共查询到20条相似文献,搜索用时 62 毫秒
1.
Mahmure Ü. Özgür Güzin Alpdoğan Bürge Aşçi 《Monatshefte für Chemie / Chemical Monthly》2002,133(2):219-223
Summary. A simple and rapid derivative spectrophotometric assay procedure is described for the analysis of caffeine (1), acetaminophen (2), and propyphenazone (3) in tablet formulations. The concentration range of application is 5.0–25.0 μg·cm−3 for 2 and 3 and 1.0–5.0 μg·cm−3 for 1. The method involves the extraction of the drugs from tablets with 0.1 N H2SO4, filtration, appropriate dilution, and measurement of the fourth derivative absorbance values at zero crossing wavelengths
of 230.0, 263.2, and 256.6 nm for 1, 2, and 3. As a reference method, a reversed phase HPLC procedure was developed. Commercially available tablets were analyzed; statistical
comparison of the results with those obtained from the reference method showed good agreement. The derivative spectrophotometric
method has the advantage of being simple, rapid, inexpensive, and easy to perform.
Received April 18, 2001. Accepted (revised) June 5, 2001 相似文献
2.
Ming-Zhou Zhang Min-Zi Wang Zong-Lun Chen Jie-Hong Fang Mei-Ming Fang Jun Liu Xiao-Ping Yu 《Analytical and bioanalytical chemistry》2009,395(8):2591-2599
A multianalyte lateral-flow immunochromatographic technique using colloidal gold-labeled polyclonal antibodies was developed
for the rapid simultaneous detection of clenbuterol and ractopamine. The assay procedure could be accomplished within 5 min,
and the results of this qualitative one-step assay were evaluated visually according to whether test lines appeared or not.
When applied to the swine urines, the detection limit and the half maximal inhibitory concentration (IC50) of the test strip under an optical density scanner were calculated to be 0.1 ± 0.01 ng mL−1 and 0.1 ± 0.01 ng mL−1, 0.56 ± 0.08 ng mL−1, and 0.71 ± 0.06 ng mL−1, respectively, the cut-off levels with the naked eye of 1 ng mL−1 and 1 ng mL−1 for clenbuterol and ractopamine were observed. Parallel analysis of swine urine samples with clenbuterol and ractopamine
showed comparable results obtained from the multianalyte lateral-flow test strip and GC-MS. Therefore, the described multianalyte
lateral-flow test strip can be used as a reliable, rapid, and cost-effective on-site screening technique for the simultaneous
determination of clenbuterol and ractopamine residues in swine urine.
相似文献
3.
Cooper EM Covaci A van Nuijs AL Webster TF Stapleton HM 《Analytical and bioanalytical chemistry》2011,401(7):2123-2132
Organophosphate triesters tris(1,3-dichloro-2-propyl) phosphate (TDCPP) and triphenyl phosphate are widely used flame retardants
(FRs) present in many products common to human environments, yet understanding of human exposure and health effects of these
compounds is limited. Monitoring urinary metabolites as biomarkers of exposure can be a valuable aid for improving this understanding;
however, no previously published method exists for the analysis of the primary TDCPP metabolite, bis(1,3-dichloro-2-propyl)
phosphate (BDCPP), in human urine. Here, we present a method to extract the metabolites BDCPP and diphenyl phosphate (DPP)
in human urine using mixed-mode anion exchange solid phase extraction and mass-labeled internal standards with analysis by
atmospheric pressure chemical ionization liquid chromatography tandem mass spectrometry. The method detection limit was 8 pg mL−1 urine for BDCPP and 204 pg mL−1 for DPP. Recoveries of analytes spiked into urine ranged from 82 ± 10% to 91 ± 4% for BDCPP and from 72 ± 12% to 76 ± 8%
for DPP. Analysis of a small number of urine samples (n = 9) randomly collected from non-occupationally exposed adults revealed the presence of both BDCPP and DPP in all samples.
Non-normalized urinary concentrations ranged from 46–1,662 pg BDCPP mL−1 to 287–7,443 pg DPP mL−1, with geometric means of 147 pg BDCPP mL−1 and 1,074 pg DPP mL−1. Levels of DPP were higher than those of BDCPP in 89% of samples. The presented method is simple and sufficiently sensitive
to detect these FR metabolites in humans and may be applied to future studies to increase our understanding of exposure to
and potential health effects from FRs. 相似文献
4.
A rapid, ultra high-performance liquid chromatographic (UHPLC) method has been developed and validated for simultaneous identification
and analysis of the isoflavones genistein, daidzein, glycitin, puerarin, and biochanin A, and the flavonoids (±)-catechin,
(−)-epicatechin, rutin, hesperidin, neohesperidin, quercitrin, and hesperetin in human urine. Urine samples were incubated
with β-glucuronidase/sulfatase. UHPLC was performed with a Hypersil Gold (50 × 2.1 mm, 1.9 μm) analytical column. Elution
was with a gradient prepared from aqueous trifluoroacetic acid (0.05%) and acetonitrile. UV detection was performed at 254
and 280 nm. The calibration curves were indicative of good linearity (r
2 ≥ 0.9992) in the range of interest for each analyte. LODs ranged between 15.4 and 107.0 ng mL−1 and 3.9 and 20.4 ng mL−1 for flavonoids and isoflavones, respectively. Intra-day and inter-day precision (C.V., %) was less than 3.9% and 3.8%, respectively,
and accuracy was between 0.03% and 5.0%. Recovery was 70.35–96.58%. The method is very rapid, simple, and reliable, and suitable
for pharmacokinetic analysis. It can be routinely used for simultaneous determination of these five isoflavones and seven
flavonoids in human urine. The method can also be applied to studies after administration of pharmaceutical preparations containing
isoflavones and flavonoids to humans. 相似文献
5.
Natalia García-Otero Carmen Teijeiro-Valiño Jacobo Otero-Romaní Elena Peña-Vázquez Antonio Moreda-Piñeiro Pilar Bermejo-Barrera 《Analytical and bioanalytical chemistry》2009,395(4):1107-1115
Nickel(II) and lead(II) ionic imprinted 8-hydroxyquinoline polymers were synthesized by a precipitation polymerization technique
and were used as selective solid phase extraction supports for the determination of nickel and lead in seawater by flow injection
solid phase extraction on-line inductively coupled plasma-optical emission spectrometry. An optimum loading flow rate of 2.25 mL min−1 for 2 min and an elution flow rate of 2.25 mL min−1 for 1 min gave an enrichment factor of 15 for nickel. However, a low dynamic capacity and/or rate for adsorption and desorption
was found for lead ionic imprinted polymer and a flow rate of 3.00 mL min−1 for 4-min loading and a flow rate of 2.25 mL min−1 for 1-min elution gave a enrichment factor of 5. The limit of detection was 0.33 μg L−1 for nickel and 1.88 μg L−1 for lead, with a precision (n = 11) of 8% (2.37 μg Ni L−1) for nickel and 11% (8.38 μg Pb L−1) for lead. Accuracy was also assessed by analyzing SLEW-3 (estuarine water) and TM-24 (lake water) certified reference materials,
and the values determined were in good agreement with the certified concentrations. 相似文献
6.
A. Vonaparti E. Lyris I. Panderi M. Koupparis C. Georgakopoulos 《Analytical and bioanalytical chemistry》2009,395(5):1403-1410
In equine sport, salicylic acid is prohibited with a threshold level of 750 μg mL−1 in urine; hence, doping control laboratories have to establish quantitative and qualitative methods for its determination.
A simple and rapid liquid chromatographic/mass spectrometric method was developed and validated for the quantification and
identification of salicylic acid. Urine samples after 900-fold dilution and addition of the internal standard (4-methylsalicylic
acid) were directly injected to the liquid chromatography/quadrupole time-of-flight mass spectrometry system. Electrospray
ionization in negative mode with full scan acquisition mode and product ion scan mode were chosen for the quantification and
identification of salicylic acid, respectively. Run time was 2.0 min. The tested linear range was 2.5–50 μg mL−1 (after 100-fold sample dilution). The relative standard deviations of intra- and inter-assay analysis of salicylic acid in
horse urine were lower than 2.5% and 2.8%, respectively. Overall accuracy (relative percentage error) was less than 3.3%.
Method was applied to two real samples found to be positive for salicylic acid, demonstrating simplicity, accuracy, and selectivity. 相似文献
7.
Combined use of carbon nanotubes and ionic liquid to improve the determination of antidepressants in urine samples by liquid chromatography 总被引:1,自引:0,他引:1
Cruz-Vera M Lucena R Cárdenas S Valcárcel M 《Analytical and bioanalytical chemistry》2008,391(4):1139-1145
Antidepressants are widely used for the treatment of psychiatric disorders and therefore their monitoring in biological fluids
is quite important taking into account that they can produce dangerous biochemical imbalances in toxic doses. A method for
the determination of antidepressants in urine samples is presented using solid-phase extraction (SPE) and high-performance
liquid chromatography (HPLC) with ultraviolet (UV) detection. Home-made cartridges containing 30 mg multiwall carbon nanotubes
are employed for isolation of the analytes from the sample, allowing also the preconcentration of the analytes prior to the
HPLC analysis. Chromatographic separation was achieved in a reversed-phase C8 column using the ionic liquid 1-butyl-3-methylimidazolium trifluoromethanesulfonate as silanol activity suppressor, which
enhances peak symmetry and chromatographic resolution. Limits of detection were 12.3 ng mL−1 for trazodone and 90.1 ng mL−1 for fluoxetine. The repeatability of the proposed method expressed as RSD (n = 11) varied between 3.4% (fluoxetine) and 5.0% (desipramine and mianserine). Thus, the method is suitable for the therapeutic
monitoring of antidepressants in urine samples. 相似文献
8.
Raluca-Ioana Stefan-van Staden Jacobus F. van Staden Hassan Y. Aboul-Enein 《Journal of Solid State Electrochemistry》2010,14(6):997-1000
Three types of monocrystalline diamond: natural diamond 1 μm, synthetic diamond 50 μm (synthetic-1), and synthetic diamond
1 μm (synthetic-2) were used for the design of diamond paste electrodes for the determination of sildenafil citrate (Viagra)
using square wave voltammetry. The linear concentration ranges recorded for sildenafil citrate when natural diamond, synthetic-1,
and synthetic-2 based electrodes were used were between 10−12 and 10−8, 10−12 and 10−9, and 10−11 and 10−9 mol/L, respectively. Low detection limits which lie between 0.1 and 1 pmol/L proves the sensitivity of the electrodes. It
was found that sildenafil citrate yielded a peak at about +0.175 ± 0.025 V (versus Ag/AgCl) for all the electrodes. Sildenafil
citrate was determined with high reliability from its pharmaceutical formulation. 相似文献
9.
《Monatshefte für Chemie / Chemical Monthly》2002,19(1):219-223
A simple and rapid derivative spectrophotometric assay procedure is described for the analysis of caffeine (1), acetaminophen (2), and propyphenazone (3) in tablet formulations. The concentration range of application is 5.0–25.0 μg·cm−3 for 2 and 3 and 1.0–5.0 μg·cm−3 for 1. The method involves the extraction of the drugs from tablets with 0.1 N H2SO4, filtration, appropriate dilution, and measurement of the fourth derivative absorbance values at zero crossing wavelengths of 230.0, 263.2, and 256.6 nm for 1, 2, and 3. As a reference method, a reversed phase HPLC procedure was developed. Commercially available tablets were analyzed; statistical comparison of the results with those obtained from the reference method showed good agreement. The derivative spectrophotometric method has the advantage of being simple, rapid, inexpensive, and easy to perform. 相似文献
10.
Mahmoud Labib Martin Hedström Magdy Amin Bo Mattiasson 《Analytical and bioanalytical chemistry》2010,397(3):1217-1224
A novel technique for monitoring of low molecular mass analytes using a flow-injection capacitive biosensor is presented.
The method is based on the ability of a small molecular mass analyte to displace a large analyte–carrier conjugate from the
binding sites of an immobilized biorecognition element with weak affinity to both compounds. A model study was performed on
glucose as the small molecular mass analyte. In the absence of glucose, binding of a glucose polymer or a glycoconjugate to
concanavalin A results in a capacitance decrease. Upon introduction of glucose, it displaces a part of the bound glucose polymer
or glycoconjugate leading to a partial restoration of capacitance. Experimental results show that the change in capacitance
depends linearly on glucose concentration within the range from 1.0 × 10−5 to 1.0 × 10−1 M, corresponding to 1.8 μg ml−1 to 18 mg ml−1 in a logarithmic plot, with a detection limit of 1.0 × 10−6 (0.18 μg ml−1) under optimized conditions. In addition, by modifying the molecular mass of the glucose polymer, amount of biorecognition
element, and buffer composition, we were able to tune the analyte-sensing range. The developed technique has the benefits
of expanded dynamic range, high sensitivity, and excellent reusability. 相似文献
11.
Consuelo Cháfer-Pericás Ángel Maquieira Rosa Puchades Javier Miralles Amelia Moreno 《Analytical and bioanalytical chemistry》2010,396(2):911-921
An indirect competitive enzyme-linked immunosorbent assay (ELISA) was developed in plate to detect three sulfonamide residues
(sulfamerazine (SMR), sulfadimetoxine (SDM), and sulfadiazine (SDZ)) in gilthead sea bream (Sparus aurata) samples. Different extraction methodologies—using methanol/water 1:1 (v/v) + ethylene diamine tetraacetic acid (EDTA) 0.5% (m/v), acetonitrile, phosphate-buffered saline (PBS) 10 mmol L−1 pH 7 and acetate buffer 100 mmol L−1 pH 5—and cleanup steps, based on solid-phase extraction (C18, SCX, Si) or liquid extraction with hexane, were assayed. As optimum, a fast and simple method using acetonitrile was selected
to extract the sulfonamide residues from the edible muscle of fish. Due to matrix effects, a standard addition calibration
curve in fish extract is necessary for quantification purposes. Sulfonamide-free samples were spiked at different concentration
levels (between 30 and 90 ng g−1, 5–15 ng mL−1 in plate) and average recoveries (n = 8), ranging from 71% to 95%, 65% to 79%, and 72% to 95%, were obtained for SMR, SDM, and SDZ, respectively. The assay detection
limits for these antibiotics were lower than 100 μg kg−1 (maximum residue level established by the European Union). The accuracy was evaluated by spiking blank fish extracts at different
concentrations (10–40 ng mL−1, 5–20 ng mL−1 in plate), and the relative errors ranged between ±20%. Finally, in order to confirm the utility of the developed ELISA as
a screening methodology, fish samples from different supermarkets were analyzed, and results were compared with those obtained
by a validated high-performance liquid chromatography (HPLC) method. The correlation between the results obtained by both
ELISA and HPLC methods is satisfactory.
相似文献
12.
Ai-Lin Liu Jia-Dong Wang Wei Chen Xing-Hua Xia Yuan-Zhong Chen Xin-Hua Lin 《Journal of Solid State Electrochemistry》2012,16(4):1343-1351
A simple, rapid, sensitive, and accurate method for simultaneous electrochemical determination of procaine and its metabolite
(p-aminobenzoic acid, PABA) for pharmaceutical quality control and pharmacokinetic research was developed using a graphite paste
electrode. The differential pulse voltammetric results revealed that procaine and p-aminobenzoic acid, respectively, showed well-defined anodic oxidation peaks on a carbon paste electrode with a current peak
separation of 155 mV at a scan rate of 100 mV s−1. This well separation of the current peaks for these two compounds in voltammetry enables us to simultaneously determine
them. Good linearity (r > 0.998) between oxidation peak current and concentration was obtained in the range of 5.0 × 10−7–5.0 × 10−5 M for procaine and 5.0 × 10−7–2.0 × 10−5 M for PABA in pH 4.50 acetate buffer solution. The detection limit for both analytes is 5 × 10−8 M (S/N = 3:1). The present voltammetric method has been successfully used to determine trace p-aminobenzoic acid in procaine hydrochloride injection and procaine in plasma with a linear relationship of current to its
concentration ranging from 1.0 × 10−6 to 5.0 × 10−5 M (correlation coefficient of 0.9981) with a low detection limit of 5.0 × 10−7 M (S/N = 3:1). This validated method is promising to the study of pharmacokinetics in Sprague–Dawley rat and rabbit plasma after
an intravenous administration of procaine hydrochloride injection. 相似文献
13.
Luciana B. O. dos Santos Carlos M. C. Infante Jorge C. Masini 《Analytical and bioanalytical chemistry》2010,396(5):1897-1903
This work describes the development and optimization of a sequential injection method to automate the determination of paraquat
by square-wave voltammetry employing a hanging mercury drop electrode. Automation by sequential injection enhanced the sampling
throughput, improving the sensitivity and precision of the measurements as a consequence of the highly reproducible and efficient
conditions of mass transport of the analyte toward the electrode surface. For instance, 212 analyses can be made per hour
if the sample/standard solution is prepared off-line and the sequential injection system is used just to inject the solution
towards the flow cell. In-line sample conditioning reduces the sampling frequency to 44 h−1. Experiments were performed in 0.10 M NaCl, which was the carrier solution, using a frequency of 200 Hz, a pulse height of
25 mV, a potential step of 2 mV, and a flow rate of 100 μL s−1. For a concentration range between 0.010 and 0.25 mg L−1, the current (i
p, μA) read at the potential corresponding to the peak maximum fitted the following linear equation with the paraquat concentration
(mg L−1): i
p = (−20.5 ± 0.3)C
paraquat − (0.02 ± 0.03). The limits of detection and quantification were 2.0 and 7.0 μg L−1, respectively. The accuracy of the method was evaluated by recovery studies using spiked water samples that were also analyzed
by molecular absorption spectrophotometry after reduction of paraquat with sodium dithionite in an alkaline medium. No evidence
of statistically significant differences between the two methods was observed at the 95% confidence level. 相似文献
14.
Xiaolin Pei Qiuyan Wang Xiaofeng Qiu Longbin Ying Junhua Tao Tian Xie 《Applied biochemistry and biotechnology》2010,162(5):1423-1434
2-Deoxyribose-5-phosphate aldolase (DERA) catalyzes a sequential aldol reaction useful in synthetic chemistry. In this work,
the effect of a feeding strategy on the production of a thermophilic DERA was investigated in fed-batch cultures of recombinant
Escherichia coli BL21 (pET303-DERA008). The predetermined specific growth rate (μ
set) was evaluated at 0.20, 0.15, and 0.10 h−1, respectively. The DERA concentration and volumetric productivity were associated with μ
set. The cells synthesized the enzyme most efficiently at μ
set = 0.15 h−1. The maximum enzyme concentration (5.12 g/L) and total volumetric productivity (0.256 g L−1 h−1) obtained were over 10 and five times higher than that from traditional batch cultures. Furthermore, the acetate concentration
remained at a relatively low level, less than 0.4 g/L, under this condition which would not inhibit cell growth and target
protein expression. Thus, a specific growth rate control strategy has been successfully applied to induce fed-batch cultures
for the maximal production of the thermophilic 2-deoxyribose-5-phosphate aldolase. 相似文献
15.
An approach for rapid quantitation of 5-hydroxymethylfurfural (HMF) in honey using planar chromatography is suggested for
the first time. In high-performance thin-layer chromatography (HPTLC) the migration time is approximately 5 min. Detection
is performed by absorbance measurement at 290 nm. Polynomial calibration in the matrix over a range of 1:80 showed correlation
coefficients, r, of ≥ 0.9997 for peak areas and ≥ 0.9996 for peak heights. Repeatability in the matrix confirmed the suitability of HPTLC–UV
for quantitation of HMF in honey. The relative standard deviation (RSD, %, n = 6) of HMF at 10 ng/band was 2.9% (peak height) and 5.2% (peak area); it was 0.6% and 1.0%, respectively, at 100 ng/band.
Other possible detection modes, for example fluorescence measurement after post-chromatographic derivatization and mass spectrometric
detection, were also evaluated and can coupling can be used as an additional tool when it is necessary to confirm the results
of prior quantitation by HPTLC–UV. The confirmation is provided by monitoring the HMF sodium adduct [M + Na]+ at m/z 149 followed by quantitation in TIC or SIM mode. Detection limits for HPTLC–UV, HPTLC–MS (TIC), and HPTLC–MS (SIM) were 0.8 ng/band,
4 ng/band, and 0.9 ng/band, respectively. If 12 μL honey solution was applied to an HPTLC plate, the respective detection
limits for HMF in honey corresponded to 0.6 mg kg−1. Thus, the developed method was highly suitable for quantitation of HMF in honey at the strictest regulated level of 15 mg kg−1. Comparison of HPTLC–UV detection with HPTLC–MS showed findings were comparable, with a mean deviation of 5.1 mg kg−1 for quantitation in SIM mode and 6.1 mg kg−1 for quantitation in TIC mode. The mean deviation of the HPTLC method compared with the HPLC method was 0.9 mg kg-1 HMF in honey. Re-evaluation of the same HPTLC plate after one month showed a deviation of 0.5 mg kg−1 HMF in honey. It was demonstrated that the proposed HPTLC method is an effective method for HMF quantitation in honey.
相似文献
16.
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
17.
Qiong He Tian Gan Dongyun Zheng ShengShui Hu 《Journal of Solid State Electrochemistry》2010,14(6):1057-1064
Simple and sensitive electrochemical method for the determination of nitrite, based on a nano-alumina-modified glassy carbon
electrode (GCE), is described. Nitrite yields a well-defined oxidation peak whose potential is 0.74 V at the nano-alumina-coated
GCE in 0.1 mol L−1 phosphate buffer (pH 5.0). Compared with bare GCE, the nano-alumina-modified GCE has evident catalytic effect towards the
oxidation of nitrite, and its peak current can be significantly enhanced. Some of the experimental parameters were optimized
for the determination of nitrite. The oxidation peak current was proportional to nitrite concentration in the range of 5.0 × 10−8–1.1 × 10−3 mol L−1, and a detection limit of 1.0 × 10−8 mol L−1 was obtained. This method has been successfully used to the determination of nitrite in sausage sample. Furthermore, results
obtained by the method have been compared with spectrophotometric method. 相似文献
18.
Fosamprenavir is a pro-drug of the antiretroviral protease inhibitor amprenavir and is oxidizable at solid electrodes. The
anodic oxidation behavior of fosamprenavir was investigated using cyclic and linear sweep voltammetry at boron-doped diamond
and glassy carbon electrodes. In cyclic voltammetry, depending on pH values, fosamprenavir showed one sharp irreversible oxidation
peak or wave depending on the working electrode. The mechanism of the oxidation process was discussed. The voltammetric study
of some model compounds allowed elucidation of the possible oxidation mechanism of fosamprenavir. The aim of this study was
to determine fosamprenavir levels in pharmaceutical formulations and biological samples by means of electrochemical methods.
Using the sharp oxidation response, two voltammetric methods were described for the determination of fosamprenavir by differential
pulse and square-wave voltammetry at the boron-doped diamond and glassy carbon electrodes. These two voltammetric techniques
are 0.1 M H2SO4 and phosphate buffer at pH 2.0 which allow quantitation over a 4 × 10−6 to 8 × 10−5 M range using boron-doped diamond and a 1 × 10−5 to 1 × 10−4 M range using glassy carbon electrodes, respectively, in supporting electrolyte. All necessary validation parameters were
investigated and calculated. These methods were successfully applied for the analysis of fosamprenavir pharmaceutical dosage
forms, human serum and urine samples. The standard addition method was used in biological media using boron-doped diamond
electrode. No electroactive interferences from the tablet excipients or endogenous substances from biological material were
found. The results were statistically compared with those obtained through an established HPLC-UV technique; no significant
differences were found between the voltammetric and HPLC methods. 相似文献
19.
Leveriza F. Arenas Benilda S. Ebarvia Fortunato B. Sevilla III 《Analytical and bioanalytical chemistry》2010,397(7):3155-3158
A piezoelectric quartz crystal (PQC) sensor based on a molecularly imprinted polymer (MIP) has been developed for enantioselective
and quantitative analysis of d-(+)-methamphetamine (d(+)-MA). The sensor was produced by bulk polymerization and the resulting MIP was then coated on the
gold electrode of an AT-cut quartz crystal. Conditions such as volume of polymer coating, curing time, type of PQC, baseline
solvent, pH, and buffer type were found to affect the sensor response and were therefore optimized. The PQC-MIP gave a stable
response to different concentrations of d(+)-MA standard solutions (response time = 10 to 100 s) with good repeatability (RSD = 0.03
to 3.09%; n = 3), good reproducibility (RSD = 3.55%; n = 5), and good reversibility (RSD = 0.36%; n = 3). The linear range of the sensor covered five orders of magnitude of analyte concentration, ranging from 10−5 to 10−1 μg mL−1, and the limit of detection was calculated as 11.9 pg d(+)-MA mL−1
. The sensor had a highly enantioselective response to d(+)-MA compared with its response to l(−)-MA, racemic MA, and phentermine.
The developed sensor was validated by applying it to human urine samples from drug-free individuals spiked with standard d(+)-MA
and from a confirmed MA user. Use of the standard addition method (SAM) and samples spiked with d(+)-MA at levels ranging
from 1 × 10−3 to 1 × 10−2 μg mL−1 showed recovery was good (95.3 to 110.9%). 相似文献
20.
First results on Fe solid-phase extraction from coastal seawater using anatase TiO2 nano-particles 总被引:1,自引:0,他引:1
Christophe R. Quétel Emilia Vassileva Ivan Petrov Kristina Chakarova Konstantin I. Hadjiivanov 《Analytical and bioanalytical chemistry》2010,396(6):2349-2361
This paper describes the application of TiO2 nano-particles (anatase form) for the solid-phase extraction of iron from coastal seawater samples. We investigated the adsorption
processes by infra-red spectroscopy. We compared in batch and on-(mini)column extraction approaches (0.1 and 0.05 g TiO2 per sample, respectively), combined to external calibration and detection by inductively coupled plasma mass spectrometry
at medium mass resolution. Globally, this titania phase was slightly more efficient with seawater than with ultra-pure water,
although between pH 2 and pH 7, the Fe retention efficiency progressed more in ultra-pure water than in seawater (6.9 versus
4.8 times improvement). Different reaction schemes are proposed between Fe(III) species and the two main categories of titania
sites at pH 2 (adsorption of [FeL
x
](3 − x)+ via possibly the mediation of chlorides) and at pH 7 (adsorption of [Fe(OH)2]+ and precipitation of [Fe(OH)3]0). Under optimised conditions, the inlet system was pre-cleaned by pumping 6% HCl for ∼2 h, and the column was conditioned
by aspirating ultra-pure water (1.7 g min−1) and 0.05% ammonia (0.6 g min−1) for 1 min. Then 3 g seawater sample was loaded at the same flow rate while being mixed on-line with 0.05% ammonia at 0.6 g
min−1 to adjust the pH to 7. The iron retained on the oxide powder was then eluted with 3 g 6% HCl (<0.002% residual salinity in
the separated samples). The overall procedural blank was 220 ± 46 (2 s, n = 16) ng Fe kg−1 (the titania was renewed in the column every 20 samples, with 2-min rinsing in between samples with 6% HCl at 1.5 g min−1). The recovery estimated from the Canadian certified reference material CASS-2 was 69.5 ± 7.6% (2 s, n = 4). Typically, the relative combined uncertainty (k = 2) estimated for the measurement of ∼1 μg Fe kg−1 (0.45 μm filtered and acidified to pH 1.5) of seawater was ∼12%. We applied our method to a similar sample, from the coastal
region of the North Sea. The agreement well within stated uncertainties of our result with the value obtained independently
by isotope dilution mass spectrometry further validated our method. 相似文献