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1.
A method is reported for the determination of atrazine, simazine, and their respective dealkylated chlorotriazine metabolites in ground, surface, and finished drinking water. Water samples are diluted 1:4 in an injection vial prior to analysis using liquid chromatography/electrospray ionization-mass spectrometry/mass spectrometry (LC/ESI-MS/MS). The lower limit of method validation is 0.10 microg/L (ppb) for 2-chloro-4-(ethylamino)-6-isopropylamino)-s-triazine (atrazine, G-30027), 2-chloro-4, 6-(diethylamino)-s-triazine (simazine, G-27692), 2-amino-4-chloro-6-(isopropylamino)-s-triazine (deethylatrazine, DEA, or G-30033), 2-amino-4-chloro-6-(ethylamino)-s-triazine (deisopropylatrazine, DIA, or G-28279), and 2,4-diamino-6-chloro-s-triazine (didealkylatrazine, DDA, or G-28273). The overall mean procedural recoveries (and % relative standard deviations) for atrazine, simazine, DEA, DIA, and DDA are 98 (4.4), 102 (3.6), 99 (4.8), 103 (4.0), and 109% (4.8%), respectively, in finished drinking water; 108 (2.7), 104 (5.4), 113 (4.5), 111 (5.2), and 105% (5.3%), respectively, in groundwater; and 96 (6.9), 103 (4.2), 102 (4.4), 102 (5.2), and 102% (8.2%), respectively, in surface water. The method validation was conducted under U.S. EPA FIFRA Good Laboratory Practice Guidelines 40 CFR 160.  相似文献   

2.
An enantioselective method for the separation and quantification of the diastereomer pairs of metolachlor and S-metolachlor in surface and ground waters is presented. Samples are purified and concentrated using a C18 (octadecyl silica) solid-phase extraction (SPE) procedure and analyzed by chiral column liquid chromatography-mass spectrometry/mass spectrometry (LC/MS/MS) interfaced with either atmospheric pressure chemical ionization (APcI) or atmospheric pressure photoionization (APPI) sources. The overall mean percent procedural recoveries (percent relative standard deviations) are 89% (10.6%) for surface water and 80% (9.1%) for ground water. The method limit of quantitation (LOQ) is 0.10 ppb. The method validation was conducted under U.S. EPA FIFRA Good Laboratory Practice Guidelines 40 CFR 160.  相似文献   

3.
Rugged LC-MS/MS survey analysis for acrylamide in foods   总被引：8，自引：0，他引：8  
The described liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the detection of acrylamide in food entails aqueous room temperature extraction, SPE cleanup, and analysis by LC-MS/MS. The method is applicable to a wide variety of foods. [(13)C(3)]acrylamide is the internal standard. The limit of quantitation is 10 ppb (microg/kg). Data were obtained in duplicate from >450 products representing >35 different food types. The variability in analyte levels in certain food types suggests that it may be possible to reduce acrylamide levels in those foods.  相似文献   

4.
A method is reported for the determination of atrazine and its dealkylated chlorotriazine metabolites in ground, surface, and deionized water. Water samples are adjusted to pH 3-4 prior to loading onto two SPE cartridges in series: C-18 and C-18/cation exchange mixed-mode polymeric phases. The analytes are eluted from each of the two cartridges separately, and the pooled and concentrated fraction is analyzed using gas chromatography-mass selective detection in the selected ion monitoring mode. The lower limit of method validation is 0.10 micrograms/L (ppb) for 2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine (atrazine), 2-amino-4-chloro-6-(isopropylamino)-s-triazine (G-30033, deethylatrazine), 2-amino-4-chloro-6-(ethylamino)-s-triazine (G-28279, deisopropylatrazine), and 2,4-diamino-6-chloro-s-triazine (G-28273, didealkyatrazine). The overall mean procedural recoveries (and standard deviations) are 96 (6.9), 96 (5.5), 95 (6.8), and 100% (10%) for atrazine, G-30033, G-28279, and G-28273, respectively (n = 49). The method validation study was conducted under U.S. EPA FIFRA Good Laboratory Practice Guidelines 40 CFR 160. The reported procedure accounts for residues of G-28273 in water.  相似文献   

5.
LC/MS analysis of cyclohexanedione oxime herbicides in water   总被引：1，自引：0，他引：1  
A multiresidue method for the determination of alloxydim (methyl 2, 2-dimethyl-4, 6-dioxo-5-[1-[2-propenyloxy)amino]butylidene]cyclohexanec arb oxylate), clethodim (E, E)-(+/-)-2-[1-[[3-chloro-2-propenyl)oxy]imino]propyl]-5-[2-(ethylthio )propyl]-3-hydroxy-2-cyclohexen-1-one), sethoxydim ((+/-)-2-[1-(ethoxyimino)butyl]-5-[2-ethylthio)propyl]-3-hydroxy-2 -cy clohexen-1-one), and two metabolites, clethodim sulfoxide ((E, E)-(+/-)-2-[1-[[3-chloro-2-propenyl)oxy]imino]propyl]-5-[2-(ethylsulf inyl)propyl]-3-hydroxy-2-cyclohexen-1-one) and sethoxydim sulfoxide ((+/-)-2-[1-(ethoxyimino)butyl]-5-[2-ethylsulfinyl)propyl]-3 -hydroxy- 2-cyclohexen-1-one), in water by high-performance liquid chromatography/electrospray/mass spectrometry (LC/ES/MS) is reported. River water and distilled water were spiked at 0.08 and 0.8 microgram L(-1) with all three herbicides, which were then extracted from the water by C(18)-SPE (SPE = solid-phase extraction). The herbicides and metabolites were quantified and confirmed using selected ion monitoring. The percent recoveries of the herbicides from water spiked at 0.8 microgram L(-1) were as follows: alloxydim, 117 +/- 11%; clethodim, 96 +/- 14%; sethoxydim, 89 +/- 13%. There was no evidence of oxidation of clethodim and sethoxydim during the extraction to their respective sulfoxides. The limit of quantitation was <0.1 microgram L(-1). We have shown that we can analyze and confirm three cyclohexanedione oxime herbicides and two metabolites in water by LC/ES/MS. This multiresidue method should also be appropriate for other cyclohexanedione oximes.  相似文献   

6.
A gas chromatographic/mass spectrometric method capable of confirming phorate, terbufos, their sulfoxides, and sulfones in water is reported. Parents and their metabolites are separated in less than 5 min using a short capillary GC column and high carrier gas linear velocities. Positive ion chemical ionization mass spectrometry generates (M + H) ions indicative of the different molecular weights of the analytes and at least one confirmatory fragment ion for each analyte. Residues have been qualitatively confirmed at the 1 ppb level in fortified water samples from a variety of sources. Apparent residues in control water were less than 0.1 ppb.  相似文献   

7.
A method was developed for detection of a variety of polar drug residues in eggs via liquid chromatography/tandem mass spectrometry (LC/MS/MS) with electrospray ionization (ESI). A total of twenty-nine target analytes from four drug classes-sulfonamides, tetracyclines, fluoroquinolones, and beta-lactams-were extracted from eggs using a hydrophilic-lipophilic balance polymer solid-phase extraction (SPE) cartridge. The extraction technique was developed for use at a target concentration of 100 ng/mL (ppb), and it was applied to eggs containing incurred residues from dosed laying hens. The ESI source was tuned using a single, generic set of tuning parameters, and analytes were separated with a phenyl-bonded silica cartridge column using an LC gradient. In a related study, residues of beta-lactam drugs were not found by LC/MS/MS in eggs from hens dosed orally with beta-lactam drugs. LC/MS/MS performance was evaluated on two generations of ion trap mass spectrometers, and key operational parameters were identified for each instrument. The ion trap acquisition methods could be set up for screening (a single product ion) or confirmation (multiple product ions). The lower limit of detection for screening purposes was 10-50 ppb (sulfonamides), 10-20 ppb (fluoroquinolones), and 10-50 ppb (tetracyclines), depending on the drug, instrument, and acquisition method. Development of this method demonstrates the feasibility of generic SPE, LC, and MS conditions for multiclass LC/MS residue screening.  相似文献   

8.
A new rapid and sensitive method has been developed, using liquid chromatography in tandem mass spectrometry (LC-ESI-MS/MS) to identify green tea catechin metabolites in plasma and urine after oral intake of a green tea extract. (-)-Epigallocatechin-3-gallate (EGCG), (-)-epicatechin-3-gallate (ECG), (-)-epigallocatechin (EGC)-glucuronide, (-)-epicatechin (EC)-glucuronide, and EC-sulfate were identified in plasma, whereas in urine only the conjugated catechins were detected (EGC-glucuronide, EGC-sulfate, EC-glucuronide, and EC-sulfate). Standard calibration curves prepared in plasma were found to be linear in the range of 10.9-1379.3 nmol/L for EGCG, EGC, ECG, and EC. The accuracy and precision of this assay showed a coefficient of variation of <15%. The method allowed the detection and quantification limits (for 20 microL injection) from 1.1 to 2.6 nmol/L and 3.8-8.7 nmol/L, respectively, in plasma and 0.8-1.8 nmol/L and 2.6-6.0 nmol/L, respectively, in urine. This method can be applied for future clinical and epidemiological studies, allowing the identification of the active metabolites that will reach the target tissues.  相似文献   

9.
The carcinogen acrylamide (AA) is formed during the processing of food. AA is metabolized to mercapturic acids, which are excreted with urine. A hydrophilic interaction liquid chromatography tandem mass spectrometry method (HILIC-MS/MS) using a zwitterionic stationary phase (Zic-HILIC) was developed and validated to quantitate the mercapturic acids of AA (AAMA) and glycidamide (GAMA), and AAMA-sulfoxide in human urine. In contrast to reversed phases, the application of Zic-HILIC resulted in efficient retention and separation of these highly polar compounds. Off-line sample workup was avoided by application of column switching with a Stability BS-C17 trap column prior to the analytical column, thus minimizing interferences with the urinary matrix. Limit of quantification values (LOQs) were 0.5 microg/L (AAMA), 2.0 microg/L (AAMA-sulfoxide), and 1.0 microg/L (GAMA) in human urine. Median concentrations in urine samples ( n = 54) of six nonsmoking human subjects were 24.0 microg/L (AAMA, 7.8-79.8 microg/L), 16.7 microg/L (AAMA-sulfoxide, 6.8-70.1 microg/L), and 3.82 microg/L (GAMA, 1.0-23.6 microg/L).  相似文献   

10.
Sulfamethazine (SMT) and its major metabolite, N(4)-acetylsulfamethazine (NA-SMT), were each recovered from spiked water (0.1 ppb) and 10% (w/v) aqueous suspensions of soil (1 ppb) or composted manure (1 ppb), by using a three-stage solid phase immunoextraction (SPIE) system, followed by detection with matrix-assisted laser/desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS). Sulfonamide recovery rates are reported for separate stages of the SPIE system and for trace-level sulfonamide SPIE extraction from the environmental samples. SPIE MALDI-TOF MS is a rapid and definitive technique with potentially better efficiency relative to other established trace-level sulfonamide analytical methods. SPIE MALDI-TOF MS required 1.5 h per batch (8-24 samples/batch) for sample enrichment, 5 min per batch for probe preparation, and 5 min per sample to acquire and process the spectrum. This is the first time MALDI-TOF MS has been reported as a potential means of detecting trace-level drug residues in complex environmental samples.  相似文献   

11.
A method making use of turbulent flow chromatography automated online extraction with tandem mass spectrometry (MS/MS) was developed for the analysis of 4 quinolones and 12 fluoroquinolones in honey. The manual sample preparation was limited to a simple dilution of the honey test portion in water followed by a filtration. The extract was online purified on a large particle size extraction column where the sample matrix was washed away while the analytes were retained. Subsequently, the analytes were eluted from the extraction column onto an analytical column by means of an organic solvent prior to chromatographic separation and MS detection. Validation was performed at three fortification levels (i.e., 5, 20, and 50 microg/kg) in three different honeys (acacia, multiflower, and forest) using the single-point calibration procedure by means of either a 10 or 25 microg/kg calibrant. Good recovery (85-127%, median 101%) as well as within-day (2-18%, median 6%) and between-day (2-42%, median 9%) precision values was obtained whatever the level of fortification and the analyte surveyed. Due to the complexity of the honey matrix and the large variation of the MS/MS transition reaction signals, which were honey-dependent, the limit of quantification for all compounds was arbitrarily set at the lowest fortification level considered during the validation, e.g., 5 microg/kg. This method has been successfully applied in a minisurvey of 34 honeys, showing ciprofloxacin and norfloxacin as the main (fluoro)quinolone antibiotics administered to treat bacterial diseases of bees. Turbulent flow chromatography coupled to LC-MS/MS showed a strong potential as an alternative method compared to those making use of offline sample preparation, in terms of both increasing the analysis throughput and obtaining higher reproducibility linked to automation to ensure the absence of contaminants in honey samples.  相似文献   

12.
A method developed for the determination of ethylene dibromide in table-ready foods has been modified and expanded to include 7 other volatile halocarbons and carbon disulfide. Samples are stirred with water and purged with nitrogen for 0.5 h in a water bath at 100 degrees C. The analytes collected on a duplex trap composed of Tenax TA and XAD-4 resin are eluted with hexane and determined by gas chromatography with electron capture detection or Hall electrolytic conductivity detection. Flame photometric detection in the sulfur mode is used to determine carbon disulfide. Thick-film, wide-bore capillary columns are used exclusively in both the determination and confirmation of the halogenated analytes. The higher levels of analytes are also confirmed by full scan gas chromatography mass spectrometry (GC/MS). Samples are analyzed for carbon disulfide, methylene chloride, chloroform, 1,2-dichloroethane, methyl chloroform, carbon tetrachloride, trichloroethylene, 1,2-dibromoethane, and tetrachloroethylene. Initially, 19 table-ready foods from the Food and Drug Administration's Total Diet Study were analyzed by this method. A limited survey of those food items exhibiting high levels of analytes was conducted. Samples exhibited levels up to 3300 ppb (methyl chloroform in Parmesan cheese). Recoveries of all 9 analytes from fortified samples ranged from 83 to 104%. Chromatograms from this purge and trap method are clean, enabling quantitation levels of low parts per billion and sub-parts per billion to be achieved for the halogenated analytes. The quantitation limit for carbon disulfide is 12 ppb. Two compounds found in drinking water were identified by GC/MS as bromodichloromethane and chlorodibromomethane. Drinking water from several cities was analyzed for these trihalomethanes as well as for bromoform. Levels of up to 17 ppb bromodichloromethane were found. Recoveries ranged from 96 to 103%.  相似文献   

13.
A multiresidue method was developed for the simultaneous determination of low parts per billion (ppb) concentrations of the herbicides alachlor, metolachlor, atrazine, and simazine in water and soil using isotope dilution gas chromatography/mass spectrometry (GC/MS). Known amounts of 15N,13C-alachlor and 2H5-atrazine were added to each sample as internal standards. The samples were then prepared by a solid phase extraction with no further cleanup. A high resolution GC/low resolution MS system with data acquisition in selected ion monitoring mode was used to quantitate herbicides in the extract. The limit of detection was 0.05 ppb for water and 0.5 ppb for soil. Accuracy greater than 80% and precision better than 4% was demonstrated with spiked samples.  相似文献   

14.
A method was developed for the determination and confirmation of furazolidone, nitrofurazone, furaltadone, and nitrofurantoin as their side-chain residues in honey using liquid chromatography-tandem mass spectrometry (LC-MS/MS). An initial solid-phase extraction cleanup of the honey samples was followed by overnight hydrolysis and derivatization of the nitrofuran side-chain residues with 2-nitrobenzaldehyde. After pH adjustment and liquid-liquid extraction, the extracts were assayed by LC-MS/MS using electrospray ionization in the positive ion mode. The method was validated at concentrations ranging from 0.5 to 2.0 ppb with accuracies of 92-103% and coefficients of variation of < or =10%. The lowest calibration standard used (0.25 ppb) was defined as the limit of quantitation for all four nitrofuran side-chain residues. The extracts and standards were also used for confirmatory purposes. Honey from dosed beehives was assayed to study the stability of the nitrofuran residues and to demonstrate the effectiveness of the method.  相似文献   

15.
A multiresidue method is reported for the determination of atrazine and its dealkylated chlorotriazine metabolites in water. Water samples are buffered to pH 10 and partitioned in ethyl acetate. Final analysis is accomplished using gas chromatography/mass selective detection (GC/MSD) in the selected ion monitoring (SIM) mode. The limit of detection (LOD) is 0.050 ng and the limit of quantification (LOQ) is 0.10 ppb for 2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine (atrazine), 2-amino-4-chloro-6-(isopropylamino)-s-triazine (G-30033), 2-amino-4-chloro-6-(ethylamino)-s-triazine (G-28279), and 2, 4-diamino-6-chloro-s-triazine (G-28273). The mean procedural recoveries were 90, 92, 98, and 85% and the standard deviations were 12, 13, 16, and 20% for atrazine, G-30033, G-28279, and G-28273, respectively (n = 30). The study was conducted under U.S. EPA FIFRA Good Laboratory Practice Guidelines 40 CFR 160 for method validation. The reported procedure accounts for residues of G-28273 in water that are not included in EPA Method 507.  相似文献   

16.
A sensitive method is described for the determination and confirmation of zeranol and zearalenone, as well as their isomers and metabolites, in edible animal tissue. The analytes are extracted from tissue with methanol, hydrolyzed enzymatically, cleaned up by acid-base partitioning, determined by liquid chromatography (LC) with electrochemical (EC) detection, and confirmed by gas chromatography/mass spectrometry (GC/MS). LC analysis is performed by isocratic elution with a buffered mobile phase using a Nova-Pak reverse-phase C18 column with amperometric EC detection at +0.90 V. Capillary GC/MS analysis of the trimethylsilyl derivatives provides mass spectral confirmations.  相似文献   

17.
Orysastrobin is a new strobilurin-type fungicide to control leaf and panicle blast and sheath blight in rice. An analytical method was developed to determine the residues of orysastrobin and its two isomers, the main metabolite F001 and the major impurity F033, in hulled rice by the use of high-performance liquid chromatography with ultraviolet photometry (HPLC-UV) and liquid chromatography with tandem mass spectrometry (LC-MS/MS). All compounds were extracted with acetone from hulled rice samples. The extract was diluted with saline water, and an extraction step using dichloromethane/n-hexane partition was used to recover analytes from the aqueous phase. An n-hexane/acetonitrile partition and Florisil column chromatography were employed to further remove interfering coextractives prior to instrumental analysis. An octadecylsilyl column was successfully applied to identify orysastrobin and its isomers in sample extracts. Net recovery rates of orysastrobin, F001, and F033 from fortified samples ranged from 80.6 to 114.8% using HPLC-UV and LC-MS/MS. Relative standard deviations for the analytical methods were all <20%, and the quantification limits of the method were in the 0.002-0.02 mg/kg range. The proposed methods were reproducible and sufficiently accurate to evaluate the terminal residue of orysastrobin and its isomers in rice.  相似文献   

18.
The carcinogenic compound ptaquiloside is produced by bracken fern (Pteridium aquilinum L.). Ptaquiloside can enter the soil matrix and potentially leach to the aquatic environment, and methods for characterizing ptaquiloside content and fate in soil and groundwater are needed. A sensitive detection method has been developed using liquid chromatography-tandem mass spectrometry (LC-MS/MS) for analyzing ptaquiloside and its transformation product pterosin B. Detection limits are 0.19 microg/L (ptaquiloside) and 0.15 microg/L (pterosin B), which are 300-650 times better than previously published LC-UV methods. Sequential soil extractions are made using 5 mM ammonium acetate for extraction of ptaquiloside, followed by 80% methanol extraction for pterosin B. Groundwater samples are cleaned-up and preconcentrated by a factor of 20 using solid-phase extraction. The LC-MS/MS method enables quantification of ptaquiloside and pterosin B in soil and groundwater samples at environmentally relevant concentrations and delivers a reliable identification because of the structure-specific detection method.  相似文献   

19.
A new methodology is described for rapidly determining the herbicide oryzalin in water, citrus fruits, and stone fruits by liquid chromatography with negative ion electrospray ionization tandem mass spectrometry (LC/MS/MS). Oryzalin is extracted from water using a polymeric sorbent solid phase extraction (SPE) column and from fruit using methanol. The water samples require no further purification, but an aliquot of the fruit sample extracts is diluted with water and purified using a polymeric 96 well SPE plate. Purified extracts are concentrated prior to determination by LC/MS/MS at m/z 345 (Q1) and m/z 281 (Q3) using an external standard for calibration. The validated limits of quantitation were 0.05 microg/L in water (drinking water, surface water, and groundwater) and 0.01 microg/g in citrus fruits (oranges and lemons) and stone fruits (peaches and cherries). Recoveries averaged 102% for water samples and 85-89% for the various types of fruit samples. For all fortification levels combined, the relative standard deviations ranged from 4 to 6% for water and from 2 to 4% for fruit.  相似文献   

20.
Maximum residue limits (MRLs) have been established by the European Union when tylosin is used therapeutically. They are fixed at 200 microg/kg for eggs. A highly sensitive and selective quantitative liquid chromatography electrospray ionization tandem mass spectrometry (LC/ESI/MS/MS) method suitable for monitoring tylosin residues in eggs to determine its depletion kinetics was developed and validated. For sample pretreatment all samples were liquid-liquid extracted with citrate buffer (pH 5.0) and acetonitrile. Liquid chromatographic separation was carried out on a reversed phase C18 column employing a 0.5% formic acid/acetonitrile gradient system. The tylosin recovery in eggs at a concentration range from 1.0-400 microg/kg was >82% with relative standard deviations between 1.5 and 11.0%. In two experimental studies administrating tylosin via feed (final dosage: 1.5 g/kg) or drinking water (final dosage: 0.5 g/L), no residues above the MRL were found during and after treatment. Moreover, all samples were well below the actual MRL of 200 microg/kg. Therefore, our residue data suggest that a withholding period for eggs is not required when laying hens are treated with tylosin in recommended dosages via feed or drinking water. Keywords: Tylosin; residue; depletion; laying hen; withholding period; mass spectrometry.  相似文献   

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