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1.
GC-MS determination of parabens,triclosan and methyl triclosan in water by in situ derivatisation and stir-bar sorptive extraction 总被引:1,自引:0,他引:1
Casas Ferreira AM Möder M Fernández Laespada ME 《Analytical and bioanalytical chemistry》2011,399(2):945-953
Stir-bar sorptive extraction in combination with an in situ derivatisation reaction and thermal desorption–gas chromatography–mass
spectrometry was successfully applied to determine parabens (methylparaben, isopropylparaben, n-propylparaben, butylparaben and benzylparaben), triclosan and methyltriclosan in water samples. This approach improves both
the extraction efficiency and the sensitivity in the GC in a simple way since the derivatisation reaction occurs at the same
time as the extraction procedure. The in situ derivatisation reaction was carried out with acetic anhydride under alkaline
conditions. Thermal desorption parameters (cryofocusing temperature, desorption flow, desorption time, desorption temperature)
were optimised using a Box–Behnken experimental design. All the analytes gave recoveries higher than 79%, except methylparaben
(22%). The method afforded detection limits between 0.64 and 4.12 ng/L, with good reproducibility and accuracy values. The
feasibility of the method for the determination of analytes in water samples was checked in tap water and untreated and treated
wastewater. 相似文献
2.
Prieto A Zuloaga O Usobiaga A Etxebarria N Fernández LA 《Analytical and bioanalytical chemistry》2008,390(2):739-748
A method for the determination of polybrominated diphenyl ethers (PBDEs) and polybrominated biphenyls (PBBs) in water samples
is proposed. The method involving stir bar sorptive extraction (SBSE) and thermal desorption followed by gas chromatography
coupled with mass spectrometry was optimised using statistical design of experiments. In the first place, the influence of
different polydimethylsiloxane stir bars was studied. A Plackett–Burman design was chosen to estimate the influence of five
factors on the efficiency of the SBSE process: desorption time (5–10 min), desorption temperature (250–300 °C), desorption
flow (50–100 mL min−1), cryofocusing temperature (-130 to 40 °C) and vent pressure (0–12.8 psi). Afterwards, two central composite designs were
used to find the optimal process settings that were applied to the optimisation of both desorption and extraction efficiency.
In the case of the desorption parameters, long desorption times (10 min) and desorption flows lower than 70 mL min-1 yielded the best signals for the majority of compounds. However, different behaviour among the analytes was observed for
the vent pressure and we decided to fix it at an intermediate value (7 psi). In the case of extraction parameters, the sample
volume and the addition of NaCl did not have a significant effect, while the addition of methanol yielded better extraction
responses. Remarkable recovery (82–106%) and repeatability (less than 18%) were attained. Furthermore, excellent regression
coefficients (r
2 = 0.991–0.999) and low detection limits (1.1–6.0 ng L−1) were also achieved for the congeners studied. The proposed method was applied to the analyses of PBDEs and PBBs in waters
from the Basque Country, Spain. 相似文献
3.
A simple and sensitive assay was developed and validated for the simultaneous quantification of rosuvastatin acid (RST), rosuvastatin-5S-lactone (RST-LAC), and N-desmethyl rosuvastatin (DM-RST), in buffered human plasma using liquid chromatography–tandem mass spectrometry (LC-MS/MS).
All the three analytes and the corresponding deuterium-labeled (d6) internal standards were extracted from 50 μL of buffered
human plasma by protein precipitation. The analytes were chromatographically separated using a Zorbax-SB Phenyl column (2.1 mm × 100 mm,
3.5 μm). The mobile phase comprised of a gradient mixture of 0.1% v/v glacial acetic acid in 10% v/v methanol in water (solvent A) and 40% v/v methanol in acetonitrile (solvent B). The analytes were separated at baseline within 6.0 min using a flow rate of 0.35 mL/min.
Mass spectrometry detection was carried out in positive electrospray ionization mode. The calibration curves for all three
analytes were linear (R ≥ 0.9964, n = 3) over the concentration range of 0.1–100 ng/mL for RST and RST-LAC, and 0.5–100 ng/mL for DM-RST. Mean extraction recoveries
ranged within 88.0–106%. Intra- and inter-run mean percent accuracy were within 91.8–111% and percent imprecision was ≤15%.
Stability studies revealed that all the analytes were stable in matrix during bench-top (6 h on ice–water slurry), at the
end of three successive freeze and thaw cycles and at −80°C for 1 month. The method was successfully applied in a clinical
study to determine the concentrations of RST and the lactone metabolite over 12-h post-dose in patients who received a single
dose of rosuvastatin. 相似文献
4.
P. Campíns-Falcó R. Herráez-Hernández J. Verdú-Andrés C. Cháfer-Pericás 《Analytical and bioanalytical chemistry》2009,394(2):557-565
This paper describes a cost-effective procedure for the analysis of short-chain aliphatic amines in water samples using a
solid-phase microextraction device. Analyte preconcentration and derivatisation were effected into a capillary column coated
with 95% polydimethylsiloxane–5% polydiphenylsiloxane, which was used as the injection loop of a Rheodyne injection valve.
The coating was previously loaded with the derivatisation reagent, 9-fluorenylmethyl chloroformate. A volume of 1 mL of samples
was then drawn into the capillary column, and the extracted analytes were left to react on the capillary coating for 5 min.
Next, the capillary column was cleaned by passing water. Finally, the injection valve was rotated, and the derivatives formed
were dynamically desorbed and transferred to the analytical column into the mobile phase. Methylamine, ethylamine, propylamine,
n-butylamine and n-pentylamine were selected as model compounds. Excellent sensitivity was achieved, being the limits of detection of 15–200 μg/L
when using UV detection and of 0.1–0.4 μg/L by fluorescence. 相似文献
5.
Connelly JT Kondapalli S Skoupi M Parker JS Kirby BJ Baeumner AJ 《Analytical and bioanalytical chemistry》2012,402(1):315-323
An integrated microfluidic biosensor is presented that combines sample pre-concentration and liposome-based signal amplification
for the detection of enteric viruses present in environmental water samples. This microfluidic approach overcomes the challenges
of long assay times of cell culture-based methods and the need to extensively process water samples to eliminate inhibitors
for PCR-based methods. Here, viruses are detected using an immunoassay sandwich approach with the reporting antibodies tagged
to liposomes. Described is the development of the integrated device for the detection of environmentally relevant viruses
using feline calicivirus (FCV) as a model organism for human norovirus. In situ fabricated nanoporous membranes in glass microchannels
were used in conjunction with electric fields to achieve pre-concentration of virus–liposome complexes and therefore enhance
the antibody–virus binding efficiency. The concentrated complexes were eluted to a detection region downstream where captured
liposomes were lysed to release fluorescent dye molecules that were then quantified using image processing. This system was
compared to an optimized electrochemical liposome-based microfluidic biosensor without pre-concentration. The limit of detection
of FCV of the integrated device was at 1.6 × 105 PFU/mL, an order of magnitude lower than that obtained using the microfluidic biosensor without pre-concentration. This significant
improvement is a key step toward the goal of using this integrated device as an early screening system for viruses in environmental
water samples. 相似文献
6.
Manuela Haunschmidt Christian W. Klampfl Wolfgang Buchberger Robert Hertsens 《Analytical and bioanalytical chemistry》2010,397(1):269-275
A screening method for analyzing environmental waters contaminated with UV filters using direct analysis in real-time mass
spectrometry (DART-MS) was developed. To demonstrate the suitability of DART-MS a test set of seven organic UV filters, namely
benzophenone-3 (BP-3), ethylhexyl dimethyl p-aminobenzoate (OD-PABA), 4-t-butyl-4′-methoxydibenzoylmethane (BM-DBM), homomethyl salicylate (HMS), 2-(ethylhexyl) salicylate (EHS), octocrylene (OC),
and 4-methylbenzylidene camphor (4-MBC), was defined. In the first step, standard solutions of the analytes prepared in methanol
were investigated in order to determine optimum parameters for the DART-MS. Because of the very low concentrations of UV filters
expected in environmental water samples, a pre-concentration step using stir bar sorptive extraction was performed. DART-MS
allows the direct, simple and rapid semi-quantitative analysis of the analytes enriched on the surface of the polydimethylsiloxane-coated
stir bars. The optimized method provided calibration curves with correlation coefficients R > 0.959, repeatability from 5% (for 4-MBC) to 30% (for BM-DBM) relative standard deviation and limits of detection lower
than 40 ng L−1 for all analytes. Finally, real lake water samples from locations with typical leisure activities were analyzed. Results
obtained with the developed DART-MS method were cross-checked by confirmatory analysis using thermodesorption gas chromatography
mass spectrometry (TD-GC-MS). Thereby, it could be demonstrated that both analytical methods provide comparable concentrations
for the UV filters in the lake water samples. 相似文献
7.
Moriarty M Lee A O'Connell B Kelleher A Keeley H Furey A 《Analytical and bioanalytical chemistry》2011,401(8):2481-2493
Serotonin is a major neurotransmitter and affects various functions both in the brain and in the rest of the body. It has
been demonstrated that altered serotinergic function is implicated in various psychiatric disorders including depression and
schizophrenia. Serotonin has also been implicated along with dopamine in attention deficit–hyperkinetic disorder (AD-HKD).
This study provides a versatile validated method for the analysis of serotonin, hydroxyindole acetic acid and dopamine in
urine using LC-MS/MS. This method was then used to quantify these analytes in a test group of 17 children diagnosed with severe
AD-HKD. This group was compared to a matched control group to investigate the possibility that one of these compounds may
be a potential biomarker for this condition. The developed method provided good linear calibration curves for the multiplex
assay of analytes in urine (0.05–3.27 nmol/L; R
2 ≥ 0.9977). Acceptable inter-day repeatability was achieved for all analytes with RSD values (n = 9) ranging from 1.1% to 9.3% over a concentration range of 0.11–3.27 μmol/L in urine. Excellent limits of detection (LOD)
and limits of quantitation (LOQ) were achieved with LODs of 8.8–18.2 nmol/L and the LOQs of 29.4–55.7 nmol/L for analytes
in urine. Recoveries were in the ranges of 98–104%, 100–106% and 91–107% for serotonin, 5-HIAA and dopamine, respectively.
An appropriate sample clean-up procedure for urine was developed to ensure efficient recovery and reproducibility on analysis.
Evaluation of matrix effects was also carried out and the influence of ion suppression on analytical results reported. Confirmatory
analysis was carried out on a linear trap quadrupole-Orbitrap mass spectrometer to obtain high mass accuracy data of the target
analytes in the clinical samples. 相似文献
8.
Timothy B. Jordan David S. Nichols Neil I. Kerr 《Analytical and bioanalytical chemistry》2009,394(8):2257-2266
In environmental analyses there is an ever-increasing need to develop simple and sensitive multi-residue methods. In many
agricultural regions, there is particular concern of the potential for pesticides to enter rivers and other waterways. This
study reports on the development and validation of a multi-residue method of analysis for 30 pesticides in water samples using
solid-phase extraction (SPE) followed by LC-MS/MS. The electrospray and MS/MS parameters were optimised for each pesticide,
including capillary voltage, collision-induced dissociation voltage, and selection of a precursor ion and two product ions.
A variety of SPE sorbents were tested for sample pre-concentration, including numerous polymeric based phases. Bond Elut PPL
and Oasis HLB were the only phases capable of retaining the majority of the target analyte classes in a single method. An
off-line pre-concentration method using a Gilson Aspec system was optimised using the Bond Elut PPL cartridges, with a concentration
factor of 25 producing limits of quantitation in the order of 6–100 ng/L. Excellent linearity (r
2 > 0.9), precision (<20%) and recovery (>60%) was obtained for nearly all of the analytes, covering a wide variety of chemical
and physical properties. This is the first study to fully validate Bond Elut PPL cartridges for use in multi-residue pesticide
analysis. 相似文献
9.
Clavijo CF Hoffman KL Thomas JJ Carvalho B Chu LF Drover DR Hammer GB Christians U Galinkin JL 《Analytical and bioanalytical chemistry》2011,400(3):715-728
Opioids such as morphine are the cornerstone of pain treatment. The challenge of measuring the concentrations of morphine
and its active metabolites in order to assess human pharmacokinetics and monitor therapeutic drugs in children requires assays
with high sensitivity in small blood volumes. We developed and validated a semi-automated LC-MS/MS assay for the simultaneous
quantification of morphine and its active metabolites morphine 3β-glucuronide (M3G) and morphine 6β-glucuronide (M6G) in human
plasma and in dried blood spots (DBS). Reconstitution in water (DBS only) and addition of a protein precipitation solution
containing the internal standards were the only manual steps. Morphine and its metabolites were separated on a Kinetex 2.6-μm
PFP analytical column using an acetonitrile/0.1% formic acid gradient. The analytes were detected in the positive multiple
reaction mode. In plasma, the assay had the following performance characteristics: range of reliable response of 0.25–1000 ng/mL
(r
2 > 0.99) for morphine, 1–1,000 ng/mL (r
2 > 0.99) for M3G, and 2.5–1,000 ng/mL for M6G. In DBS, the assay had a range of reliable response of 1–1,000 ng/mL (r
2 > 0.99) for morphine and M3G, and of 2.5–1,000 ng/mL for M6G. For inter-day accuracy and precision for morphine, M3G and
M6G were within 15% of the nominal values in both plasma and DBS. There was no carryover, ion suppression, or matrix interferences.
The assay fulfilled all predefined acceptance criteria, and its sensitivity using DBS samples was adequate for the measurement
of pediatric pharmacokinetic samples using a small blood of only 20–50 μL. 相似文献
10.
Delhomme O Raeppel C Teigné D Briand O Millet M 《Analytical and bioanalytical chemistry》2011,399(3):1325-1334
To measure dermal exposure of a non-agricultural occupationally exposed population to pesticides, a new method has been developed
for analysis of 13 pesticides from different classes (fungicides, herbicides, insecticides) on dermal patches. The method
includes extraction of the patches and analysis of the pesticides by GC–MS and/or HPLC–fluorescence. Water-soluble pesticides
(glyphosate and glufosinate) on patches were ultrasonically extracted twice with ultra-pure water for 10 min and analysed
by HPLC–fluorescence after derivatisation with FMOC. Organic-soluble pesticides (bifenthrin, cyprodinil, difufenicanil, fludioxonil,
oxadiazon, pyriproxyfen, clopyralid, 2,4-D, fluroxypyr, 2,4-MCPA, and triclopyr) were extracted ultrasonically twice for 10 min
with 70:30 dichloromethane–acetonitrile and analysed by GC–MS directly or after derivatisation with N-methyl-N-tert-butyldimethylsilyltrifluoroacetamide. Detection limits varied between 3 and 4 μg L−1 for water-soluble pesticides and between 1 and 10 μg L−1 for organic-soluble pesticides. 相似文献
11.
N. Negreira I. Rodríguez E. Rubí R. Cela 《Analytical and bioanalytical chemistry》2010,398(2):995-1004
The performance of the dispersive liquid–liquid microextraction (DLLME) technique for the determination of eight UV filters
and a structurally related personal care species, benzyl salicylate (BzS), in environmental water samples is evaluated. After
extraction, analytes were determined by gas chromatography combined with mass spectrometry detection (GC-MS). Parameters potentially
affecting the performance of the sample preparation method (sample pH, ionic strength, type and volume of dispersant and extractant
solvents) were systematically investigated using both multi- and univariant optimization strategies. Under final working conditions,
analytes were extracted from 10 mL water samples by addition of 1 mL of acetone (dispersant) containing 60 μL of chlorobenzene
(extractant), without modifying either the pH or the ionic strength of the sample. Limits of quantification (LOQs) between
2 and 14 ng L−1, inter-day variability (evaluated with relative standard deviations, RSDs) from 9% to 14% and good linearity up to concentrations
of 10,000 ng L−1 were obtained. Moreover, the efficiency of the extraction was scarcely affected by the type of water sample. With the only
exception of 2-ethylhexyl-p-dimethylaminobenzoate (EHPABA), compounds were found in environmental water samples at concentrations between 6 ± 1 ng L−1 and 26 ± 2 ng mL−1. 相似文献
12.
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
13.
A. Prieto O. Basauri R. Rodil A. Usobiaga L.A. Fernández N. Etxebarria O. Zuloaga 《Journal of chromatography. A》2010,1217(16):2642-2666
Introduced in 1999 as a novel solventless sample preparation method, stir-bar sorptive extraction (SBSE) has become a popular analytical technique for the pre-concentration of organic compounds into a polydimethylsiloxane (PDMS)-coated stir-bar. In the last 10 years, hundreds of applications in the environmental, food and biomedical fields can be found in the literature. However, only PDMS-coated stir-bars are commercially available, which reduces the applicability of SBSE to the extraction of the non-polar compounds due to the poor extractability of more polar analytes. In this review, a view on method optimisation, limitations, potential solutions such as in-house coatings and derivatisation and novel applications in multi-residue analysis and passive sampling are revised. 相似文献
14.
Antonia María Carro Paula González Noelia Fajar Rosa Antonia Lorenzo Rafael Cela 《Analytical and bioanalytical chemistry》2009,394(3):893-901
The headspace solid-phase micro-extraction technique with on-fibre derivatisation followed by gas chromatography-tandem mass
spectrometry has been evaluated for the analysis of 1,3-dichloro-2-propanol in water. An asymmetric factorial design has been
performed to study the influence of five experimental factors: extraction time and temperature, derivatisation time and temperature
and pH. The best extraction performance is achieved in the headspace mode, with 5 mL stirred water samples (pH 4) containing
1.3 g of NaCl, equilibrated for 30 min at 25 °C, using divinylbenzene-carboxen-polydimethylsiloxane as the fibre coating.
On-fibre derivatisation has been used for the first time with 50 μL of bis(trimethylsilyl)trifluoroacetamide at 25 °C during
15 min, leading to effective yields. The proposed method provides high sensitivity, good linearity and repeatability (relative
standard deviation of 5.1% for 10 ng mL−1 and n = 5). The limits of detection and quantification were 0.4 and 1.4 ng mL−1, respectively. Analytical recoveries obtained for different water samples were approx. 100%. 相似文献
15.
Victoria F. Samanidou Emmanouil D. Tsochatzis Ioannis N. Papadoyannis 《Mikrochimica acta》2008,160(4):471-475
An HPLC method was developed and validated for the determination of the cephalosporins cefotaxime and cephalexine in skimmed
bovine milk. The analytical column, Kromasil C18 (250 mm × 4.0 mm, 5 μm) was operated at ambient temperature. Mobile phase consisted of CH3OH-acetate buffer (pH = 4.0) and it was delivered isocratically at a flow rate of 1.0 mL · min−1. Total analysis time was less than 5 min. Caffeine was used as internal standard (5 ng · μL−1). UV detection was performed at 265 nm. Method validation was performed by means of intra-day (n = 5) and inter-day accuracy and precision (n = 8), sensitivity and linearity. Limits of detection (LOD) and limits of quantification (LOQ) were 0.1 and 0.3 ng · μL−1, respectively. The method was applied to the analysis of a veterinary drug (CEPOREX) containing cephalexine. The results
were quite accurate with the relative error varying from −8.0 to −3.5%. Solid-phase extraction was applied to remove all matrix
interference from milk samples. High extraction recoveries (average 84–121%) were achieved by using Abselut NEXUS cartridges
with acetonitrile as eluent and a rinsing step with water and n-butanol. A pre-concentration step was necessary in a 1/10
level to reach the EU MRL concentration level (100 μg · kg−1). RSD values were less than 7% for both cephalosporins.
Correspondence: Ioannis N. Papadoyannis, Laboratory of Analytical Chemistry, Department of Chemistry, Aristotle University
of Thessaloniki, GR-54124 Thessaloniki, Greece 相似文献
16.
Federica Bianchi Monica Mattarozzi Maria Careri Alessandro Mangia Marilena Musci Francesca Grasselli Simona Bussolati Giuseppina Basini 《Analytical and bioanalytical chemistry》2010,396(7):2639-2645
A simple and easily automable method based on solid-phase microextraction followed by gas chromatographic–mass spectrometric
analysis was developed for the determination of two potential angiogenesis modulators 17β-estradiol (17-BE) and 2-methoxyestradiol
(2-MEOE) in culture media. Trifluoroacetic anhydride was used as the derivatising agent. A homemade octadecyl silica coating,
characterised by a coating thickness of 72 ± 10 μm and a good thermal stability until 250 °C, was prepared. Experimental design
was used to optimise the extraction conditions in terms of derivatisation time, derivatisation temperature and time of extraction.
As for method validation, lower limits of quantification of 0.17 and 0.015 μg/l for 17β-estradiol and 2-methoxyestradiol,
respectively, were obtained. Finally, the capabilities of the developed fibres were evaluated for the analysis of the investigated
analytes developed by granulosa cells in culture media maintained under normoxic, hypoxic and anoxic conditions, in order
to better elucidate their possible role in the angiogenic process. An increase of the production of both 17-BE and 2-MEOE
in hypoxic and anoxic conditions seems to be related to the effect of oxygen deprivation. 相似文献
17.
Benito-Peña E Martins S Orellana G Moreno-Bondi MC 《Analytical and bioanalytical chemistry》2009,393(1):235-245
A novel water-compatible molecularly imprinted polymer (MIP), prepared with enrofloxacin (ENR) as the template, has been optimised
for the selective extraction of fluoroquinolone antibiotics in aqueous media. The results of a morphological characterisation
and selectivity tests of the polymer material for ENR and related derivatives are reported. High affinity for the piperazine-based
fluoroquinolones marbofloxacin, ciprofloxacin, norfloxacin and ofloxacin was observed, whereas no retention was found for
nonrelated antibiotics. Various parameters affecting the extraction efficiency of the polymer have been optimised to achieve
selective extraction of the antibiotics from real samples and to reduce nonspecific interactions. These findings resulted
in a MISPE/HPLC-FLD method allowing direct extraction of the analytes from aqueous samples with a selective wash using just
50% (v/v) organic solvent. The method showed excellent recoveries and precision when buffered urine samples fortified at five
concentration levels (25–250 ng mL−1 each) of marbofloxacin, ciprofloxacin, norfloxacin, enrofloxacin and sarafloxacin were tested (53–88%, RSD 1–10%, n = 3). Moreover, the biological matrix of the aqueous samples did not influence the preconcentration efficiency of the fluoroquinolones
on the MIP cartridges; no significant differences were observed between the recovery rates of the antibiotics in buffer and
urine samples. The detection limits of the whole process range between 1.9 and 34 ng mL–1 when 5-mL urine samples are processed. The developed method has been successfully applied to preconcentration of norfloxacin
in urine samples of a medicated patient, demonstrating the ability of the novel MIP for selective extraction of fluoroquinolones
in urine samples. 相似文献
18.
Shao-Wen Zhang Jun Xing Ling-Shuang Cai Cai-Ying Wu 《Analytical and bioanalytical chemistry》2009,395(2):479-487
Urinary 8-hydroxy-2′-deoxyguanosine (8-OHdG) has been widely used as a biomarker of oxidative DNA damage. Measurements of
8-OHdG in urinary samples are challenging owing to the low level of 8-OHdG and the complex matrix. In this study, a novel
molecularly imprinted polymer (MIP) monolithic column was synthesized with guanosine as a dummy template which was used as
the medium for in-tube solid-phase microextraction (SPME). In-tube SPME coupled with HPLC/UV detection for extraction and
determination of urinary 8-OHdG was developed. The synthesized MIP monolithic column exhibited high extraction efficiency
owing to its greater phase ratio with convective mass transfer and inherent selectivity. The enrichment factor for 8-OHdG
was found to be 76 and the limits of detection and quantification of the method for urinary samples were 3.2 nmol/L (signal-to-noise
ratio 3) and 11 nmol/L (signal-to-noise ratio 10), respectively. The MIP’s selectivity also made the sample preparation procedure and chromatographic separation much easier. The linear range of the
proposed method was from 0.010 to 5.30 μmol/L (r = 0.9997), with a relative standard deviation of 1.1–6.8%, and the recovery for spiked urine samples was 84 ± 3%. The newly
developed method was successfully applied to determine urinary samples of healthy volunteers, coking plant workers, and cancer
patients. The 8-OHdG level in cancer patients was significantly higher than that in healthy people. 相似文献
19.
Macwan JS Ionita IA Dostalek M Akhlaghi F 《Analytical and bioanalytical chemistry》2011,400(2):423-433
The aim of the proposed work was to develop and validate a simple and sensitive assay for the analysis of atorvastatin (ATV)
acid, ortho- and para-hydroxy-ATV, ATV lactone, and ortho- and para-hydroxy-ATV lactone in human plasma using liquid chromatography-tandem mass spectrometry. All six analytes and corresponding
deuterium (d5)-labeled internal standards were extracted from 50 μL of human plasma by protein precipitation. The chromatographic
separation of analytes was achieved using a Zorbax-SB Phenyl column (2.1 mm × 100 mm, 3.5 μm). The mobile phase consisted
of a gradient mixture of 0.1% v/v glacial acetic acid in 10% v/v methanol in water (solvent A) and 40% v/v methanol in acetonitrile (solvent B). All analytes including ortho- and para-hydroxy metabolites were baseline-separated within 7.0 min using a flow rate of 0.35 mL/min. Mass spectrometry detection was
carried out in positive electrospray ionization mode, with multiple-reaction monitoring scan. The calibration curves for all
analytes were linear (R
2 ≥ 0.9975, n = 3) over the concentration range of 0.05–100 ng/mL and with lower limit of quantitation of 0.05 ng/mL. Mean extraction recoveries
ranged between 88.6–111%. Intra- and inter-run mean percent accuracy were between 85–115% and percent imprecision was ≤ 15%.
Stability studies revealed that ATV acid and lactone forms were stable in plasma during bench top (6 h on ice-water slurry),
at the end of three successive freeze and thaw cycles and at −80 °C for 3 months. The method was successfully applied in a
clinical study to determine concentrations of ATV and its metabolites over 12 h post-dose in patients receiving atorvastatin. 相似文献
20.
?zlem Aksu D?nmez Abdürrezzak Bozdo?an G?nül Kunt 《Monatshefte für Chemie / Chemical Monthly》2006,35(6):1163-1168
A partial least-squares calibration (PLS) method has been developed for simultaneous quantitative determination of escin (ES) and diethylamine salicylate (DAS) in pharmaceutical preparations. The resolution of these mixtures has been accomplished without prior separation or derivatisation,
by using partial least-squares (PLS-2) regression analysis of electronic absorption spectral data. The experimental calibration
matrix was constructed with 9 samples. The concentration ranges considered were 10, 20, 30 (ES) and 40, 50, 60 (DAS) μg cm−3. The absorbances were recorded between 200 and 325 nm every 5 nm. Proposed method was compared with conventional spectrophotometric
method. The results show that PLS-2 is a simple, rapid, and accurate method applied to the determination of these compounds
in pharmaceuticals. 相似文献