Ethyl Acetate-dichloromethane Research Articles

Towards realism in hazard assessment of plastic and rubber leachates – Methodological considerations

While plastic chemicals are key drivers of observed effects to aquatic species, there remains a lack of standardized and fit-for-purpose approaches for experimentally deconvoluting the effects of plastic chemicals from particle effects. This study investigated differences in chemical composition determined using two different organic solvents for extractions (dichloromethane-ethyl acetate, methanol) and by thermal desorption applied to 51 thermoplastic and elastomer products. The composition of natural water leachates of four select elastomers was also investigated. The number of chemical features in each material varied according to the extraction method, with solvent extracts exhibiting the most chemicals, and only 19 compounds commonly identified by all three methods. The number of chemical features in leachates was generally similar to the corresponding chemical extracts, but strong differences in relative composition were detected. While turbulence had minimal impact on leachate composition, particle loading strongly influenced leachate composition, temperature and salinity influenced the leachate concentration for some chemicals, and leaching time depended upon chemical mobility. Leachate composition cannot be readily predicted from particle characterization and multiple parameters are drivers of compositional variance in aquatic leachates. Recommendations for performing leaching studies that are relevant for hazard characterization in a realistic aquatic environment risk assessment scenario are suggested, with a particular focus on particle loading.

An Insight into In Vitro Antioxidant, Antimicrobial, Cytotoxic, and Apoptosis Induction Potential of Mangiferin, a Bioactive Compound Derived from Mangifera indica

Due to their low cost, toxicity, and health risks, medicinal plants have come to be seen as useful products and sources of biologically active compounds. Mangifera indica L., a medicinal plant with a long history, has a high bioactive metabolites content. Mangiferin (C19H18O11) is primary isolated from M. indica's leaves, which has many pharmacological benefits. In this investigation, ultrasonic-assisted extraction with ethanol as the extraction solvent was applied to obtain mangiferin from a local type of M. indica leaves. HPLC was performed after a dichloromethane-ethyl acetate liquid-liquid fractionation method. Further, UV-vis, FTIR, and NMR spectroscopy were utilized to elucidate the structure. Interestingly, purified mangiferin displayed promising antimicrobial efficacy against a diverse variety of fungal and bacterial pathogens with MICs of 1.95-62.5 and 1.95-31.25 µg/mL, respectively. Time-kill patterns also showed that mangiferin had both bactericidal and fungicidal action. Furthermore, it exhibited strong radical dosage-dependent scavenging activity (IC50 = 17.6 μg/mL) compared to vitamin C (Vc, IC50 = 11.9 μg/mL), suggesting it could be developed into a viable antioxidant agent. To our delight, the IC50 values of mangiferin for the MCF-7 and HeLa cell lines were 41.2 and 44.7 μg/mL, respectively, from MTT cell viability testing, and it was less harmful when tested against the noncancerous cell line. Notably, it significantly induced cell apoptosis in MCF-7 cells by 62.2-83.4% using annexin V-FITC/PI labeling. Hence, our findings suggest that mangiferin can be used in the medical industry to create therapeutic interventions and medication delivery systems for society.

Diversity and Biological Activities of Endophytic Fungi from the Flowers of the Medicinal Plant Vernonia anthelmintica.

Secondary metabolites produced by endophytic fungi are an important source of biologically active compounds. The current research was focused on the biological activities of ethyl acetate extracts of fungi, isolated and identified from Vernonia anthelmintica flowers for the first time. In addition, an investigation of the non-polar chemical composition of dichloromethane-ethyl acetate extracts of the most active fungal strain was carried out. The isolates included Ovatospora senegalensis NR-03, Chaetomium globosum NR-04, Thielavia subthermophila NR-06, Aspergillus calidoustus NR-10, Aspergillus keveii XJF-23 and Aspergillus terreus XJF-3 species. Strains were identified by 18S rRNA gene sequencing methods and were registered in GenBank. Crude extracts of the fungi displayed in vitro biological activities, including antimicrobial and cytotoxic activities. A melanin content assay was performed on murine B16 cells. An ethyl acetate extract of O. senegalensis NR-03 showed high anticancer and antimicrobial activity; therefore, we also studied the non-polar chemical composition of the dichloromethane-ethyl acetate fraction and identified 52 non-polar compounds with the different medium. This investigation discovered that the secondary metabolites of the total extract of endophytic fungi could be a potential source of alternative natural antimicrobial, cytotoxic and melanin synthesis activity in their host plant, and the isolation of bioactive metabolites may provide a lead to new compounds of pharmaceutical significance.

LC–MS/MS Method for Quantitation of Hydrochlorothia-zide and Nifedipine in Human Plasma

We have developed and validated a novel, sensitive, selective and reproducible reversed-phase high-performance liquid chromatography method coupled with electrospray ionization mass spectrometry (HPLC–ESI-MS/MS) for the simultaneous quantitation of hydrochlorothiazide (HCTZ) and nifedipine (NFP) from only 200 µL of human plasma. Diazepam (DZP) was used as an internal standard (IS). The analytes were extracted by a liquid-liquid extraction procedure with ethyl acetate-dichloromethane and separated on a reversed-phase Polaris 5 C18 Aanalytical column using a mobile phase composed of methanol containing 0.1% (v/v) formic acid and 5mM aqueous ammonium formate pH 6.0, delivered at a flow-rate of 300µL/min. Multiple reaction monitoring was performed in the negative ion mode using the transition m/z296.1→m/z205.2 (HCTZ), positive ion mode transitions m/z347.2→m/z 315.1 (NFP) and m/z285.0→m/z 193.2 (DZP) to quantify the drugs. Calibration curves in spiked plasma were linear (r2 ≥ 0.9953) from 5–2000 ng/mL for HCTZ and 5 – 400 ng/mL for NFP with a lower limit of quantification (LLOQ) of 5 ng/mL for both drugs. The intra- and inter- assay precisions (coefficient of variation) were less than 9% and the mean extraction recoveries were 98.1% (HCTZ), 99.5% (NFP) and 93.8% for the IS (DZP). The validated method was successfully applied to a limited population pharmacokinetics study of HCTZ and NFP among patients on hypertension care.

Crystal structures of four new iridium complexes, each containing a highly flexible carbodi-phos-phorane PCP pincer ligand.

Compound [Ir(C8H12)(C51H45P4)]Cl2 or [Ir(cod)(CH(dppm)2-κ3P,C,P)]Cl2 (1a), was obtained from [IrCl(cod)]2 and the carbodi-phospho-rane (CDP) salt [CH(dppm)2]Cl [where cod = cyclo-octa-1,5-diene and dppm = bis-(di-phenyl-phosphino)methane]. Treatment of 1a with thallium(I) tri-fluoro-methane-sulfonate [Tl(OTf)] and subsequent crystallization gave complex [Ir(C8H12)(C51H45P4)](OTf)2·CH3CO2C2H5·CH2Cl2 or [Ir(cod)(CH(dppm)2-κ3P,C,P)](OTf)2·CH3CO2C2H5·CH2Cl2 (1b) [systematic name: (cyclo-octa-1,5-diene)(1,1,3,3,5,5,7,7-octa-phenyl-1,7-diphospha-3,5-di-phospho-niaheptan-4-yl)iridium(I) bis-(tri-fluoro-methane-sulfonate)-ethyl acetate-di-chloro-methane (1/1/1)]. This five-coordinate iridium(I) complex cation adopts a trigonal-bipyramidal geometry with the CDP carbon and one cod double bond in axial sites. Compound 1b represents the first example of a non-meridional coordination of the PCP pincer ligand [CH(dppm)2]+ with a P-Ir-P angle of 98.08 (2)°. Compound 2, [IrCl2H(C51H44P4)]·(CH3)2CO or [IrCl2H(C(dppm)2-κ3P,C,P)]·(CH3)2CO [systematic name: di-chlorido-hydrido(1,1,3,3,5,5,7,7-octa-phenyl-1,5λ5,7-triphospha-3-phospho-niahept-4-en-4-yl)iridium(III) acetone monosolvate], crystallizes as an acetone monosolvate. It is a six-coordinate IrIII coordination compound. Here, the PCP pincer ligand is coordinated in a meridional manner; one chlorido ligand is positioned trans to the carbon donor, the remaining two coordination sites being occupied by the second chlorido and a hydrido ligand trans to each other. Complex 3, [IrCl2H(C51H45P4)]Cl·5H2O or [IrCl2H(CH(dppm)2-κ3P,C,P)]Cl·5H2O [systematic name: di-chlorido-hydrido(1,1,3,3,5,5,7,7-octa-phenyl-1,7-diphospha-3,5-di-phospho-niaheptan-4-yl)iridium(III) chloride penta-hydrate], represents the conjugate CH acid of 2. The ligand [CH(dppm)2]+ is coordinated in a meridional manner. In the cationic six-coordinate IrIII complex 4, [IrClH(CO)(C51H44P4)]Cl·2CH3OH·H2O or [IrClH(CO)(C(dppm)2-κ3P,C,P)]Cl·2CH3OH·H2O [systematic name: carbonyl-chlorido-hydrido(1,1,3,3,5,5,7,7-octa-phenyl-1,5λ5,7-triphospha-3-phos-pho-niahept-4-en-4-yl)iridium(III) chloride-methanol-water (1/2/1)], the chlorido ligand is found in the plane defined by the Ir center and the meridional PCP ligand; the H and CO ligands are positioned axially to this plane and trans to each other.

LC–MS/MS Method for Quantitation of Hydrochlorothia-zide and Nifedipine in Human Plasma

We have developed and validated a novel, sensitive, selective and reproducible reversed-phase high-performance liquid chromatography method coupled with electrospray ionization mass spectrometry (HPLC–ESI-MS/MS) for the simultaneous quantitation of hydrochlorothiazide (HCTZ) and nifedipine (NFP) from only 200 µL of human plasma. Diazepam (DZP) was used as an internal standard (IS). The analytes were extracted by a liquid-liquid extraction procedure with ethyl acetate-dichloromethane and separated on a reversed-phase Polaris 5 C18 Aanalytical column using a mobile phase composed of methanol containing 0.1% (v/v) formic acid and 5mM aqueous ammonium formate pH 6.0, delivered at a flow-rate of 300µL/min. Multiple reaction monitoring was performed in the negative ion mode using the transition m/z296.1→m/z205.2 (HCTZ), positive ion mode transitions m/z347.2→m/z 315.1 (NFP) and m/z285.0→m/z 193.2 (DZP) to quantify the drugs. Calibration curves in spiked plasma were linear (r2 ≥ 0.9953) from 5–2000 ng/mL for HCTZ and 5 – 400 ng/mL for NFP with a lower limit of quantification (LLOQ) of 5 ng/mL for both drugs. The intra- and inter- assay precisions (coefficient of variation) were less than 9% and the mean extraction recoveries were 98.1% (HCTZ), 99.5% (NFP) and 93.8% for the IS (DZP). The validated method was successfully applied to a limited population pharmacokinetics study of HCTZ and NFP among patients on hypertension care.

Thin-layer chromatographic fingerprinting of the nonvolatile fraction extracted from the medicinal herb Cistus incanus L.

ABSTRACTThe aim of this study was to provide the first from-start-to-end thin-layer chromatographic method of fingerprinting the Cistus incanus L. raw herbal material, with a purpose to further use it for rapid screening, authentication, and quality control of the traded C. incanus L. herbs. To this effect, 12 different C. incanus L. samples purchased as herbal teas from a local market were extracted by means of the accelerated solvent extraction (ASE) with chemometrically optimized solvent extraction mixture and temperature (methanol–water, 27:73, v/v; 130°C), to derive the polar fraction from the plant samples. Then, the extracts were developed in two thin-layer chromatographic systems, both using the commercially precoated silica gel 60 chromatographic plates, yet two different mobile phases (mobile phase 1, ethyl acetate–formic acid–acetic acid–water, 100:11:11:13, v/v/v/v, and mobile phase 2, ethyl acetate–dichloromethane–formic acid–acetic acid–water, 100:10:10:10:11, v/v/v/v/v). The chromatograms were densitometrically scanned in the reflectance mode at the wavelength λ = 366 nm to obtain fingerprints of the extracts derived from individual C. incanus L. samples. Mobile phase 2 performed slightly better, because with its use, the maximum number of 11 peaks could be seen in the respective fingerprints, whereas with mobile phase 1, the maximum number of 10 peaks only. Then an antioxidant potential of the investigated herbal extracts was assessed, making use of mobile phase 2 and the 0.20% methanol solution of 2,2-diphenyl picrylhydrazyl as a visualizing reagent. The resulting chromatograms were densitometrically scanned in the extinction mode at the wavelength λ = 550 nm to obtain biological fingerprints of the extracts. Finally, chromatographic and biological fingerprints underwent a semiquantitative evaluation in terms of the contents of the extracted polar fraction and an overall antioxidant potential of the individual plant species.

Comparison of the limits of detection and quantification of estradiol hemihydrate determined by thin-layer chromatography using different chromatographic conditions

ABSTRACTThin-layer chromatography (TLC) combined with densitometry was used to determine the limit of detection (LOD) and quantification (LOQ) of estradiol hemihydrate. Average values of both LOD and also LOQ were determined on the basis of the standard deviation of the response and slope of special calibration curve in accordance with the procedure required by validation guidelines. Influence of chromatographic conditions, such as different sorbents and various mobile-phase compositions on determining of LODs and LOQs of examined steroid by normal phase TLC (NP-TLC) and reversed-phase (RP-TLC) techniques, was estimated. Of all chromatographic plates and mobile phases used, those that gave the best results (the lowest LOD and LOQ value) using NP-TLC system are silica gel 60 F254 plates developed with mobile phase consisted of dichloromethane–ethyl acetate (8:2, v/v). In the case of RP-TLC method, a mixture of methanol–water (9:1, v/v) as mobile phase enabled detection of estradiol hemihydrate at the lowest concentration level on RP8 F254s precoated plates. The results of LODs and LOQs obtained in this study confirm that the proposed TLC-densitometric method is suitable for the quantification of estradiol hemihydrate in the samples containing this steroid in the range of 0.093–3.930 µg spot−1. The described method could be an important tool in pharmaceutical as well as in clinical or environmental analysis of examined steroid hormone.

Isolation and identification of a new neo-clerodane diterpenoid from Teucrium chamaedrys L.

Teucrium chamaedrys L. is an aromatic and medicinal plant used as traditional medicine. Aerial parts of the plant material were dried and extracted with hexane–dichloromethane (extract 1), ethyl acetate–dichloromethane (extract 2) and methanol–dichloromethane (extract 3) in a ratio of 1:1 at rt successively. The solvents were evaporated to give crude extracts. Extract 1 was suspended in water at 60°C then partitioned successively with hexane and ethyl acetate to give hexane and ethyl acetate portions. After the column chromatography (silica gel) of ethyl acetate extract, one new and four known compounds were isolated. The new compound was named as 1(12S,18R)-15,16-epoxy-2β,6β-dihydroxy-neo-cleroda-13(16),14-dien-20,l2-olide-l8,l9-hemiacetal (teuchamaedryn D) (4). The known compounds were teucrin A (1), dihydroteugin (2), teucroxide (3), syspirensin A (5). The chromatographic methods were also applied for extract 3 to isolate verbascoside (6) and teucrioside (7). The structure of isolated compounds was elucidated by spectroscopic methods including LC-TOF/MS, 1D NMR and 2D NMR.

Identificación de flavonoles en un extracto polar de Aciotis polystachya (Bonpland) Triana (Melastomataceae)

Objetive : To isolate, to identify and to elucidate the secondary metabolites present in the same fraction extract ethyl acetate of air parts of Aciotis polystachya (Bonplan) Triana (Melastomataceae). Methodology : Techniques using column chromatography, thin layer chromatography and preparative chromatography was isolate, identify and purify secondary metabolites, the analysis of the spectra of 1 H-NMR, 13 C-NMR and two-dimensional NMR techniques ( 1 H- 1 H COSY and HMQC) allowed us to elucidate the chemical structure of these metabolites. Results : The methanol extract was performed Aciotis polystachya solid to liquid extraction with ethyl acetate, fractions 57-64 from the chromatography of the extract usually ethyl acetate, eluted with solvent dichloromethane-ethyl acetate in volumetric proportions 40-60%, 0.03 grams was isolated as a yellow solid after successive chromatographies, similarly fractions 65-73 and 57-64 from the same chromatography was obtained 0.13 grams of total product as yellow crystals. Conclusions : Quercetin and Kaempherol are new secondary metabolites report both gender as this species, and are responsible for many biological and pharmacological activities, which justify some ethnobotanical uses of this plant.

A sensitive and selective liquid chromatography−tandem mass spectrometry method for simultaneous determination of five isoquinoline alkaloids from Chelidonium majus L. in rat plasma and its application to a pharmacokinetic study

Chelidonium majus L. is one of the most important medicinal plants of the family Papaveraceae. Its pharmacological effects have been primarily attributed to the presence of a number of alkaloids. In the present study, a sensitive and selective liquid chromatography-tandem mass spectrometry method for simultaneous determination of five isoquinoline alkaloids from Chelidonium majus L. was developed and validated. The analytes (protopine, chelidonine, coptisine, sanguinarine and chelerythrine), together with the internal standard (palmatine), were extracted from acidified rat plasma with ethyl acetate-dichloromethane (4:1, v/v). Chromatographic separation was carried out on a Diamonsil C(18) column with an isocratic mobile phase consisting of acetonitrile and water (adjusted to pH 2.3 with formic acid) (30:70, v/v) at a flow rate of 0.4 ml/min. Mass spectrometric detection was performed by selected reaction monitoring mode via electrospray ionization source operating in positive ionization mode. The assay exhibited good linearity (r ≥ 0.9933) for all the analytes. The lower limits of quantification were 0.197-1.27 ng/ml using only 50 µl of plasma sample. The intra- and inter-day precisions were less than 11.9%, and the accuracy was between -6.3% and 9.3%. The method was successfully applied to the pharmacokinetic study of the five alkaloids in rats after intragastric administration of Chelidonium majus L. extract.

Determination of chlorpyrifos’ main metabolite 3,5,6-trichloro-2-pyridinol in human urine by ultra performance liquid chromatography coupled with tandem mass spectrometry

A method for the determination of 3,5,6-trichloro-2-pyridinol (3,5,6-TCP) in human urine, which is the main metabolite of chlorpyrifos, has been established employing ultra performance liquid chromatography coupled with tandem mass spectrometry (UPLC-MS/ MS). The urine samples were prepared by liquid-liquid extraction with dichloromethane-ethyl acetate (20: 80, v/v) solution followed by the separation with the gradient elution of acetonitrile-water on an ACQUITY UPLC BEH C18 column. The analyte was detected by tandem mass spectrometry under the negative ion mode with the electrospray ionization (ESI) source and the selective ion recording (SIR) mode. Under the optimized conditions, the calibration curve was linear in the range of 0.005 -0.4 mg/L. The limit of detection was 0.41 microg/L. The average recovery was 97.9%. The intra- and inter-day precisions calculated with RSDs were all within 15% at each quality control (QC) level. The developed method is simple, sensitive, accurate and repeatable, which has been successfully applied to determine the exposure level of 3,5,6-TCP in the real samples of human urine. The results show that this method is supportive for the exposure assessment in human health risk analysis and monitoring the biological burden of chlorpyrifos.

Development and Validation of a HPLC-UV Method for Simultaneous Determination of Five Sulfonylurea Herbicide Residues in Groundnut Oil Followed by Matrix Solid-Phase Dispersion

A simple, sensitive, and inexpensive method was developed using matrix solid-phase dispersion (MSPD), together with high performance liquid chromatographic method for determination of sulfonylurea herbicide residues (nicosulfuron, pyrazosulfuron ethyl, metsulfuron methyl, chlorsulfuron and azimsulfuron) in groundnut oil. The evaluated parameters included the type and amount of sorbent (silica gel, C 18 and florisil) and the nature of eluent (ethyl acetate, dichloromethane, and acetonitrile). The best results were obtained using 1.0 g of groundnut oil sample, 1.0 g of C 18 as sorbent, and 20 mL of ethyl acetate-dichloromethane (1 : 1, (v/v)). The method was validated using groundnut oil samples spiked with sulfonylurea herbicides at different concentration levels (0.05 and 0.5 g/mL). Average recoveries (using each concentration six replicates) ranged 90–97%, with relative standard deviations less than 3%, the concentration of calibration solutions was in the range 0.01–2.0 g/mL and limits of detection (LOD) as well as limits of quantification (LOQ) were 0.01 g/mL and 0.05 g/mL, respectively.

Determination of SYUIQ-F5, a Novel Telomerase Inhibitor and Anti-tumor Lead-Compound, in Tissues and Plasma Samples by LC–MS–MS: Application to a Tissue Distribution Study in Rat

A sensitive assay for determining SYUIQ-F5, a novel telomerase inhibitor and anti-tumor drug, in rat tissues and plasma was developed and validated by using liquid chromatography/tandem mass spectrometry (LC–MS–MS). After a single step liquid–liquid extraction with ethyl acetate-dichloromethane, SYUIQ-F5 and SUCL (internal standard) were subjected to LC–MS–MS analysis using positive electro-spray ionization under selected reaction monitoring mode. Chromatographic separation of SYUIQ-F5 and SUCL was achieved on a Zorbax Eclipse Plus C18 column (I.D. 4.6 mm × 150 mm, 3.5 μm) with a mobile phase consisting of acetonitrile-2 mM ammonium formate (90:10, v/v) at a flow rate of 0.6 mL min−1. The intra- and inter-batch precision of the method were liver> lung> spleen> stomach> kidneys> heart> brain> muscle> fat> testes> plasma. SYUIQ-F5 could still be detected in most of the tissues at 48-h post-dosing. These results indicated that the LC–MS–MS method was sensitive, reliable, and specific to quantify SYUIQ-F5 in different rat tissues.

Anti-Typhoid Properties of <i>Phyllanthus Amarus</i> Extracts

Phyllanthus amarus is a medicinal plant belonging to the family Euphorbiaceae and commonly known as ‘carry-me-seed’ or quinine weed. The whole plant was subjected to solvent extractions using petroleum ether and ethanol. Both crude extracts were tested for antimicrobial activity against Salmonella typhi using agar well-diffusion method of sensitivity testing. The crude etha-nolic extract showed good inhibitory effect against the bacteria but the petroleum ether extract showed no activity. The crude ethanol extract was subjected to column chromatographic separa-tion using dichloromethane: ethyl acetate (DCM/EA) solvent system. The column was finally eluted with methanol. The fractions eluted from the column were tested against the Salmonella typhi. The organism was sensitive to the methanol fractions at different concentrations (4.37mg/ml, 8.75mg/ml, 17.50mg/ml, 35.00mg/ml and 70.00mg/ml) with a zone of inhibition of 8mm, 12mm, 16mm, 20mm, and 22mm respectively. The Salmonella typhi was insensitive to the DCM/EA fractions. Phytochemical screening tests performed on the crude ethanolic extract revealed the presence of alkaloids, steroids, saponins, lignans, tannins and flavonoids.

A Matrix Solid-Phase Dispersion Method for the Extraction of Seven Pesticides from Mango and Papaya

A simple and effective extraction method based on matrix solid-phase dispersion was developed to determine trichlorfon, pyrimethanil, methyl parathion, tetraconazole, thiabendazole, imazalil, and tebuconazole in papaya and mango using gas chromatography-mass spectrometry with selected ion monitoring. Different parameters of the method were evaluated, such as type of solid-phase (silica-gel, neutral alumina, and Florisil), the amount of solid-phase, and eluent [dichloromethane, ethyl acetate-dichloromethane (4:1, 1:4, 1:1, 2:3, v/v)]. The best results were obtained using 2.0 g of mango or papaya, 3.0 g of silica as dispersant sorbent, and ethyl acetate-dichloromethane (1:1, v/v) as eluting solvent. The method was validated using mango and papaya samples fortified with pesticides at different concentration levels (0.05, 0.10, and 1.0 mg/kg). Average recoveries (4 replicates) ranged from 80% to 146%, with relative standard deviations between 1.0% and 28%. Detection and quantification limits for mango and papaya ranged from 0.01 to 0.03 mg/kg and 0.05 to 0.10 mg/kg, respectively. The proposed method was applied to the analysis of these compounds in commercial fruit samples from a local market (Aracaju/SE, Brazil), and residues of the pesticides were not detected on the samples.

Determination of olprinone in human plasma utilizing liquid chromatography tandem mass spectrometry

A sensitive and rapid method was developed for quantification of olprinone in human plasma utilizing liquid chromatography tandem mass spectrometry (LC–MS/MS). An aliquot of 1 mL plasma sample was extracted with ethyl acetate–dichloromethane. Separation of olprinone and the milrinone (internal standard, IS) from the interferences was achieved on a C 18 column followed by MS/MS detection. The analytes were monitored in the positive ionization mode. Multiple reaction monitoring using the transition of m/ z 251 → m/ z 155 and m/ z 212 → m/ z 140 was performed to quantify olprinone and IS, respectively. The method had a total chromatographic run time of 3 min and linear calibration curves over the concentration range of 0.5–60 ng/mL. The lower limit of quantification (LLOQ) was 0.5 ng/mL. The intra- and inter-day precisions were less than 16.3% for low QC level, and 7.1% for other QC levels, respectively. The intra- and inter-day relative errors were ranged between −12.2% and 3.7% for three QC concentration levels. The validated method was successfully applied to the quantification of olprinone concentration in human plasma after intravenous (i.v.) administration of olprinone at a constant rate of infusion of 2 μg/(kg min) for 5 min in order to evaluate the pharmacokinetics.

Miniaturized Method Based on Matrix Solid-Phase Dispersion for the Rapid Screening of 36 Pesticides in Agricultural Food Commodities

Matrix solid-phase dispersion and gas chromatography-mass spectrometry were used for the rapid screening of 36 pesticides in agricultural products. Homogenized sample (0.5 g), C8-modified silica (0.5 g) and Na2SO4 (1 g) were mixed and transferred to a cartridge containing activated silica (0.5 g). Best recoveries (>60%) were found using dichloromethane-ethyl acetate (4:1) for elution. Analytical characteristics at spiking levels (10–100 μg/kg) were calculated for each pesticide. Matrix effects were studied by comparing the slopes of the matrix-matched calibration curves. Fruit and vegetable samples from South Africa complied with EU and South African current regulation, except for cypermethrin in green beans.

Densitometric HPTLC method for analysis of triterpenoids in the leaves ofJovibarba sobolifera(Sims.) Opiz (Hen and Chickens Houseleek)

Summary High performance thin-layer chromatography (HPTLC) combined with densitometry has been used for analysis of the triterpenoid content of acetone and ethyl acetate extracts of the leaves of Jovibarba sobolifera (Sims.) Opiz. After optimization of the extraction process, HPTLC separation was successfully standardized, using silica gel plates washed with methanol and dichloromethane, dichloromethane–ethyl acetate 18.5:1.5 as mobile phase, and 8% H2SO4 in ethanol (m/m) as spray reagent. Triterpenoids in the leaves of Jovibarba sobolifera were quantified by measurement of absorbance. Three spots were observed on chromatograms – the sum of α and β-amyrin, oleanolic acid, and an unidentified compound. All of the triterpenoid components were analyzed for the first time in this plant. The triterpenoid content was calculated statistically.

Multiresidue analysis of atrazine, diuron and their degradation products in sewage sludge by liquid chromatography tandem mass spectrometry

A multiresidue method has been developed to analyze atrazine (ATZ), diuron (DIU), and their major degradation products, desethylatrazine (DEA), desisopropylatrazine (DIA), and dichlorophenylmethylurea in sewage sludge. Liquid chromatography coupled to electrospray tandem mass spectrometry (LC-ESI-MS-MS) allowed, in the multiple-reaction monitoring mode, the simultaneous analysis of these pesticides in only one run after their extraction with ethyl acetate-dichloromethane 90:10 (v/v) and a cleanup on a Florisil column. Stable isotopically labeled ATZ and DIU were used as internal standards to overcome matrix effects during the pesticide quantification. Using fortified samples, the method gave rise to 86-115% as mean recovery values depending on the analyte. Limits of detection (LODs) and of quantification (LOQs) ranging from 0.3 (DIA) to 1.5 (DEA) microg kg(-1) dw and from 0.4 (DIA) to 2.0 (DEA) microg kg(-1) dw, respectively, were sufficient to achieve the monitoring of these molecules in sludge from wastewater treatment plants of the Ile-de-France region.