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1.
C. R. Dockery A. R. Stefan A. A. Nieuwland S. N. Roberson B. M. Baguley J. E. Hendrix S. L. Morgan 《Analytical and bioanalytical chemistry》2009,394(8):2095-2103
Systematic designed experiments were employed to find the optimum conditions for extraction of direct, reactive, and vat dyes
from cotton fibers prior to forensic characterization. Automated microextractions were coupled with measurements of extraction
efficiencies on a microplate reader UV–visible spectrophotometer to enable rapid screening of extraction efficiency as a function
of solvent composition. Solvent extraction conditions were also developed to be compatible with subsequent forensic characterization
of extracted dyes by capillary electrophoresis with UV–visible diode array detection. The capillary electrophoresis electrolyte
successfully used in this work consists of 5 mM ammonium acetate in 40:60 acetonitrile–water at pH 9.3, with the addition
of sodium dithionite reducing agent to facilitate analysis of vat dyes. The ultimate goal of these research efforts is enhanced
discrimination of trace fiber evidence by analysis of extracted dyes.
Figure Fitted absorbance response surface for extraction of a direct dye, C. I. yellow 58, using a ternary solvent system. 相似文献
2.
Amy R. Stefan Christopher R. Dockery Alexander A. Nieuwland Samantha N. Roberson Brittany M. Baguley James E. Hendrix Stephen L. Morgan 《Analytical and bioanalytical chemistry》2009,394(8):2077-2085
The extraction and separation of dyes present on textile fibers offers the possibility of enhanced discrimination between
forensic trace fiber evidence. An automated liquid sample handling workstation was programmed to deliver varying solvent combinations
to acid-dyed nylon samples, and the resulting extracts were analyzed by an ultraviolet/visible microplate reader to evaluate
extraction efficiencies at different experimental conditions. Combinatorial experiments using three-component mixture designs
varied three solvents (water, pyridine, and aqueous ammonia) and were employed at different extraction temperatures for various
extraction durations. The extraction efficiency as a function of the three solvents (pyridine/ammonia/water) was modeled and
used to define optimum conditions for the extraction of three subclasses of acid dyes (anthraquinone, azo, and metal complex)
from nylon fibers. The capillary electrophoresis analysis of acid dye extracts is demonstrated using an electrolyte solution
of 15 mM ammonium acetate in acetonitrile/water (40:60, v/v) at pH 9.3. Excellent separations and discriminating diode array spectra are obtained even for dyes of similar color.
Figure Capillary electropherogram of three acid dyes extracted from nylon 6,6 thread 相似文献
3.
Eight textile dye compounds including five cationic dyes, namely, basic blue 41, basic blue 9, basic green 4, basic violet 16 and basic violet 3, and three anionic dyes, acid green 25, acid red 1 and acid blue 324, were separated and detected by non-aqueous capillary electrophoresis (NACE) with electrochemical detection. Simultaneous separations of acid and basic dyes were performed using an acetonitrile-based buffer. Particular attention was paid to the determination of basic textile dyes. The optimized electrophoresis buffer for the separation of basic dyes was a solvent mixture of acetonitrile/methanol (75:25, v/v) containing 1 M acetic acid and 10 mM sodium acetate. The limits of detection for the basic dyes were in the range of 0.1–0.7 μg mL−1. An appropriate solid-phase extraction procedure was developed for the pre-treatment of aqueous samples with different matrices. This analytical approach was successfully applied to various water samples including river and lake water which were spiked with textile dyes. 相似文献
4.
Dispersive liquid—liquid microextraction coupled with high-performance liquid chromatography—diode-array detection was applied
for the extraction and determination of 11 priority pollutant phenols in wastewater samples. The analytes were extracted from
a 5-mL sample solution using a mixture of carbon disulfide as the extraction solvent and acetone as the dispersive solvent.
After extraction, solvent exchange was carried out by evaporating the solvent and then reconstituting the residue in a mixture
of methanol–water (30:70). The influences of different experimental dispersive liquid—liquid microextraction parameters such
as extraction solvent type, dispersive solvent type, extraction and dispersive solvent volume, salt addition, and pH were
studied. Under optimal conditions, namely pH 2, 165-μL extraction solvent volume, 2.50-mL dispersive solvent volume, and no
salt addition, enrichment factors and limits of detection ranged over 30–373 and 0.01–1.3 μg/L, respectively. The relative
standard deviation for spiked wastewater samples at 10 μg/L of each phenol ranged between 4.3 and 19.3% (n = 5). The relative recovery for wastewater samples at a spiked level of 10 μg/L varied from 65.5 to 108.3%. 相似文献
5.
Miklautz H Keller D Lopez Holguin F Woloszczak R 《Analytical and bioanalytical chemistry》2006,384(5):1191-1195
An automated spectrophotometric method based on an HPLC system with a diode array detector was used to determine the pK
a values of compounds with low water solubility in a universal buffer containing acetonitrile as cosolvent. The column of the
system was replaced with a capillary connecting the injection system and the diode array detector. Specific solvent effects
were corrected for using the dielectric constants of the mixed solvent and pure water. The method was tested using 4-hydroxybenzoic
acid and the results were compared with those obtained with a spectrophotometer. Linear regression lines with different slopes
were obtained from spectrophotometric measurements of different cosolvent–water mixtures. These effects were shown to depend
upon the polarity of the solventwater mixture, and they were explained by the solvatochromic behavior of the 4-hydroxybenzoic
acid in the solvent–water mixture. 相似文献
6.
A simple method for determination of rare earth elements (REEs) by liquid–liquid–liquid microextraction (LLLME) coupled with capillary electrophoresis and ultraviolet technique was developed. In the LLLME system, 40 mmol L?1 4-benzoyl-3-methy-1-phenyl-5-pyrazolinone (PMBP) acted as extractant and 4% (v/v) formic acid was used as back-extraction solution. The parameters influencing the LLLME, including the type of the organic solvent, sample pH, formic acid concentration, PMBP concentration, extraction time, volume of organic solvent, stirring rate and phase volume ratio, were investigated. Under the optimized conditions, the detection limits (S/N = 3) of REEs were in the range of 0.19–0.70 ng mL?1. The developed method was successfully applied to the determination of trace amounts of REEs in water samples. 相似文献
7.
P. Hashemi M. M. Abolghasemi A. R. Fakhari S. N. Ebrahimi S. Ahmadi 《Chromatographia》2007,66(3-4):283-286
A new, simple hydrodistillation–solvent microextraction (HD–SME) technique has been used for analysis of the volatile components
of the aerial parts of Artemisia aucheri. The components were collected in a single microdrop, and this was injected directly for gas chromatographic–mass spectrometric
(GC–MS) analysis. The effects on extraction efficiency of extraction solvent, sample mass, microdrop volume, and extraction
time were optimized by use of a simplex method. The identities of the components of HD–SME extracts were confirmed according
to their retention indexes and mass spectra with those of standards. Forty components were extracted and identified by use
of the method; 1,8-cineol (22.8%), chrysanthenone (18.16%), α-pinene (8.33%), and mesitylene (7.41%) were the major constituents.
The results obtained from the microextraction method were compared with those obtained by conventional hydrodistillation. 相似文献
8.
Saraji M Khalili Boroujeni M Hajialiakbari Bidgoli AA 《Analytical and bioanalytical chemistry》2011,400(7):2149-2158
Dispersive liquid–liquid microextraction (DLLME) and hollow fiber liquid–liquid–liquid microextraction (HF-LLLME) combined
with HPLC–DAD have been applied for the determination of three narcotic drugs (alfentanil, fentanyl, and sufentanil) in biological
samples (human plasma and urine). Different DLLME parameters influencing the extraction efficiency such as type and volume
of the extraction solvent and the disperser solvent, concentration of NaOH, and salt addition were investigated. In the HF-LLLME,
the effects of important parameters including organic solvent type, concentration of NaOH as donor solution, concentration
of H2SO4 as acceptor phase, salt addition, stirring rate, temperature, and extraction time were investigated and optimized. The results
showed that both extraction methods exhibited good linearity, precision, enrichment factor, and detection limit. Under optimal
condition, the limits of detection ranged from 0.4 to 1.9 μg/L and from 1.1 to 2.3 μg/L for DLLME and HF-LLLME, respectively.
For DLLME, the intra- and inter-day precisions were 1.7–6.4% and 14.2–15.9%, respectively; and for HF-LLLME were 0.7–5.2%
and 3.3–10.1%, respectively. The enrichment factors were from 275 to 325 and 190 to 237 for DLLME and HF-LLLME, respectively.
The applicability of the proposed methods was investigated by analyzing biological samples. For analysis of human plasma and
urine samples, HF-LLLME showed higher precision, more effective sample clean-up, higher extraction efficiency, lower organic
solvent consumption than DLLME. 相似文献
9.
Mohammad Saraji Ali Akbar Hajialiakbari Bidgoli 《Analytical and bioanalytical chemistry》2010,397(7):3107-3115
A novel and efficient surfactant-assisted dispersive liquid–liquid microextraction combined with high-performance liquid chromatography–photodiode
array detection was developed for the determination of phenylurea herbicides in water samples. Based on this procedure, which
is a dispersive-solvent-free technique, the extractant is dispersed in the aqueous sample using methyltrialkylammonium chloride.
Compared with the conventional dispersive liquid–liquid microextraction, the new extraction method has many advantages such
as higher extraction efficiency, low cost, reduced environmental hazards, and consumption of less extracting solvent. A few
microliters of chloroform containing an appropriate amount of methyltrialkylammonium chloride (mixture of C8–C10) was used
to extract the analytes from water samples. The main parameters relevant to the extraction process (namely, type of surfactant,
selection of extractant solvent, extractant volume, surfactant concentration, ionic strength, and extraction time) were investigated.
The performed analytical procedure showed limits of detection ranging from 2.3 to 18 ng/L, and precision ranges from 0.6%
to 2.0% (as intra-day relative standard deviation, RSD) and from 1.3% to 8.3% (as inter-day RSD) depending on the analyte.
The method showed good linearity between 0.04 and 40 μg/L with squared correlation coefficients better than 0.9920. This newly
established approach was successfully applied to spiked real water samples. 相似文献
10.
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
11.
Ru-Song Zhao Xia Wang Jing Sun Shan-Shan Wang Jin-Peng Yuan Xi-Kui Wang 《Analytical and bioanalytical chemistry》2010,397(4):1627-1633
A novel and environmentally friendly microextraction method, termed ionic liquid dispersive liquid-phase microextraction (IL-DLPME),
has been developed for rapid enrichment of triclosan and triclocarban before analysis by high-performance liquid phase chromatography–electrospray
tandem mass spectrometry (HPLC–ESI-MS–MS). Instead of using toxic organic solvents, an ionic liquid was used as a green extraction
solvent. This also avoided the instability of the suspending drop in single-drop liquid-phase microextraction, and the heating
and cooling step in temperature-controlled ionic liquid dispersive liquid phase microextraction. Factors that may affect the
enrichment efficiency, for example volume of ionic liquid, type and volume of dispersive solvent, pH, extraction time, and
NaCl content were investigated in detail and optimized. Under optimum conditions, linearity of the method was observed over
the range 0.2–12 μg L−1 for triclocarban and 1–60 μg L−1 for triclosan with correlation coefficients ranging from 0.9980 to 0.9990, respectively. The sensitivity of the proposed
method was found to be excellent, with limits of detection in the range 0.040–0.58 μg L−1 and precision in the range 7.0–8.8% (RSD, n = 5). This method has been successfully used to analyze real environmental water samples and satisfactory results were achieved.
Average recoveries of spiked compounds were in the range 70.0–103.5%. All these results indicated that the developed method
would be a green method for rapid determination of triclosan and triclocarban at trace levels in environmental water samples. 相似文献
12.
Santi Tungprapa Tanarinthorn Puangparn Monchawan Weerasombut Ittipol Jangchud Porntiva Fakum Somsak Semongkhol Chidchanok Meechaisue Pitt Supaphol 《Cellulose (London, England)》2007,14(6):563-575
This paper reports an investigation of the effects of solvent system, solution concentration, and applied electrostatic field
strength (EFS) on the morphological appearance and/or size of as-spun cellulose acetate (CA) products. The single-solvent
systems were acetone, chloroform, N,N
-dimethylformamide (DMF), dichloromethane (DCM), methanol (MeOH), formic acid, and pyridine. The mixed-solvent systems were
acetone–DMAc, chloroform–MeOH, and DCM–MeOH. Chloroform, DMF, DCM, MeOH, formic acid, and pyridine were able to dissolve CA,
forming clear solutions (at 5% w/v), but electrospinning of these solutions produced mainly discrete beads. In contrast, electrospinning of the solution of
CA in acetone produced short and beaded fibers. At the same solution concentration of 5% (w/v) electrospinning of the CA solutions was improved by addition of MeOH to either chloroform or DCM. For all the solvent systems
investigated smooth fibers were obtained from 16% (w/v) CA solutions in 1:1, 2:1, and 3:1 (v/v) acetone–DMAc, 14–20% (w/v) CA solutions in 2:1 (v/v) acetone–DMAc, and 8–12% (w/v) CA solutions in 4:1 (v/v) DCM–MeOH. For the as-spun fibers from CA solutions in acetone–DMAc the average diameter ranged between 0.14 and 0.37 μm
whereas for the fibers from solutions in DCM–MeOH it ranged between 0.48 and 1.58 μm. After submersion in distilled water
for 24 h the as-spun CA fibers swelled appreciably (i.e. from 620 to 1110%) but the physical integrity of the fibrous structure
remained intact. 相似文献
13.
Directly suspended droplet liquid–liquid–liquid microextraction (LLLME) has been used to determine residues of diclofenac
(2-[2-(2,6-dichlorophenyl) aminophenyl] ethanoic acid), in environmental water samples. In this technique a free suspended
droplet of an aqueous solvent is delivered to the top-center position of an immiscible organic solvent floating on the top
of an aqueous sample while being agitated by a stirring bar placed on the bottom of the sample cell. Recently, diclofenac
was found as an environmental contaminant in sewage, surface, ground and drinking water samples. In the present work, diclofenac
was extracted from water samples by LLLME and analysed by HPLC with UV detection at 281 nm. Factors such as organic solvent,
extraction and back extraction times, stirring rate and the pH of acceptor and donor phases were optimized. Enrichment factor
and detection limit (LOD, n = 7) were 102 and 0.1 μg L−1, respectively. The linearity ranged from 0.5 to 2,000 μg−1 with a %RSD (n = 5) of 7.2 at S/N = 3. All experiments were carried out at room temperature (22 ± 0.5 °C). 相似文献
14.
Zhao RS Yuan JP Li HF Wang X Jiang T Lin JM 《Analytical and bioanalytical chemistry》2007,387(8):2911-2915
Hollow-fiber liquid-phase microextraction (HF-LPME), a relatively new sample preparation technique, has attracted much interest
in the field of environmental analysis. In the current study, a novel method based on hollow-fiber liquid-phase microextraction
with in situ derivatization and gas chromatography–mass spectrometry for the measurement of triclosan in aqueous samples is
described. Hollow-fiber liquid-phase microextraction conditions such as the type of extraction solvent, the stirring rate,
the volume of derivatizing reagent, and the extraction time were investigated. When the conditions had been optimized, the
linear range was found to be 0.05–100 μg l−1 for triclosan, and the limit of detection to be 0.02 μg l−1. Tap water and surface water samples collected from our laboratory and Wohushan reservoir, respectively, were successfully
analyzed using the proposed method. The recoveries from the spiked water samples were 83.6 and 114.1%, respectively; and the
relative standard deviation (RSD) at the 1.0 μg l−1 level was 6.9%. 相似文献
15.
A novel microextraction method is introduced based on dispersive liquid–liquid microextraction (DLLME) in which an in situ
metathesis reaction forms a water-immiscible ionic liquid (IL) that preconcentrates aromatic compounds from water followed
by separation using high-performance liquid chromatography. The simultaneous extraction and metathesis reaction forming the
IL-based extraction phase greatly decreases the extraction time as well as provides higher enrichment factors compared to
traditional IL DLLME and direct immersion single-drop microextraction methods. The effects of various experimental parameters
including type of extraction solvent, extraction and centrifugation times, volume of the sample solution, extraction IL and
exchanging reagent, and addition of organic solvent and salt were investigated and optimized for the extraction of 13 aromatic
compounds. The limits of detection for seven polycyclic aromatic hydrocarbons varied from 0.02 to 0.3 μg L−1. The method reproducibility produced relative standard deviation values ranging from 3.7% to 6.9%. Four real water samples
including tap water, well water, creek water, and river water were analyzed and yielded recoveries ranging from 84% to 115%.
相似文献
16.
Pragst F 《Analytical and bioanalytical chemistry》2007,388(7):1393-1414
Solid-phase microextraction (SPME) is a miniaturized and solvent-free sample preparation technique for chromatographic–spectrometric
analysis by which the analytes are extracted from a gaseous or liquid sample by absorption in, or adsorption on, a thin polymer
coating fixed to the solid surface of a fiber, inside an injection needle or inside a capillary. In this paper, the present
state of practical performance and of applications of SPME to the analysis of blood, urine, oral fluid and hair in clinical
and forensic toxicology is reviewed. The commercial coatings for fibers or needles have not essentially changed for many years,
but there are interesting laboratory developments, such as conductive polypyrrole coatings for electrochemically controlled
SPME of anions or cations and coatings with restricted-access properties for direct extraction from whole blood or immunoaffinity
SPME. In-tube SPME uses segments of commercial gas chromatography (GC) capillaries for highly efficient extraction by repeated
aspiration–ejection cycles of the liquid sample. It can be easily automated in combination with liquid chromatography but,
as it is very sensitive to capillary plugging, it requires completely homogeneous liquid samples. In contrast, fiber-based
SPME has not yet been performed automatically in combination with high-performance liquid chromatography. The headspace extractions
on fibers or needles (solid-phase dynamic extraction) combined with GC methods are the most advantageous versions of SPME
because of very pure extracts and the availability of automatic samplers. Surprisingly, substances with quite high boiling
points, such as tricyclic antidepressants or phenothiazines, can be measured by headspace SPME from aqueous samples. The applicability
and sensitivity of SPME was essentially extended by in-sample or on-fiber derivatization. The different modes of SPME were
applied to analysis of solvents and inhalation narcotics, amphetamines, cocaine and metabolites, cannabinoids, methadone and
other opioids, fatty acid ethyl esters as alcohol markers, γ-hydroxybutyric acid, benzodiazepines, various other therapeutic drugs, pesticides, chemical warfare agents, cyanide, sulfide
and metal ions. In general, SPME is routinely used in optimized methods for specific analytes. However, it was shown that
it also has some capacity for a general screening by direct immersion into urine samples and for pesticides and other semivolatile
substance in the headspace mode. 相似文献
17.
Rapid analysis of aflatoxins B1, B2, and ochratoxin A in rice samples using dispersive liquid–liquid microextraction combined with HPLC
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A novel, simple, and rapid method is presented for the analysis of aflatoxin B1, aflatoxin B2, and ochratoxin A in rice samples by dispersive liquid–liquid microextraction combined with LC and fluorescence detection. After extraction of the rice samples with a mixture of acetonitrile/water/acetic acid, mycotoxins were rapidly partitioned into a small volume of organic solvent (chloroform) by dispersive liquid–liquid microextraction. The three mycotoxins were simultaneously determined by LC with fluorescence detection after precolumn derivatization for aflatoxin B1 and B2. Parameters affecting both extraction and dispersive liquid–liquid microextraction procedures, including the extraction solvent, the type and volume of extractant, the volume of dispersive solvent, the addition of salt, the pH and the extraction time, were optimized. The optimized protocol provided an enrichment factor of approximately 1.25 and with detection of limits (0.06–0.5 μg/kg) below the maximum levels imposed by current regulations for aflatoxins and ochratoxin A. The mean recovery of three mycotoxins ranged from 82.9–112%, with a RSD less than 7.9% in all cases. The method was successfully applied to measure mycotoxins in commercial rice samples collected from local supermarkets in China. 相似文献
18.
A rapid, sensitive and environmentally friendly method for the analysis of 14 anilines in water samples by dispersive liquid–liquid
microextraction based on solidification of floating organic drop (DLLME-SFO) prior to gas chromatography–mass spectrometry
(GC-MS) was developed and optimized. In the proposed method, cyclohexane was used as the extraction solvent as its toxicity
was much lower than that of the solvent usually used in dispersive liquid–liquid microextraction (DLLME). In the optimized
conditions, the method exhibited good analytical performance. Based on a signal-to-noise ratio of 3, limits of detection for
anilines were in the range of 0.07 to 0.29 μg L−1, and the linear range was 0.5–200 μg L−1 with regression coefficients (r
2) higher than 0.9977. It was efficient for qualitative and quantitative analysis of anilines in water samples. The relative
standard deviations varied from 2.9 to 8.6 % depending on different compounds indicating good precision. Tap water and river
water were selected for evaluating the application to real water samples. The relative recoveries of anilines for the two
real samples spiked with 10 μg L−1 anilines were in the scope of 78.2–114.6 % and 77.3–115.6 %, respectively. 相似文献
19.
Zhou Y Han L Cheng J Guo F Zhi X Hu H Chen G 《Analytical and bioanalytical chemistry》2011,399(5):1901-1906
A method for analysis of diethofencarb and pyrimethanil in apple pulp and peel was developed by using dispersive liquid–liquid
microextraction based on solidification of a floating organic droplet (DLLME-SFO) and high-performance liquid chromatography
with diode-array detection (HPLC–DAD). Acetonitrile was used as the solvent to extract the two fungicides from apple pulp
and peel, assisted by microwave irradiation. When the extraction process was finished, the target analytes in the extraction
solvent were rapidly transferred from the acetonitrile extract to another extraction solvent (1-undecanol) by using DLLME-SFO.
Because of the lower density of 1-undecanol than that of water, the finely dispersed droplets of 1-undecanol collected on
the top of aqueous sample and solidified at low temperature. Meanwhile, the tiny particles of apple cooled and precipitated.
Recovery was tested for a concentration of 8 μg kg−1. Recovery of diethofencarb and pyrimethanil from apple pulp and peel was in the range 83.5–101.3%. The repeatability of the
method, expressed as relative standard deviation, varied between 4.8 and 8.3% (n = 6). Detection limits of the method for apple pulp and peel varied from 1.2–1.6 μg kg−1 for the two fungicides. Compared with conventional sample preparation, the method has the advantage of rapid speed and simple
operation, and has high enrichment factors and low consumption of organic solvent. 相似文献
20.
Layered double hydroxides are a family of inorganic crystals that have gained a lot of attention due to its special structure and properties such as high porosity, large specific area, and excellent anion exchange ability. In this work, flower‐like NiAl‐layered double hydroxides with high specific area were in situ immobilized onto the stainless steel fibers by bioinspired polydopamine modification method and packed into poly (ether ether) ketone tube for online solid‐phase microextraction with high performance liquid chromatography analysis. Thanks to the high specific surface area and excellent extraction ability of the NiAl‐layered double hydroxides, the fibers showed excellent extraction performance to three Sudan dyes with enrichment factors between 260 to 650 folds. After optimization of the reaction and extraction conditions, an online solid‐phase microextraction method was developed for determination of Sudan dyes in water samples and chili samples. The method has limits of detection of 0.01 to 0.02 ng/mL, good linearity and good reproducibility (≤1.45%). 相似文献