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1.
建立了动物源性食品猪肉、牛肉、鸡肉及鱼肉中36种有机磷农药残留的快速分析方法。以乙腈作为溶剂,对试样采用加速溶剂萃取仪萃取,自动凝胶渗透色谱仪净化预处理,N-丙基乙二胺(PSA)填料再净化,毛细管气相色谱法分离,火焰光度检测器(磷型)检测,内标法定量。该方法分离效果良好,重现性好,灵敏度、精密度高,杂质干扰少。36种有机磷农药的检测限(LOD)为0.0012 mg/kg(乙拌磷)~0.014 mg/kg(吡唑硫磷),定量限(LOQ)为0.004 mg/kg(乙拌磷)~0.047 mg/kg(吡唑硫磷)。当试样中有机磷农药的添加浓度分别为0.05,0.1,0.2 mg/kg时,回收率为58.2%~106.3%。方法的最低检测限和添加回收率均符合农药残留分析的要求。 相似文献
2.
A procedure for the determination of dialkyphosphorus metabolites of organophosphorus pesticides in human blood has been worked out. Dimethyl and diethyl phosphates, phosphorothioates and phosphorodithioates, extracted with diethyl ether from plasma acidified with hydrochloric acid, were methylated with diazomethane and analysed by capillary gas chromatography with an alkali flame ionization detector and an ion trap detector. The extraction of metabolites was preceded by n-hexane extraction of parent organophosphorus pesticides without a negative effect on the efficiency of metabolite extraction. If plasma samples, containing 2 μ/ml of each metabolite, were not saturated with sodium chloride before extraction, only dialkyl phosphorothioates were recovered by more than 80%. The recoveries of other metabolites were less than 25%. The extraction of plasma samples saturated with sodium chloride resulted in higher recoveries of all metabolites. At concentrations ranging from 0.2 to 2.8 μg/ml the accumulation effeciencies (%±S.D.) of dimethyl and diethyl phosphorothioates were 92±20 and 97±11, and those of corresponding phosphorodithiotes 79±7 and 71±4. A significantly lower recovery (36±12%) was determined for dimethyl phosphate at concentrations in plasma below 2 μg/ml. The recovery of diethyl phosphate was dependent on the initial metabolite concentration in plasma being 31±5% at concentrations lower than 0.5 μg/ml, 51±12% at concentrations ranging from 0.7 to 1.7 μg/ml and 97±3% at concentrations at or above 2 μg/ml. Detection limits of metabolites in plasma using the phosphorus selective detector were 150 ng/ml for dimethyl phosphate and 50 ng/ml for other metabolites. Those values were for dialkyl phosphates and phophorothioates three to five times lower and for diakyl phosphorodithiotes even 30 times lower than detection limits achieved by the use of ion trap detector. The procedure was applied for the evidence and confirmation of human poisoning with organophosphorus pesticides. 相似文献
3.
An overview of analytical methodology for the determination of organophosphate pesticides residues in foods is presented. Sample extraction is carried out with acetone followed by a dichloromethane-hexane partition. The organic extract is purified by automated gel permeation chromatography and analysed by capillary gas chromatography with flame photometric or thermionic detection. Confirmation can be carried out by a variety of chemical derivatization techniques including hydrolysis followed by reaction of the phosphate or phenol moiety, direct alkylation or trifluoracetylation. Thin-layer chromatography with enzyme inhibition detection can be used as a rapid screening technique or to confirm results obtained by gas chromatography. Liquid chromatography has not been used much for the determination of organophosphorus compounds in foods. 相似文献
4.
The suitability of Empore-activated carbon disks (EACD), Envi-Carb graphitized carbon black (GCB) and CPP-50 graphitized carbon for the trace enrichment of polar pesticides from water samples was studied by means of off-line and on-line solid-phase extraction (SPE). In the off-line procedure, 0.5-2 1 samples spiked with a test mixture of oxamyl, methomyl and aldicarb sulfoxide were enriched on EnviCarb SPE cartridges or 47 mm diameter EACD and eluted with dichloromethane-methanol. After evaporation, a sample was injected onto a C 18-bonded silica column and analysed by liquid chromatography with ultraviolet (LC-UV) detection. EACD performed better than EnviCarb cartridges in terms of breakthrough volumes (>2 1 for all test analytes), reproducibility (R.S.D. of recoveries, 4–8%, n=3) and smapling speed (100 ml/min); detection limits in drinking water were 0.05–0.16 μg/l. In the on-line experiments, 4.6 mm diameter pieces cut from original EACD and stacked onto each other in a 9 mm long precolumn, and EnviCarb and CPP-50 packed in 10×2.0 mm I.D. precolumn, were tested, and 50–200 ml spiked water samples were preconcentrated. Because of the peak broadening caused by the strong sorption of the analytes on carbon, the carbon-packed precolumns were eluted by a separate stream of 0.1 ml/min acetonitrile which was mixed with the gradient LC eluent in front of the C 18 analytical column. The final on-line procedure was also applied for the less polar propoxur, carbaryl and methiocarb. EnviCarb could not be used due to its poor pressure resistance. CPP-50 provided less peak broadening than EACD: peak widths were 0.1–0.3 min and R.S.D. of peak heights 4–14% ( n = 3). In terms of analyte trapping efficiency on-line SPE-LC-UV with a CPP-50 precolumn also showed better performance than when Bondesil C 18/OH or polymeric PLRP-S was used, but chromatographic resolution was similar. With the CPP-50-based system, detection limits of the test compounds were 0.05–1 μg/l in surface water. 相似文献
5.
采用微量化学法和全自动固相萃取技术 ,建立了气相色谱法同时测定茶叶中 14种有机磷农药残留量的方法 ,并对样品的前处理作了一定的探讨。结果表明 ,采用程序升温 ,所测定的 14种有机磷农药在SPBTM 170 1石英毛细管柱上得到了很好的分离 ,且方法快速、灵敏 ,完全符合实际应用需要。 相似文献
6.
A multiresidue, automated and rapid method for the determination of pesticide residues in olive oil is presented. The method employs the through oven transfer adsorption-desorption interface for the on-line coupling of reversed-phase liquid chromatography and gas chromatography. In this fully automated system, olive oil is directly injected with no sample pre-treatment step other than filtration. Methanol-water is used as eluent in the liquid chromatography pre-separation step. The selected liquid chromatography fraction containing the pesticides is automatically transferred to the gas chromatography. The liquid chromatography column flow during elution is different from the flow during the transfer. Using a flame ionisation detector, pesticide detection limits varied from 0.1 to 0.3 mg/l. 相似文献
7.
A rapid and simple method using accelerated solvent extraction and solid-phase extraction cleanup was developed and validated for the determination of 15 organophosphorus pesticides in ginkgo leaves by capillary gas chromatography with flame photometric detection. The pesticides were extracted at 100 degrees C under 1500 psi pressure in <20 min. The average recovery from 10 g ginkgo leaves, fortified at 3 levels ranging from 0.05 to 1.00 mg/kg, was 95.2% with a relative standard deviation of 4.6%. The limits of detection ranged from 1.11 x 10(-3) mg/kg (dimethoate) to 4.44 x 10(-3) mg/kg (dichlorvos). The proposed method showed acceptable accuracy and precision while minimizing environmental concerns, time, and labor. Furthermore, the method could be easily applied to the monitoring of these 15 organophosphorus pesticides in ginkgo leaves. 相似文献
8.
Microcolumn liquid chromatography (micro-LC) of some chiral organophosphorus pesticides has been studied using Chiralcel OD columns and simultaneous ultraviolet (UV) and phosphorus selective detection, the latter by means of a micro-UV cell coupled on-line to a thermionic detector (TID). Micro-LC showed a ca. 5-fold improved separation impedance, a ca. 1.8-fold increased column permeability, and greater inertness compared with conventional LC. By using the TID, organophosphorus pesticides could be satisfactorily determined at trace levels, the detection limit being 4 pg/s of phosphorus. The response of the micro-LC-TID system is linear in the range of 0.05–20 ng ( r = 0.9994). 相似文献
9.
Summary Packed-capillary, supercritical fluid chromatography using carbon dioxide modified with methanol or 2-propanol as mobile phase, was coupled with a thermionic detector for phosphorus-selective detection. Optimum conditions for thermionic detection were established for a number of hydrogen flow rates by adjusting the air flow rate and bead position. Using the mentioned modifiers, a series of organophosphorus pesticides of varying polarity could be separated within 8 min. An optimum sensitivity of 55–128 fg P/s and linearity over four orders of magnitude were obtained. The detector showed good selectivity for phosphorus over carbon and nitrogen, viz., 9·10 4 g C/g P and 75 g N/g P, respectively. This was demonstrated by determining pesticides such as phoxim, dimethoate and azinphos-methyl in onion and tomato extracts. 相似文献
10.
采用反吹技术改进了气相色谱检测大批量蔬菜样品中有机磷农药残留的方法。在样品中加入乙腈、氯化钠混合溶液振荡,离心分层,得到乙腈提取液。取部分提取液浓缩、定容,用配备火焰光度检测器及微流控装置的气相色谱仪进行有机磷农药检测。16种有机磷农药在0.040~3.20 mg/L内具有良好的线性关系(r>0.9996)。回收率为75.2%~111.5%,相对标准偏差为2.8%~10.4%,检出限为0.003~0.01 mg/kg。通过反吹可以有效降低基质效应影响,缩短每个样品的运行时间,减少停机维护和材料消耗,节约38%的检测时间。 相似文献
11.
A fully automated at-line solid-phase extraction-gas chromatography procedure has been developed for the analysis of aqueous samples using the PrepStation. The sample extract is transferred from the sample preparation module to the gas chromatograph via an autosampler vial. With flame-ionization detection, limits of determination ( S/ N=10) of 0.05–0.13 μg/l were obtained for the analysis of HPLC-grade water when modifying the PrepStation by: (i) increasing the sample volume to 50 ml, (ii) increasing the injection volume up to 50 μl, and (iii) decreasing the desorption volume to 300 μl. The HP autosampler had to be modified to enable the automated “at-once” on-column injection of up to 50 μl of sample extract. The amount of packing material in the original cartridge had to be reduced to effect the decrease of the desorption volume. The total set-up did not require any further optimization after having set up the method once. The analytical characteristics of the organonitrogen and organophosphorus test analytes, i.e. recoveries (typically 75–105%), repeatability (2–8%) and linearity (0.09–3.0 μg/l) were satisfactory. The potential of the system was demonstrated by determining triazines and organophosphorus pesticides in river Rhine water at the 0.6 μg/l level using flame-ionization and mass-selective detection. No practical problems were observed during the analysis of more than 100 river water samples. 相似文献
12.
A sensitive method for the post-column reaction detection of organophosphorus pesticides is described. The method relies on photolysis of the organocompounds by irradiation with a low-pressure mercury lamp (main spectral line, 254 nm) in the presence of peroxydisulfate. The resultant orthophosphate was reacted with molybdate to form molybdophosphoric acid, which subsequently reacted with thiamine to generate thiochrome. Finally, the fluorescence intensity of thiochrome was measured at 440 nm with excitation at 375 nm. Factors affecting the rate of these reactions were optimized so that its contribution to the total band-broadening was negligible. This detection system was used for the determination of phosphate, acephate and methamidophos, which were separated on an ODS column by isocratic reversed phase chromatography with acetonitrile–water as the mobile phase. A linear relationship between analyte concentration and peak area was obtained within the range 0.016–7.0 μg ml−1 with correlation coefficients greater than 0.9995 and detection limits between 4 and 12 ng ml−1. Intra- and inter-day precision values of about 1.2% R.S.D. (n = 10) and 2.1% R.S.D. (n = 30), respectively, were obtained. Pesticide residues below ng ml−1 levels could be determined in environmental waters when a preconcentration device was coupled on-line with the HPLC system. Detection limits as low as 0.01 ng ml−1 were achieved for only 250 ml of sample. In the analyses of vegetables and grains, the detection limit was about 1 μg kg−1. 相似文献
13.
A low-temperature clean-up method for residue determination was developed and validated for 14 organophosphorus pesticides
in soybean oil, peanut oil and sesame oil by gas chromatography with flame photometric detector (GC-FPD). A different matrix
influenced the response and retention time of pesticides. Hence matrix-matched calibration standards were used to counteract
the matrix effect. The pesticide responses in blank samples of soybean oil, peanut oil and sesame oil were within the linear
range of 0.02–1 mg kg −1 and the correlation coefficients were higher than 0.9989. Average recoveries obtained from different oil samples at three
fortified levels were higher than 50% with relative standard deviations (RSDs) of less than 15%. The limit of detections (LODs)
of studied pesticides ranged from 2 to 5 μg kg −1. Thirty-nine commercial samples were analyzed, and the results were confirmed by gas chromatography–mass spectrometry (GC–MS)
in selective ion monitoring (SIM) mode. 相似文献
14.
A method for the determination of organophosphorus pesticides (diazinon, fenitrothion, fenthion, quinalphos, triazophos, phosalon and pyrazophos) in fruit (pears) and fruit juice samples was developed and validated. The samples were diluted with water, extracted by solid-phase microextraction (SPME) and analysed by gas chromatography (GC) using a flame photometric detector in phosphorous mode. Limits of detection of the method for fruit and fruit juice matrices were below 2 micrograms/kg for all pesticides. Relative standard deviations for triplicate analyses of samples fortified at 25 micrograms/kg of each pesticide were not higher than 8.7%. Recovery tests were performed for concentrations between 25 and 250 micrograms/kg. Mean recoveries for each pesticide were all above 75.9% and below 102.6% for juice, and between 70 and 99% for fruit except for pyrazophos in the fruit sample (with mean recovery of 53%). Therefore, the proposed method is applicable in the analysis of pesticides in fruit matrices and the use of the method in routine analysis of pesticide residues is discussed. 相似文献
15.
The purpose of this investigation is to develop a rapid and simple method for the assessment of organophosphorus pesticides in bovine muscle by using solid-phase extraction (SPE). After extraction with ethyl acetate (EtOAc) the homogenate is centrifuged and filtered through sodium sulfate. The fat is precipitated in methanol by cooling and the extract is diluted with water and passed through a SPE column (Isolute ENV+). After elution with EtOAc, evaporation, and redissolution, the sample is injected into a gas chromatographic (GC) capillary column DB-1701 and detected by a flame photometric detector. Recoveries from bovine muscle fortified with 12 pesticides between 4 and 65 microg/kg include three levels ranging between 59% and 109% for ten of them. The two most polar pesticides (metamidophos and acephate) are not successful. The relative standard deviations are between 1% and 10% for the ten pesticides. A simplex method is used to optimize the GC conditions. 相似文献
16.
建立了茶叶中有机磷、有机氯、拟除虫菊酯类共33种农药残留的分析方法。样品以丙酮-二氯甲烷(体积比为1:1)为提取剂经加速溶剂方法萃取,提取液用凝胶渗透色谱净化除去大部分的色素、脂类和蜡质,再用Carb-NH2小柱和Florisil小柱净化。采用气相色谱法分析、外标法定量、气相色谱-质谱法(GC-MS)定性。加标水平为0.05 mg/kg时,大部分农药的回收率为70%~120%,相对标准偏差小于20%。方法的检测限为0.005~0.05 mg/kg (以10倍信噪比计)。该方法的提取效率高,准确灵敏,目前已应用于出口茶叶中农药残留的日常检测。大量实际样品的检测结果表明,此方法适于出口茶叶中农药残留检测实际工作的需要。 相似文献
17.
Multivariate self-modeling curve resolution is applied to the quantitation of coeluted organophosphorus pesticides: fenitrothion, azinphos-ethyl, diazinon, fenthion and parathion-ethyl. Analysis of these pesticides at levels of 0.1 to 1 μg/l in the presence of natural interferences is achieved using automated on-line liquid-solid extraction (Prospekt) coupled to liquid chromatography and diode array detection followed by a recently developed multivariate self-modeling curve resolution method. The proposed approach uses only 100 ml of natural water sample and has improved resolution of the coeluted organophosphorus insecticides and their quantitation at trace level. The results have been compared with those obtained by different laboratories participating in the Aquacheck interlaboratory exercise (WRC, Medmenham, UK) where more conventional analytical techniques are being used. 相似文献
18.
A method is described for the simultaneous determination of organophosphorus and triazine pesticides in olive oil, whereby reversed-phase liquid chromatography (LC) is coupled to gas chromatography by means of an automated through-oven transfer adsorption-desorption (TOTAD) interface. The olive oil needs to be filtered only before it is loaded into the liquid chromatograph, where preseparation of the pesticide residues from the other olive oil components is carried out by using methanol-water as the eluant. The LC fraction containing the pesticides is automatically transferred to the gas chromatograph by using the TOTAD interface, which almost totally eliminates the solvent, so that water-sensitive detectors such as the nitrogen-phosphorus detector can be used. Detection limits range from 0.07 to 0.38 microg/L for organophosphorus pesticides and from 6.0 to 7.0 microg/L for triazines. The results were compared with those obtained by flame ionization detection. 相似文献
19.
The potential of an interface for the on-line coupling of microcolumn liquid chromatography (LC)and a flame photometric detector (FPD) has been further investigated. With the micro-LC/FPD system, relatively high-molecular-weight polar compounds such as cyclic adenosine monophosphate, guanosine monophos- phate, glucose monophosphate, fructose monophosphate, and phytic acid were separated and selectively detected. In order to increase the sensitivity, on-line preconcentration with a microprecolumn inserted in the rotorof a Valcovalve has been applied. Preliminary results have shown that an injection volume of at least 500 1-11 water containing organophosphorus acids at a 5–50 ng/rnl concentration level is possible. 相似文献
20.
Summary A fast and simple procedure for the analysis of aqueous samples by on-line membrane disk extraction and capillary gas chromatography (GC) is presented. As an example, organophosphorus pesticides are preconcentrated from aqueous samples on three 0.5 mm thick, 4.2 mm diameter extraction disks. The layers are dried by a stream of nitrogen (10–15 min; ambient temperature). Desorption of the analytes is carried out with ethyl acetate which is directly introduced into a retention gap under partially concurrent solvent evaporation conditions, using an early solvent vapour exit. The final analysis is carried out by GC with thermionic detection. The technique is applied to the determination of a series of organophosphorus pesticides in tap water and water from two European rivers. With a sample volume of only 2.5 ml, detection limits of 10–30 ppt are achieved in tap water and of 50–100 ppt in river water. 相似文献
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