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1.
Hasegawa C Kumazawa T Lee XP Marumo A Shinmen N Seno H Sato K 《Analytical and bioanalytical chemistry》2007,389(2):563-570
Methamphetamine and amphetamine were extracted from human whole blood samples using pipette tip solid-phase extraction (SPE)
with MonoTip C18 tips, on which C18-bonded monolithic silica gel was fixed. Human whole blood (0.1 mL) containing methamphetamine and amphetamine, with N-methylbenzylamine as an internal standard, was mixed with 0.4 mL of distilled water and 50 μL of 5 M sodium hydroxide solution.
After centrifugation, the supernatant was extracted to the C18 phase of the tip (pipette tip volume, 200 μL) by 25 repeated aspirating/dispensing cycles using a manual micropipettor. Analytes
retained in the C18 phase were eluted with methanol by five repeated aspirating/dispensing cycles. After derivatization with trifluoroacetic
anhydride, analytes were measured by gas chromatography – mass spectrometry with selected ion monitoring in the positive-ion
electron impact mode. Recoveries of methamphetamine and amphetamine spiked into whole blood were more than 87.6 and 81.7%,
respectively. Regression equations for methamphetamine and amphetamine showed excellent linearity in the range of 0.5–100 ng/0.1 mL.
The limits of detection for methamphetamine and amphetamine were 0.15 and 0.11 ng/0.1 mL, respectively. Intra- and interday
coefficients of variation for both stimulants were not greater than 9.6 and 13.8%, respectively. The determination of methamphetamine
and amphetamine in autopsy whole blood samples is presented, and was shown to validate the present methodology. 相似文献
2.
Mequitazine has been found to be extractable from human plasma samples using MonoTip C18 tips, inside which C18-bonded monolithic silica gel was fixed. Human plasma (0.1 mL) containing mequitazine and cyproheptadine as an internal standard (IS) was mixed with 0.4 mL of distilled water and 25 μL of 1 M potassium phosphate buffer (pH 8.0). After centrifugation of the mixture, the supernatant fraction was extracted to the C18 phase of the tip by 25 repeated aspirating/dispensing cycles using a manual micropipettor. The analytes retained on the C18 phase were then eluted with methanol by five repeated aspirating/dispensing cycles. Without evaporation and reconstitution, the eluate was injected into a gas chromatograph injector and detected by a mass spectrometer with selected ion monitoring in the positive-ion electron impact mode. The separation of mequitazine and the IS from each other and from impurities was generally satisfactory using a DB-1MS capillary column (30 m × 0.32 mm i.d., film thickness 0.25 μm). The recoveries of mequitazine and the IS spiked into plasma were more than 90.0%. The regression equation for mequitazine showed excellent linearity in the range of 0.2-200 ng 0.1 mL−1, and the detection limit was 0.05 ng 0.1 mL−1of plasma. The intra-day and inter-day coefficients of variation for mequitazine in human plasma were not greater than 8.16 and 9.24%, respectively. Accuracy for the drug was in the range of 90.0-97.4%. The data obtained from determination of mequitazine in human plasma after oral administration of the drug are also presented. 相似文献
3.
A fast and sensitive liquid chromatography–mass spectrometry method was developed for the determination of ursolic acid (UA)
in rat plasma and tissues. Glycyrrhetinic acid was used as the internal standard (IS). Chromatographic separation was performed
on a 3.5 μm Zorbax SB-C18 column (30 mm × 2.1 mm) with a mobile phase consisting of methanol and aqueous 10 mM ammonium acetate
using gradient elution. Quantification was performed by selected ion monitoring with (m/z)− 455 for UA and (m/z)− 469 for the IS. The method was validated in the concentration range of 2.5 − 1470 ng mL−1 for plasma samples and 20 − 11760 ng g−1 for tissue homogenates. The intra- and inter-day assay of precision in plasma and tissues ranged from 1.6% to 7.1% and 3.7%
to 9.0%, respectively, and the intra- and inter-day assay accuracy was 84.2 − 106.9% and 82.1 − 108.1%, respectively. Recoveries
in plasma and tissues ranged from 83.2% to 106.2%. The limits of detections were 0.5 ng mL−1 or 4.0 ng g−1. The recoveries for all samples were >90%, except for liver, which indicated that ursolic acid may metabolize in liver. The
main pharmacokinetic parameters obtained were T
max = 0.42 ± 0.11 h, C
max = 1.10 ± 0.31 μg mL−1, AUC = 1.45 ± 0.21 μg h mL−1 and K
a = 5.64 ± 1.89 h−1. The concentrations of UA in rat lung, spleen, liver, heart, and cerebellum were studied for the first time. This method
is validated and could be applicable to the investigation of the pharmacokinetics and tissue distribution of UA in rats. 相似文献
4.
Lee XP Hasegawa C Kumazawa T Shinmen N Shoji Y Seno H Sato K 《Journal of separation science》2008,31(12):2265-2271
A method for the simultaneous extraction of four tricyclic antidepressants from human plasma samples using pipette tip SPE with MonoTip C(18) tips is presented. Human plasma (0.1 mL) containing four tricyclic antidepressants (amitriptyline, amoxapine, imipramine, and trimipramine) and an internal standard (IS), protriptyline, was mixed with 0.4 mL of distilled water and 100 microL 1 M NaOH solution. After centrifugation of the mixture, the supernatant was extracted to the C(18) phase of the tip by 20 repeated aspirating/dispensing cycles using a manual micropipettor. The analytes retained in the tip were eluted with methanol by five repeated aspirating/dispensing cycles. Without evaporation and reconstitution, the eluate was directly injected into a gas chromatograph injector and detected by a mass spectrometer with SIM in the positive-ion electron impact mode. Recovery of the four antidepressants and IS spiked into human plasma was 80.2-92.1%. The regression equations for the four antidepressants showed excellent linearity in the range of 0.2-40 ng/0.1 mL. LODs and LOQs for the four drugs were 0.05-0.2 ng/0.1 mL and 0.2-0.5 ng/0.1 mL, respectively. Intra- and interday CVs for the four drugs in plasma were no greater than 9.5%. 相似文献
5.
Cahill MG Caprioli G Stack M Vittori S James KJ 《Analytical and bioanalytical chemistry》2011,400(2):587-594
Effluent from wastewater treatment plants have been identified as an important source of micro-organic contaminants in the
environment. An online high-performance liquid chromatography–heated electrospray ionization tandem mass spectrometric method
was developed and validated for the determination of basic pesticides in effluent wastewaters. Most available methods for
pesticide analysis of wastewater samples are time-consuming, require complex clean-up steps and are difficult to automate.
The method developed used a simple solid-phase extraction clean-up for salt and lipid reduction. On-line sample pre-concentration
was performed using a reversed phase (C18) column, and analytes were separated by back-flushing onto an analytical column (C8) with detection using QqQ MS. An option to increase MS resolution was exploited to minimize interference from endogenous
compounds in the matrix. A better than unit mass resolution was used (Q1 full width half maximum (FWHM) = 0.2 Da and Q3 FWHM = 0.7 Da),
which was as rugged as a unit resolution method, and improved signal/noise and better detection limits were achieved for the
targeted basic pesticides. This method was applied to the determination of 11 pesticides, including methoxytriazine, chlorotriazines,
chloroacetanilides, phenylurea and carbamate pesticides. The percentage recovery values for these pesticides using the online
trapping column were within the range, 73–95%, with relative standard deviation (RSD) values <8.9%. The highest concentrations
of these pesticides in wastewater effluents in County Cork, Ireland, were simazine (0.51 μg/L), prometon (0.14 μg/L), diuron
(0.21 μg/L) and atrazine (0.19 μg/L). 相似文献
6.
Babu Rao Chandu Sreekanth Nama Kanchanamala Kanala Balasekhara Reddy Challa Rihana Parveen Shaik Mukkanti Khagga 《Analytical and bioanalytical chemistry》2010,398(3):1367-1374
A novel simple, sensitive, selective, and rapid high-performance liquid chromatography coupled with tandem mass spectrometry
method was developed and validated for quantification of riluzole in human plasma. The chromatography was performed by using
a Zorbax-SB-C18 (4.6 × 75 mm, 3.5 μm) column , isocratic mobile phase 0.1% formic acid/acetonitrile (10:90 v/v), and an isotope-labeled
internal standard (IS), [13C,15N2]riluzole. The extraction of drug and internal standard was performed by liquid–liquid extraction and analyzed by MS in the
multiple reaction monitoring (MRM) mode using the respective [M+H]+ ions, m/z 235.0/165.9 for riluzole and m/z 238.1/169.0 for the IS. The calibration curve was linear over the concentration range 0.5–500.0 ng/ml for riluzole in human
plasma. The limit of quantification (LOQ) was demonstrated at 0.5 ng/ml. The within-batch and between-batch precision were
0.6–2.3% and 1.4–5.7%, and accuracy was 97.1–101.1% and 98.8–101.2% for riluzole respectively. Drug and IS were eluted within
3.0 min. The validated method was successfully applied in a bioequivalence study of riluzole in human plasma. 相似文献
7.
Jaisson S Gorisse L Pietrement C Gillery P 《Analytical and bioanalytical chemistry》2012,402(4):1635-1641
Homocitrulline (HCit), an amino acid formed by the carbamylation of ε-amino groups of lysine residues, is considered a promising
biomarker for monitoring diseases such as chronic renal failure and atherosclerosis. This paper describes a tandem mass spectrometric
method for total, protein-bound and free HCit measurement in plasma samples. HCit was separated from other plasma components
by hydrophilic interaction liquid chromatography. Detection was achieved by monitoring transitions of 190.1 > 127.1 and 190.1 > 173.1
for HCit, and 183.1 > 120.2 for d7-citrulline used as internal standard. This method allowed HCit quantification within 5.2 min and was precise (inter-assay
CV < 5.85%), accurate (mean recoveries ranging from 97% to 106%), and exhibited a good linearity from 10 nmol/L to 1.6 μmol/L.
Plasma samples from control and uremic mice (n = 10) were analyzed. In control mice, mean total plasma HCit concentration was 0.78 ± 0.12 μmol/mol amino acids, whereas
it was increased 2.7-fold in uremic mice plasma, reaching 2.10 ± 0.50 μmol/mol amino acids (p < 0.001). In conclusion, this method exhibits good analytical performances and meets the criteria of sensitivity suitable
for HCit concentration assessment in plasma samples. 相似文献
8.
M. Reska E. Ochsmann T. Kraus T. Schettgen 《Analytical and bioanalytical chemistry》2010,397(8):3563-3574
Styrene is one of the most important industrial chemicals, with an enormously high production volume worldwide. The urinary
mercapturic acids of its metabolite styrene-7,8-oxide, namely N-acetyl-S-(2-hydroxy-1-phenylethyl)-l-cysteine (PHEMA 1) and N-acetyl-S-(2-hydroxy-2-phenylethyl)-l-cysteine (PHEMA 2), are specific biomarkers for the determination of individual internal exposure to this highly reactive
intermediate of styrene. We have developed and validated a fast, specific and very sensitive method for the accurate determination
of the sum of phenylhydroxyethyl mercapturic acids (PHEMAs) in human urine with an automated multidimensional liquid chromatography–tandem
mass spectrometry method using 13C6-labelled PHEMAs as internal standards. Analytes were stripped from the urinary matrix by online extraction on a restricted
access material, transferred to the analytical column and subsequently determined by tandem mass spectrometry. The limit of
quantification (LOQ) for the sum of PHEMAs was 0.3 μg/L urine and allowed us to quantify the background exposure of the (smoking)
general population. Precision within series and between series ranged from 1.5 to 6.8% at three concentrations ranging from
3 to 30 μg/L urine; the mean accuracy was between 104 and 110%. We applied the method to spot urine samples from 40 subjects
of the general population with no known occupational exposure to styrene. The median levels (range) for the sum of PHEMAs
in urine of non-smokers (n = 22) were less than 0.3 μg/L (less than 0.3 to 1.1 μg/L), whereas in urine of smokers (n = 18), the median levels were 0.46 μg/L (less than 0.3 to 2.8 μg/L). Smokers showed a significantly higher excretion of the
sum of PHEMAs (p = 0.02). Owing to its automation and high sensitivity, our method is well suited for application in occupational or environmental
studies. 相似文献
9.
Takeshi Kumazawa Koichi Saeki Isao Yanagisawa Seisaku Uchigasaki Chika Hasegawa Hiroshi Seno Osamu Suzuki Keizo Sato 《Analytical and bioanalytical chemistry》2009,394(4):1161-1170
This paper describes a fully automated on-line method combining in-tube solid-phase microextraction (SPME) in which sample
clean-up and enrichment are conducted through an open tubular fused-silica capillary column and high-performance liquid chromatography
(HPLC)/tandem mass spectrometry (MS/MS) detection for the determination of six butyrophenone derivatives (moperone, floropipamide,
haloperidol, spiroperidol, bromperidol, and pimozide) in human plasma samples. The six butyrophenones were extracted by repeatedly
aspirating and dispensing plasma sample solutions on a DB-17 capillary column (60 cm × 0.32 mm i.d., film thickness 0.25 μm).
The analytes retained on the inner surface of the capillary column were then eluted into an acetonitrile-rich mobile phase
using a gradient separation technique. Extraction efficiencies ranged from 12.7% to 31.8% for moperone, spiroperidol, and
pimozide, and from 1.08% to 4.86% for floropipamide, haloperidol, and bromperidol. The regression equations for all compounds
showed excellent linearity, ranging from 0.05 to 50 ng/0.1 mL of plasma, except for moperone and spiroperidol (0.01 to 50 ng/0.1 mL).
The limits of detection and quantification in plasma for each drug were 0.03–0.2 and 0.1–0.5 ng/mL, respectively. The intra-
and inter-day coefficients of variation for all compounds in plasma were not greater than 13.7%. 相似文献
10.
Minakata K Nozawa H Gonmori K Yamagishi I Suzuki M Hasegawa K Watanabe K Suzuki O 《Analytical and bioanalytical chemistry》2011,400(7):1945-1951
An electrospray ionization tandem mass spectrometric (ESI-MS-MS) method has been developed for the determination of cyanide
(CN–) in blood. Five microliters of blood was hemolyzed with 50 μL of water, then 5 μL of 1 M tetramethylammonium hydroxide solution
was added to raise the pH of the hemolysate and to liberate CN– from methemoglobin. CN– was then reacted with NaAuCl4 to produce dicyanogold, Au(CN)2–, that was extracted with 75 μL of methyl isobutyl ketone. Ten microliters of the extract was injected directly into an ESI-MS-MS
instrument and quantification of CN– was performed by selected reaction monitoring of the product ion CN– at m/z 26, derived from the precursor ion Au(CN)2– at m/z 249. CN– could be measured in the quantification range of 2.60 to 260 μg/L with the limit of detection at 0.56 μg/L in blood. This
method was applied to the analysis of clinical samples and the concentrations of CN– in the blood were as follows: 7.13 ± 2.41 μg/L for six healthy non-smokers, 3.08 ± 1.12 μg/L for six CO gas victims, 730 ± 867 μg
for 21 house fire victims, and 3,030 ± 97 μg/L for a victim who ingested NaCN. The increase of CN– in the blood of a victim who ingested NaN3 was confirmed using MS-MS for the first time, and the concentrations of CN– in the blood, gastric content and urine were 78.5 ± 5.5, 11.8 ± 0.5, and 11.4 ± 0.8 μg/L, respectively. 相似文献
11.
A. N. Araújo José A. M. Catita José L. F. C. Lima Elias A. G. Zagatto 《Fresenius' Journal of Analytical Chemistry》1998,360(1):100-103
A monosegmented flow system (MCFA) is proposed to achieve slow enzymatic spectrophotometric determinations, here applied
to the determination of triglycerides in blood serum. The sample (4.5 μL), enzymatic reagent (150 μL) and an air plug (100 μL)
are simultaneously inserted into a carrier stream buffered to pH 7.9 (Tris ⋅ HCl). In order to avoid the cumbersome step of
air removal, a relocating detector was used. This system handles about 60 samples/h, yielding precise results (r.s.d. usually<2.5%).
Sensitivity is 56 mAU ⋅ L/mmol up to 6 mmol/L triglycerides. Accuracy was assessed by running 50 samples already analysed
by a conventional procedure yielding the equation CMCFA(mmol/L)=1.00(±0.04) CRef(mmol/L)−0.03(±0.08); r=0.990.
Received: 22 January 1997/Revised: 12 March 1997/Accepted: 28 March 1997 相似文献
12.
Liu Z Zhang B Liu Z Li S Li G Geng L Zhao X Bi K Tang X Chen X 《Analytical and bioanalytical chemistry》2012,403(1):323-330
A UPLC-ESI-MS/MS method has been developed and validated for the determination of larotaxel in beagle dog plasma. After addition
of the internal standard, plasma samples were extracted by liquid–liquid extraction with methyl tert-butyl ether and separated
on a 50 × 2.1 mm ACQUITY 1.7 μm C18 column (Waters, USA), with acetonitrile and 5 mM ammonium acetate as mobile phase, within a runtime of 3.0 min. The analytes
were detected without interference in Multiple Reaction Monitoring mode with positive electrospray ionization. The linear
range was 2.5–5,000 ng/mL. The intra-day and inter-day precisions (relative standard deviation, RSD, %) were within 9.3% and
10.2%, respectively, and the accuracy (relative error, RE, %) was less than 11.5%. The validated method was successfully applied
to a pharmacokinetic study of larotaxel in beagle dogs after intravenous administration of larotaxel-loaded lipid microsphere
with different doses of 0.4, 0.8, and 1.6 mg/kg. The area under the concentration–time curve and the peak concentration of
larotaxel seemed to increase with increasing dose proportionally, suggesting linear pharmacokinetics. 相似文献
13.
López-Flores J Fernández-de Córdova ML Molina-Díaz A 《Analytical and bioanalytical chemistry》2007,388(8):1771-1777
A flow injection–solid-phase spectroscopy (FI-SPS) system implemented with photochemically induced fluorescence (PIF) is described
for the rapid and very sensitive determination of reserpine in biological fluids and pharmaceutical formulations. An intensively
fluorescent photoproduct is in-line generated, retained on C18 silica gel in the detection area and monitored at 394/489 nm (λ
ex/λ
em). After the establishment of the appropriate working variables, the system is calibrated at two different injection volumes,
100 and 800 μL, achieving detection limits of 0.33 and 0.05 ng mL−1, respectively. The RSD for reserpine at 2 ng mL−1 (800 μL) was 1.5% (n = 10). The sampling rates were 46 and 43 h−1 for each injection volume, respectively. The potential interference of some common species coexisting with reserpine in the
analysed samples was also studied. The procedure was successfully applied to commercial formulations, urine and serum without
any previous treatment of samples. Recoveries ranged from 94.9 to 100.2%. 相似文献
14.
A new sample insertion device for the stabilized capacitive plasma (SCP) has been developed, which enables it to analyze
dry residues of micro amounts of liquid samples. Insertion was applied into an SCP as plasma source because of its good stability
and excitation properties as well as its low instrument and operation costs. The plasma is sustained at a frequency of 27.12 MHz
and an RF power of 150 W. For analysis the liquid samples are positioned at the tip of a quartz rod with the aid of a μL syringe.
Then the sample is dried and the sampling rod inserted into the plasma. After optimization of the carrier gas flow (5 L/h)
and the sample volume (20 μL) the detection limit for Pb with Ar as plasma gas is 200 pg.
By further improving the guidance of the insertion detection limits for Pb, Cu, Cd and Mg in the 1 to 30 ng/mL range or 20
to 600 pg range absolute were obtained. It was found that the detection limits in the case of He are better than those obtained
with Ar. The matrix interferences caused by changes in the concentration of the easily ionizable element Na were found to
be below 10% for Na concentrations of up to 0.45 μg/mL. Ethanol concentrations of up to 14% in the analyte solutions did not
cause any interferences.
Received December 17, 1998. Revision June 4, 1999. 相似文献
15.
Lina Kantiani Marinella Farré Josep Manuel Grases i Freixiedas Damià Barceló 《Analytical and bioanalytical chemistry》2010,398(3):1195-1205
A fully automated method has been developed for analysis of eighteen antibacterial compounds, including penicillins, cephalosporins
and sulfonamides, in animal feed with limits of quantification in the range 0.25–5.79 μg kg−1. The method is based on pressurized liquid extraction of 3 g homogenized feed with water and online clean-up of 500 μL of
the extract with C18HD cartridges. The purified sample was directly analysed by liquid chromatography–electrospray tandem mass spectrometry (SPE–LC–ESI-MS–MS).
Chromatographic separation was achieved within 10 min by use of a C12 Phenomenex Hydro-RP reversed-phase analytical column and a mobile phase gradient (water + 0.1% formic acid–methanol + 0.1%
formic acid). The method was validated, revealing capability for detection of concentrations as low as 0.09 μg kg−1, decision limits (CCα) and detection capabilities (CCβ) in the range 10–174 μg kg−1 and 22–182 μg kg−1, respectively, and inter-day precision ranging from 0.7 to 8.3%. Recovery, with internal standard correction, was in the
range 93–134% for all analytes. The method was then applied to analysis of fifteen feed samples, nine of which contained at
least one antimicrobial at concentrations between 0.006 and 1.526 mg kg−1. The performance data and results from the method were compared with those from a previous method developed by our group,
using offline SPE, by analyzing the same set of samples by both methods. The online SPE approach resulted in slightly improved
sensitivity, with LODs of 0.09–2.12 μg kg−1 compared with 0.12–3.94 μg kg−1 by the offline approach. In general, better recovery was achieved by use of online purification (for 72% of the analytes)
and the correlation between the two methods was good. The main advantages of the new online method are rapid and automated
sample pre-treatment, and reduction of sample manipulation, enabling high-throughput analysis and highly accurate results.
Because of all these characteristics, the proposed method is applicable and could be deemed necessary within the field of
food control and safety. 相似文献
16.
Authors developed a simple, sensitive, selective, rapid, rugged, and reproducible liquid chromatography–tandem mass spectrometry
method for the quantification of eletriptan (EP) in human plasma using naratriptan (NP) as an internal standard (IS). Chromatographic
separation was performed on Ascentis Express C18, 50 × 4.6 mm, 2.7 μm column. Mobile phase was composed of 0.1% formic acid:
methanol (40:60 v/v), with 0.5 mL/min flow rate. Drug and IS were extracted by liquid–liquid extraction. EP and NP were detected with proton
adducts at m/z 383.2→84.3 and 336.2→97.8 in multiple reaction monitoring (MRM) positive mode, respectively. The method was validated with
the correlation coefficients of (r
2) ≥ 0.9963 over a linear concentration range of 0.5–250.0 ng/mL. This method demonstrated intra- and inter-day precision within
1.4–9.2% and 4.4–5.5% and accuracy within 96.8–103% and 98.5–99.8% for EP. This method is successfully applied in the bioequivalence
study of 24 human volunteers. 相似文献
17.
A liquid chromatography–mass spectrometry (LC-MS) method was developed and validated for the simultaneous determination of
alisol A and alisol A 24-acetate from Alisma orientale (Sam.) Juz. in rat plasma using diazepam as an internal standard. A 200-μl plasma sample was extracted by methyl tert-butyl ether and the separation was performed on Kromasil C18 column (150 × 4.6 mm, 5 μm) with the mobile phase of acetonitrile (containing 0.1% of formic acid)–water (73:27, v/v) at a flow rate of 0.8 ml/min in a run time of 10 min. The two analytes were monitored with positive electrospray ionization
by selected ion monitoring mode. The lower limit of quantitation for both alisol A and alisol A 24-acetate were 10 ng/ml.
The calibration curves were linear in the measured range 10–1,000 ng/ml for alisol A and 10–500 ng/ml for alisol A 24-acetate.
The mean extraction recoveries were above 74.7% for alisol A and above 72.4% for alisol A 24-acetate from biological matrixes.
The intra- and inter-day precision for all concentrations of quality controls was lower than 14.1% (RSD %) for each analyte.
The accuracy ranged from −12.3% to 9.8% (RE %) for alisol A, and −8.6% to 14.2% (RE %) for alisol A 24-acetate. The method
was successfully applied to the study on the pharmacokinetics of alisol A and alisol A 24-acetate in rat plasma. 相似文献
18.
A new adsorbent is proposed for the solid-phase extraction of phenol and 1-naphthol from polluted water. The adsorbent (TX-SiO2) is an organosilica composite made from a bifunctional immobilized layer comprising a major fraction (91%) of hydrophilic
diol groups and minor fraction (9%) of the amphiphilic long-chain nonionic surfactant Triton X-100 (polyoxyethylated isooctylphenol)
(TX). Under static conditions phenol was quantitatively extracted onto TX-SiO2 in the form of a 4-nitrophenylazophenolate ion associate with cetyltrimethylammonium bromide. The capacity of TX-SiO2 for phenol is 2.4 mg g−1 with distribution coefficients up to 3.4 × 104 mL g−1; corresponding data for 1-naphthol are 1.5 mg g−1 and 3 × 103 mL g−1. The distribution coefficient does not change significantly for solution volumes of 0.025–0.5 L and adsorbent mass less than
0.03 g; 1–90 μg analyte can be easily eluted by 1–3 mL acetonitrile with an overall recovery of 98.2% and 78.3% for phenol
and 1-naphthol, respectively. Linear correlation between acetonitrile solution absorbance (A
540) and phenol concentration (C) in water was found according to the equation A
540 = (6 ± 1) × 10−2 + (0.9 ± 0.1)C (μmol L−1) with a detection range from 1 × 10−8 mol L−1 (0.9 μL g−1) to 2 × 10−7 mol L−1 (19 μL g−1), a limit of quantification of 1 μL g−1 (preconcentration factor 125), correlation coefficient of 0.936, and relative standard deviation of 2.5%. A solid-phase colorimetric
method was developed for quantitative determination of 1-naphthol on adsorbent phase using scanner technology and RGB numerical
analysis. The detection limit of 1-naphthol with this method is 6 μL g−1 while the quantification limit is 20 μL g−1. A test system was developed for naked eye monitoring of 1-naphthol impurities in water. The proposed test kit allows one
to observe changes in the adsorbent color when 1-naphthol concentration in water is 0.08–3.2 mL g−1. 相似文献
19.
Mazzucchelli I Rapetti M Fattore C Franco V Gatti G Perucca E 《Analytical and bioanalytical chemistry》2011,401(3):1013-1021
The development of a simple and rapid high-performance liquid chromatography (HPLC) method for the determination of the new
antiepileptic drug rufinamide (RFN) in human plasma and saliva is reported. Samples (250 μl) are alkalinized with ammonium
hydroxide (pH 9.25) and extracted with dichloromethane using metoclopramide as internal standard. Separation is achieved with
a Spherisorb silica column (250 × 4.6 mm i.d., 5 μm) at 30 °C using as mobile phase a solution of methanol/dichloromethane/n-hexane
10/25/65 (vol/vol/vol) mixed with 6 ml ammonium hydroxide. The instrument used was a Shimadzu LC-10Av chromatograph and flow
rate was 1.5 ml min-1, with a LaChrom L-7400 UV detector set at 230 nm. Calibration curves are linear [r
2 = 0.998 ± 0.002 for plasma (n = 10) and r
2 = 0.999 ± 0.001 for saliva (n = 9)] over the range of 0.25–20.0 μg ml-1, with a limit of quantification at 0.25 μg ml-1. Precision and accuracy are within current acceptability standards. The assay is suitable for pharmacokinetic studies in
humans and for therapeutic drug monitoring. 相似文献
20.
In the presence of carbonate and uranine, the chemiluminescent intensity from the reaction of luminol with hydrogen peroxide
was dramatically enhanced in a basic medium. Based on this fact and coupled with the technique of flow-injection analysis,
a highly sensitive method was developed for the determination of carbonate with a wide linear range. The method provided the
determination of carbonate with a wide linear range of 1.0 × 10−10–5.0 × 10−6 mol L−1 and a low detection limit (S/N = 3) of carbonate of 1.2 × 10−11 mol L−1. The average relative standard deviation for 1.0 × 10−9–9.0 × 10−7 mol L−1 of carbonate was 3.7% (n = 11). Combined with the wet oxidation of potassium persulfate, the method was applied to the simultaneous determination
of total inorganic carbon (TIC) and total organic carbon (TOC) in water. The linear ranges for TIC and TOC were 1.2 × 10−6–6.0 × 10−2 mg L−1 and 0.08–30 mg L−1 carbon, respectively. Recoveries of 97.4–106.4% for TIC and 96.0–98.5% for TOC were obtained by adding 5 or 50 mg L−1 of carbon to the water samples. The relative standard deviations (RSDs) were 2.6–4.8% for TIC and 4.6–6.6% for TOC (n = 5). The mechanism of the chemiluminescent reaction was also explored and a reasonable explanation about chemical energy
transfer from luminol to uranine was proposed.
Figure Chemiluminescence profiles in batch system. 1, Injection of 100 μL of K2CO3 into 1.0 mL luminol-1.0 mL H2O2 solution; 2-3 and 4-5, Injection in sequence of 100 μL of K2CO3 and 100 μL of uranine into 1.0 ml luminol-1.0 mL H2O2 solution; Cluminol = 1.0 × 10−7 mol/L, CH2O2 = 1.0 × 10−5 mol/L, Curanine = 1.0 × 10−5 mol/L, CK2CO3 = 1.0 × 10−7 mol/L except for 4-5 where CK2CO3 = 1.0 × 10−4 mol/L 相似文献