLE) with acetone, gel permeation chromatography (GPC) clean-up and detection by liquid chromatography (LC) coupled to electrospray ionization in positive mode tandem mass spectrometry (ESI-MS-MS). The main parameters affecting the performance of the different ionization sources and PLE parameters were previously optimised using statistical design of experiments (DOE). The method was in-house validated on chilli powder and chilli meat. Linear calibrations were obtained with correlation coefficients R2 > 0.999. The limits of detection (LOD) and quantification (LOQ) of the method were in the ranges of 0.002-0.012 ng g−1 and 0.006-0.036 ng g−1, respectively for chilli powder. The decision limit and detection capability were between 0.005-0.022 ng g−1 and 0.007-0.026 ng g−1, respectively for chilli meat. Recoveries ranged from 94% to 105%. The applicability of the method to the determination of azo-dyes in hot chilli products was demonstrated.  相似文献   

3.
The paper presents a new HPLC method, with UV and MSn detection, for the determination of seven pesticides, including the sulfonylurea herbicides amidosulfuron, azimsulfuron, nicosulfuron, rimsulfuron, thifensulfuron methyl, tribenuron methyl, and the fungicide azoxystrobin characterised by a methoxyacrilate structure. The methodology consists of a preconcentration/SPE (solid phase extraction) step and HPLC-UV (240 nm detection wavelength)-MSn analysis. Under the optimised conditions and after a 1000/1 preconcentration factor, the limits of detection were lower than 14.5 ng L−1 for UV detection and lower than 8.1 ng L−1 for MS detection. The limits of quantification were lower than 48.3 ng L−1 in UV detection and than 26.9 ng L−1 in MSn detection. The analysis of two samples, spiked with a mixture of the pesticides at threshold level concentrations, gave more than 60% recovery.  相似文献   

4.
A novel method based on the paired ion electrospray ionization (PIESI) mass spectrometry has been developed for determination of acidic pesticides at ultratrace levels in surface and ground waters. The proposed approach provides greatly enhanced sensitivity for acidic pesticides and overcomes the drawbacks of the less sensitive negative ion mode ESI-MS. The limits of detection (LODs) of 19 acidic pesticides were evaluated with four types of dicationic ion-pairing reagent (IPR) in both single ion monitoring (SIM) and selected reaction monitoring (SRM) mode. The LOD of 19 pesticides obtained with the use the optimal dicationic ion-pairing reagent ranged from 0.6 pg to 19 pg, indicating the superior sensitivity provided by this method. The transition pathways for different pesticide-IPR complexes during the collision induced dissociation (CID) were identified. To evaluate and eliminate any matrix effects and further decrease the detection limits, off-line solid-phase extraction (SPE) was performed for DI water and a river water matrix spiked with 2000 ng L−1 and 20 ng L−1 pesticides standards respectively, which showed an average percent recovery of 93%. The chromatographic separation of the acidic pesticides was conducted by high-performance liquid chromatography (HPLC) using a C18 column (250 mm × 2.1 mm) in the reversed phase mode using linear gradient elution. The optimized HPLC–PIESI-MS/MS method was utilized for determination of acidic pesticide at ng L−1 level in stream/pond water samples. This experimental approach is 1–3 orders of magnitude more sensitive for these analytes than other reported methods performed in the negative ion mode.  相似文献   

5.
Cao D  Wang Z  Han C  Cui L  Hu M  Wu J  Liu Y  Cai Y  Wang H  Kang Y 《Talanta》2011,85(1):345-352
Determination of perfluorinated compounds (PFCs) is very important because of their potential hazards to the environment and human health. In present work, 1,8-bis (tetramethylguanidino)-naphthalene (TMGN), a superbasic proton sponge, was firstly employed as the matrix for quantitative detection of acidic PFCs in environmental water samples by Matrix-assisted Laser Desorption/Ionization-Time of Flight Mass Spectrometry (MALDI-TOF-MS). Several acidic PFCs, such as perfluorooctanesulfonate (PFOS) and perfluorooctanoic acid (PFOA), were selected as model analytes for demonstrating the feasibility of the detection method. The results showed that deprotonated ions of these PFCs were detected without any other matrix ions interference. The achieved sensitivity with TMGN for PFOS detection was ten-fold higher than that with 1,8-bis (dimethyl-amino)-naphthalene (DMAN) which was used for the detection of fatty acid by MALDI-TOF-MS. The high sensitivity of this method made it feasible to monitor and quantify acidic PFCs in complicated environmental water samples. Furthermore, a novel combined strategy of solid phase extraction (SPE) followed by MALDI-TOF-MS detection was developed for quantifying PFCs in environmental water samples. The calibration curves with a wide linear dynamic range (0.1-10 ng L−1 for PFOS, PFHxS, and PFBS, and 0.5-50 ng L−1 for PFOA, PFNA, and PFDA.) were obtained. The limit of detection (LOD) for PFOS of this method was 0.015 ng L−1 (a signal-to-noise ratio of 3), which was lower than the LOD (0.036 ng L−1) obtained by high-pressure liquid chromatography/tandem mass spectrometry (LC-MS/MS) method. Moreover, the strategy was used to detect the selected PFCs in water samples collected from Xiaoqinghe river and Gaobeidian wastewater. The achieved concentrations of PFCs were closed to those obtained by LC-MS/MS method. It is indicated that the proposed MALDI-TOF-MS method with TMGN as the matrix is much reliable and can be used as an alternative method to detect trace PFCs in environmental water samples.  相似文献   

6.
Jihai Zhou 《Talanta》2009,79(2):189-1249
A CPE-HPLC (UV) method has been developed for the determination of Prometryne. In this method, non-ionic surfactant Triton X-114 was first used to extract and pre-concentrate Prometryne from water and soil samples. The separation and determination of Prometryne were then carried out in an HPLC-UV system with isocratic elution using a detector set at 254 nm wavelength. The parameters and variables that affected the extraction were also investigated and the optimal conditions were found to be 0.5% of Triton X-114 (w/v), 3% of NaCl (w/v) and heat-assisted at 50 °C for 30 min. Using these conditions, the recovery rates of Prometryne ranged from 92.84% to 99.23% in water and 85.48% to 93.67% in soil, respectively, with all the relative standard deviations less than 3.05%. Limit of detection (LOD) and limit of quantification (LOQ) were 3.5 μg L−1 and 11.0 μg L−1 in water and 4.0 μg kg−1 and 13.0 μg kg−1 in soil, respectively. Thus, we developed a method that has proven to be an efficient, green, rapid and inexpensive approach for extraction and determination of Prometryne from soil samples.  相似文献   

7.
A method for the determination of nine UV filter compounds [benzophenone-3 (BP-3), isoamyl methoxycinnamate, 4-methylbenzylidene camphor, octocrylene (OC), butyl methoxydibenzoylmethane, ethylhexyl dimethyl p-aminobenzoate (OD-PABA), ethylhexyl methoxycinnamate (EHMC), ethylhexyl salicylate and homosalate] in water samples was developed and evaluated. The procedure includes non-porous membrane-assisted liquid–liquid extraction (MALLE) and LC–atmospheric pressure photoionisation (APPI)–MS/MS. Membrane bags made of different polymeric materials were examined to enable a fast and simple extraction of the target analytes. Among the polymeric materials tested, low- and high-density polyethylene membranes proved to be well suited to adsorb the analytes from water samples. Finally, 2 cm length tailor-made membrane bags were prepared from low-density polyethylene in order to accommodate 100 μL of propanol. The fully optimised protocol provides recoveries from 76% to 101% and limits of detection (LOD) between 0.4 ng L−1 (OD-PABA) and 16 ng L−1 (EHMC). The interday repeatability of the whole protocol was below 18%. The effective separation of matrix molecules was proved by only marginal matrix influence during the APPI-MS analysis since no ion suppression effects were observed. During the extraction step, the influence of the matrix was only significant when non-treated wastewater was analysed. The analysis of lake water indicated the presence of seven UV filter compounds included in this study at concentrations between 40 ng L−1 (BP-3) and 4381 ng L−1 (OC). In non-treated wastewater several UV filters were also detected at concentration levels as high as 5322 ng L−1 (OC).  相似文献   

8.
Liquid chromatography (LC)/tandem mass spectrometry (MS/MS) after supramolecular solvent-based microextraction (SUSME) was firstly used in this work for the enantioselective determination of chiral pesticides in natural waters. The method developed for the quantitation of the R- and S-enantiomers of mecoprop (MCPP) and dichlorprop (DCPP) involved the extraction of the herbicides in a supramolecular solvent (SUPRAS) made up of reverse aggregates of dodecanoic acid (DoA), analyte re-extraction in acetate buffer (pH = 5.0), separation of the target enantiomers on a chiral column of permethylated α-cyclodextrin under isocratic conditions, and detection of the daughter ions (m/z = 140.9 and 160.6 for MCPP and DCPP, respectively) using a hybrid triple quadrupole mass spectrometer equipped with an electrospray source operating in the negative ion mode. Similar recoveries (ca. 75%) and actual concentration factors (ca. 94) were obtained for both phenoxypropanoic acids (PPAs). The quantitation limits were 1 ng L−1 for R- and S-MCPP, and 4 ng L−1 for R- and S-DCPP, and the precision, expressed as relative standard deviation (n = 6) was in the ranges 2.4–2.7% ([R-MCPP] = [S-MCPP] = 5 ng L−1 and [R-DCPP] = [S-DCPP] = 15 ng L−1) and 1.6–1.8% (100 ng L−1 of each enantiomer). The SUSME-LC–MS/MS method was successfully applied to the determination of the enantiomers of MCPP and DCPP in river and underground waters, fortified at concentrations between 15 and 180 ng L−1 at variable enantiomeric ratios (ER = 1–9).  相似文献   

9.
Enriching the surface density of immobilized capture antibodies enhances the detection signal of antibody sandwich microarrays. In this study, we improved the detection sensitivity of our previously developed P-Si (porous silicon) antibody microarray by optimizing concentrations of the capturing antibody. We investigated immunoassays using a P-Si microarray at three different capture antibody (PSA – prostate specific antigen) concentrations, analyzing the influence of the antibody density on the assay detection sensitivity. The LOD (limit of detection) for PSA was 2.5 ng mL−1, 80 pg mL−1, and 800 fg mL−1 when arraying the PSA antibody, H117 at the concentration 15 μg mL−1, 35 μg mL−1, and 154 μg mL−1, respectively. We further investigated PSA spiked into human female serum in the range of 800 fg mL−1 to 500 ng mL−1. The microarray showed a LOD of 800 fg mL−1 and a dynamic range of 800 fg mL−1 to 80 ng mL−1 in serum spiked samples.  相似文献   

10.
A novel dispersive liquid-liquid microextraction based on solidification of floating organic drop (DLLME-SFO) for separation/preconcentration of ultra trace amount of vanadium and its determination with the electrothermal atomic absorption spectrometry (ETAAS) was developed. The DLLME-SFO behavior of vanadium (V) using N-benzoyl-N-phenylhydroxylamine (BPHA) as complexing agent was systematically investigated. The factors influencing the complex formation and extraction by DLLME-SFO method were optimized. Under the optimized conditions: 100 μL, 200 μL and 25 mL of extraction solvent (1-undecanol), disperser solvent (acetone) and sample volume, respectively, an enrichment factor of 184, a detection limit (based on 3Sb/m) of 7 ng L−1 and a relative standard deviation of 4.6% (at 500 ng L−1) were obtained. The calibration graph using the preconcentration system for vanadium was linear from 20 to 1000 ng L−1 with a correlation coefficient of 0.9996. The method was successfully applied for the determination of vanadium in water and parsley.  相似文献   

11.
A high sensitive immunoassay-based lateral flow device for semi-quantitatively determine aflatoxin M1 (AFM1) in milk was developed. Investigation and optimization of the competitor design and of the gold-labelling strategy allowed the attainment of the ultra-sensitive assessment of AFM1 contamination at nanograms per litre level (LOD 20 ng L−1, IC50 99 ng L−1), as requested by European regulations. A one order of magnitude detectability enhancement in comparison to previously reported gold colloid immunochromatographic assays for this toxin was obtained.  相似文献   

12.
Elci L  Kolbe N  Elci SG  Anderson JT 《Talanta》2011,85(1):551-555
Solid-phase extraction (SPE) followed by derivatization and gas chromatography-atomic emission detection (GC-AED) was evaluated for the determination of five chlorophenols (CPs) in water samples. The derivatization was based on the esterification of phenolic compounds with ferrocenecarboxylic acid. The determination of the derivatized phenols was performed by GC-AED in the iron selective detection mode at 302 nm. The described method was tested on spiked water samples.The overall method gave detection limits of 1.6-3.7 ng L−1 and recoveries of 90.9-104.5% for the examined mono- to trichlorophenols in 10 mL water samples. The CPs extracted from a 10 mL water sample with SPE were concentrated into 100 μL of organic solvent, a preconcentration factor of 100. The method was applied to lake and tap water samples, and CP contents between 6 and 51 ng L−1 in lake water and between below the detection limit and 8 ng L−1 in tap water were found for different CPs. The method is quick, simple and gives excellent recoveries, limits of detection and standard deviations.  相似文献   

13.
A sensitive and specific method was developed and validated for the determination of estrogen and xenoestrogen in surface waters using liquid chromatography followed by tandem mass spectrometry. Chromatographic separation was performed using ammonium hydroxide solutions in water and in methanol as mobile phase. Compounds were determined in a triple quadrupole mass spectrometer equipped with an electrospray ionization interface operating in the negative mode. Multiple reaction monitoring conditions were optimized for estrone, 17β-estradiol, estriol, 17α-ethinylestradiol, bisphenol A, 4-n-octylphenol, and 4-n-nonylphenol. The method was linear from 0.1 ng L− 1 to 10 µgL− 1. Limits of quantification varied between 0.1 and 3.1 ng L− 1 and recoveries for a 50 ng L− 1 spiked-surface water solution varied between 72 and 140%. The method was successfully used to determine estrogen and xenoestrogen levels in Brazilian water samples collected along the Atibaia River Basin, in the State of São Paulo. Concentrations of estrogens varied from 2.2 to 39 ng L− 1. Bisphenol A was the most frequently detected compound as well as the only xenoestrogen in the samples with concentrations between 25 and 84 ng L− 1.  相似文献   

14.
In this work, the determination of total As in seawater by hydride generation atomic fluorescence spectrometry was studied. The influence of the chemical, flow and instrumental parameters were investigated and optimized. The pre-reduction of As(V) to As(III) was performed using KI plus ascorbic acid in 3.5 mol L− 1 HCl medium. No multiplicative interference was present and external aqueous calibration could be used. The limit of detection was 36 ng L− 1, while the repeatability was 2% (n = 10), at a 500 ng L− 1 concentration level. The sample throughput was 15 h− 1 if triplicate measurements were made. The accuracy was assessed by the analysis of a seawater certified reference material and excellent agreement between the obtained and certified values was verified. The procedure was used for the analysis of seawater offshore samples collected at the Brazilian coast and results ranging from 860 to 1200 ng L− 1 were found.  相似文献   

15.
A simple chiral high-performance liquid chromatography (HPLC) method with ultraviolet (UV) and circular dichroism (CD) detection was developed and validated for measuring benalaxyl enantiomers using (R,R) Whelk-O 1 column. The effects of mobile phase composition and column temperature on the entioseparation were investigated. A CD detector was used to determine the elution order of the enantiomers. Excellent resolution was easily obtained using n-hexane-polar organic alcohols mobile phase. The chiral recognition mechanism was also discussed. Based on the developed chiral HPLC method, enantioselective analysis methods for this fungicide in environment matrix (soil and water) were developed and validated. Good linearities were obtained over the concentration range of 0.25-25 mg L−1 for both enantiomers. Liquid-liquid extraction and solid phase extraction (SPE) were used for the enrichment and cleanup of soil and water samples. Recoveries for the two enantiomers were 79-91% at 0.02, 0.04 and 0.2 mg kg−1 levels from soil, and 89-101% at 0.0025, 0.01 and 0.05 mg L−1 levels from water. Run-to-run and day-to-day assay precisions were below 10% for both enantiomers at concentrations of 0.5, 1 and 5 mg L−1. Individual detection limits of the two enantiomers were both 2 ng. Limits of detection (LOD) were 0.004 mg kg−1 in soil and 0.001 mg L−1 in water.  相似文献   

16.
Non-chromatographic speciation of toxic arsenic in fish   总被引:1,自引:0,他引:1  
A rapid, sensitive and economic method has been developed for the direct determination of toxic species of arsenic present in fish and mussel samples. As(III), As(V), dimethylarsinic acid (DMA), and monomethylarsonic acid (MMA) were determined by hydride generation-atomic fluorescence spectrometry using a series of proportional equations without the need of a chromatographic previous separation. The method is based on the extraction of arsenic species from fish through sonication with HNO3 3 mol l−1 and 0.1% (m/v) Triton and washing of the solid phase with 0.1% (m/v) EDTA, followed by direct measurement of the corresponding hydrides in four different experimental conditions. The limit of detection of the method was 0.62 ng g−1 for As(III), 2.1 ng g−1 for As(V), 1.8 ng g−1 for MMA and 5.4 ng g−1 for DMA, in all cases expressed in terms of sample dry weight. The mean relative standard deviation values (R.S.D.) in actual sample analysis were: 6.8% for As(III), 10.3% for As(V), 8.5% for MMA and 7.4% for DMA at concentration levels from 0.08 mg kg−1 As(III) to 1.3 mg kg−1 DMA. Recovery studies provided percentages greater than 93% for all species in spiked samples. The analysis of SRM DORM-2 and CRM 627 certified materials evidenced that the method is suitable for the accurate determination of arsenic species in fish.  相似文献   

17.
A new methodology was developed for the determination of ultratrace levels of gold in water samples, soils and river sediments. Dispersive liquid-liquid microextraction was used to preconcentrate the ion pair formed between AuCl4 and [CH3(CH2)3]4N+ in a microliter-range volume of chlorobenzene using acetone as disperser solvent. When solid samples were analyzed, the method consisted of a combination of ultrasound-assisted extraction and dispersive liquid-liquid microextraction with final detection by electrothermal-atomic absorption spectrometry. Since an HCl medium was required for the formation of the AuCl4 complex, HCl together with HNO3 was used as extractants for ultrasound-assisted extraction. After optimization, the enrichment factor obtained was 220 for water samples. Moreover, the extraction efficiency was around 96%. The repeatability, expressed as relative standard deviation ranged from 3.6% to 9.7%. The instrumental detection limit was 8.4 ng L−1, whereas the procedural detection limits were 42 ng L−1 for water samples and 1.5 ng g−1 for environmental solid samples.  相似文献   

18.
A new micelle-mediated phase preconcentration method for preconcentration of ultra-trace quantities of beryllium as a prior step to its determination by spectrophotometry has been developed. Chrome Azurol S (CAS) and cetyltrimethylammonium bromide (CTAB) were used as chelating agent and cationic surfactant, respectively. The method evaluates and eliminates the blank bias error present in such procedures using mean centering of ratio spectra. This procedure gives more accurate results than the traditional approach using absorbance values against reagent blank. The optimal extraction and reaction conditions were studied and the analytical characteristics of the method (e.g., limit of detection, linear range, preconcentration and improvement factors) were obtained. Linearity was obeyed in the range of 0.9-18.0 ng mL−1 (1.00 × 10−7-2.00 × 10−6 mol L−1) of beryllium. The detection limit of the method is 0.51 ng mL−1 (5.66 × 10−8 mol L−1) of beryllium. The interference effect of some anions and cations was also tested. The method was applied to the determination of beryllium in spring water samples.  相似文献   

19.
Zhang Y  He F  Wan Y  Meng M  Xu J  Yi J  Wang Y  Feng C  Wang S  Xi R 《Talanta》2011,83(3):732-737
Trenbolone (TRE) is a steroid used by veterinarians on livestock to increase appetite and body weight. The use of TRE has been restricted because of its harmful side effect for consumers. To effectively control TRE residue in food and food product, a rapid and convenient immunoassay was developed by preparing an anti-TRE monoclonal antibody. The immunogen and coating antigen were prepared by coupling TRE hapten with carrier proteins via 1-ethyl-3-(dimethylaminopropyl)carbodiimide hydrochloride (EDC) method. The optimized method gave an average IC50 value of 0.323 ng mL−1 towards TRE and an average detection limit (LOD) of 0.06 ng mL−1, which is much lower than the maximum residue levels (2.0 ng g−1) accepted by the Joint FAO/WHO Expert Committee on Food Additives (JECFA). The specificity of the antibody was evaluated by measuring cross-reactivity of six structurally related compounds, including 19-nortestosterone (9.7%), testosterone (0.13%), methyltestosterone (<0.01%), methandrostenolone (<0.01%), (+)-dehydroisoandrosterone (<0.001%) and β-estradiol (<0.001%). The recovery rates of the test in detection of TRE-fortified animal tissue, urine and animal feed samples were in the range of 81.3-89.4%, while the intra- and inter-assay coefficients of variation were less than 12.0%.  相似文献   

20.
In this work the development and validation of a new procedure for the simultaneous determination of 9 nitro and polycyclic musk compounds: musk ambrette (MA), musk ketone (MK), musk mosken (MM), celestolide (ADBI), phantolide (AHMI), tonalide (AHTN), traseolide (ATII), cashmeran (DPMI) and galaxolide (HHCB) in environmental water samples (estuarine and wastewater) using microextraction by packed sorbent (MEPS) followed by large volume injection-gas chromatography–mass spectrometry (LVI-GC–MS) was carried out. Apart from the optimization of the different variables affecting MEPS (i.e., nature of the sorbent, nature of the solvent elution, sample load, and elution/injection volume) extraction recovery was also evaluated, not only for water samples but also for environmental water matrices such as estuarine and waste water. The use of two deuterated analogs ([2H3]-AHTN and [2H15]-MX) was successfully evaluated in order to correct matrix effect in complex environmental matrices such as influent samples from wastewater treatment plants. Method detection limits (MDLs) ranged from 5 to 25 ng L−1, 7 to 39 ng L−1 and 8 to 84 ng L−1 for influent, effluent and estuarine samples, respectively. Apparent recoveries were higher than 75% for all target compounds in all the matrices studied (estuarine water and wastewater) and the precision of the method, calculated as relative standard deviation (RSD), was below 13.2% at 200 ng L−1 concentration level and below 14.9% at low level (20 ng L−1 for all the target analytes, except for AHTN which was set at 40 ng L−1 and HHCB at 90 ng L−1, due to the higher MDL values presented by those target compounds). Finally, this MEPS procedure was applied to the determination of the target analytes in water samples, including estuarine and wastewater, from two estuaries, Urdaibai (Spain) and Adour (France) and an established stir-bar sorptive extraction-liquid desorption/large volume injection-gas chromatography–mass spectrometry (SBSE-LD/LVI-GC–MS) method was performed in parallel for comparison. Results were in good agreement for all the analytes determined, except for DPMI.  相似文献   

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