scholarly journals Synthesis of functionalized by an oxime group surfactants on the basis of imidazole, pyridine and alkylamines

2019 ◽  
Vol 85 (8) ◽  
pp. 94-105
Author(s):  
Alexander Shumeiko ◽  
Michael Kostrikin ◽  
Ilya Kapitanov ◽  
Anna Serdyuk ◽  
Nikolay Burakov ◽  
...  
Keyword(s):  
Thin Layer ◽  
Solid Phase ◽  
Internal Standard ◽  
Direct Interaction ◽  
Head Group ◽  
Oxime Group ◽  
Alkyl Radicals ◽  
Phase Liquid ◽  
Composition Structure ◽  
Dimeric Surfactants

Methods have been developed for the synthe-sis of a series of monomeric and dimeric surfactants functionalized by an oxime group based on imid-azole, pyridine and alkylamines. Alkyl radicals of varying degrees of branching were used, both as sub-stituents at the nitrogen atom of the head group and as spacers in the formation of dimeric products. This allowed to create a whole spectrum of supramo-lecular systems with different physicochemical pro-perties and reactivity.Methods of obtaining a number of intermedi-ate products were improved, primarily for the reac-tion of the imidazole alkylation using interphase ca-talysis conditons — solid phase-liquid. The method of obtaining surfactants based on imidazole consisted in the interaction of alkylimidazoles with chloro-acetaloxime in a suitable solvent or with chloro-acetone and subsequent reaction with a hydroxyla-mine solution. In the preparation of pyridine-based surfactants, the corresponding oxo-substituted pyri-dine was reacted with a hydroxylamine solution, fol-lowed by reaction of the obtained product with al-kyl halide. A method has been developed for the syn-thesis of functionalized surfactants based on alipha-tic amines, where for monomeric products a path is chosen that is associated with the sequential alkyla-tion of 1-chloroacetoxime with dimethylamine and dodecyl bromide, and for dimeric ones, the direct interaction of 1,3-dichloroacetoxime with 1,1-dime-thyl-1-dodecylamine.The composition, structure and purity of the obtained compounds were confirmed by NMR spec-troscopy, thin-layer chromatography and elemental analysis. NMR spectra were recorded on a BRUKER Avance II 400 instrument (400 MHz), TMS was used as an internal standard. Chromatography in a thin layer of silica gel was performed on Merck Si-licaGel 60 F254 plates (eluent — chloroform: meth-anol = 10:1).The data presented by us testify to the pro-spects of the chosen pathway for structural modifica-tion of surfactants functionalized by the oxime group, and give direction for the further design of such microheterogeneous systems.

Quantitation of Sulfamethazine in Pork Tissue by Thin-Layer Chromatography

1993 ◽  
Vol 76 (2) ◽  
pp. 335-341 ◽  
Author(s):  
Joseph Unruh ◽  
Daniel P Schwartz ◽  
Robert A Barford
Keyword(s):  
Thin Layer ◽  
Limit Of Detection ◽  
Solid Phase ◽  
Signal To Noise Ratio ◽  
Internal Standard ◽  
Signal To Noise ◽  
Thin Layer Chromatographic Plate ◽  
Average Accuracy ◽  
Chromatographic Plate ◽  
Layer Chromatography

Abstract Our earlier method to detect and quantitate sulfamethazine (SMZ) in milk at the 10 ppb level was modified to quantitate SMZ in pork tissue. Sulfabromomethazine (SBZ) is added to the tissue as an internal standard. SMZ and SBZ are extracted from the tissue into water as the supernatant of a centrifuged, aqueous homogenate and are cleaned up and concentrated by a series of solid-phase extractions. The sulfonamide-containing eluate is then separated on a silica gel thin-layer chromatographic plate. SBZ and SMZ are derivatized with fluorescamine, and their fluorescence is quantitated with a scanning densitometer. The limit of detection was estimated at 0.25 ppb (signal-to-noise ratio, 3:1). The average accuracy over the analysis range (0.54-21.8 ppb [μg/kg]) was 95.6% (standard deviation = 29.4%, n = 54).

Simultaneous Assay of Corticosterone and Cortisol in Plasma by Reversed-Phase Liquid Chromatography

1992 ◽  
Vol 38 (3) ◽  
pp. 346-352 ◽  
Author(s):  
M Hariharan ◽  
S Naga ◽  
T VanNoord ◽  
E K Kindt
Keyword(s):  
Extraction Method ◽  
Solid Phase ◽  
Internal Standard ◽  
Reversed Phase ◽  
Reversed Phase Liquid Chromatography ◽  
Ultraviolet Detector ◽  
Liquid Chromatographic Method ◽  
Analytical Recovery ◽  
Phase Liquid ◽  
Liquid Chromatographic

Abstract We have developed a simple, specific, and sensitive reversed-phase liquid-chromatographic method for accurate and simultaneous analysis of corticosterone and cortisol in human plasma. We achieved a detection limit of 300 ng/L for both steroids by modifying the old solid-phase extraction method to make use of "Tef Elutor" C18 columns, using a minibore (100 x 2 mm) analytical column, and using an ultraviolet detector with a 10-mm-pathlength flow cell. With the new extraction method absolute extraction efficiencies were greater than 90% for all the analytes, including the internal standard, flumethasone. The mobile phase was water (containing 5 mL of triethylamine per liter and citric acid to adjust the pH to 6.5), tetrahydrofuran, and acetonitrile (82/10/8 by vol). The average interassay CV for corticosterone at 0-25 micrograms/L was 6.5%; that for cortisol at 0-300 micrograms/L was 3.8%. The analytical recovery relative to the internal standard was 100.2% for cortisol and 102.6% for corticosterone. Possible interferences from drugs and other steroids were studied.

Analysis of 5-Vinyl-l,3-Oxazolidine-2-Thione by Liquid Chromatography

1992 ◽  
Vol 75 (3) ◽  
pp. 529-536 ◽  
Author(s):  
Alain Quinsac ◽  
Daniel Ribaillier ◽  
Patrick Rollin ◽  
Michel Dreux
Keyword(s):  
Liquid Chromatography ◽  
Solid Phase ◽  
Internal Standard ◽  
Rapeseed Meal ◽  
Reversed Phase ◽  
Mercury Acetate ◽  
Phase Liquid ◽  
Biological Environment ◽  
Liquid Chromatographic

Abstract 5-Vlnyl-1,3-oxazolldlne-2-thlone (5-VOT) Is a goltrlgenlc compound released by enzymatic degradation of progoltrln, the major glucoslnolate occurring In rapeseed meal. A liquid chromatographic (LC) method for determination of 5-VOT in a biological environment Is presented. Complete extraction of 5-VOT has been carried out by complexatlon with phenyl mercury acetate under cyclohexanlc conditions, and then by decomplexation using an aqueous sodium thlosulfate solution. These reactions displace 5-VOT from an aqueous to an organic medium, and then back again to the aqueous condition, thus assuring high selectivity of the extraction. Precise quantitation of 5-VOT Is completed in 10 mln by reversed-phase liquid chromatography using an isocratic elutlon with UV detection and a specially made synthetic Internal standard. Concentration steps by solid-phase chromatography and evaporation can be introduced In the analytic procedure to lower the detection limit of 5-VOT in the sample used from 100 to 0.5 ppb. Using sow milk samples, the method was tested by small measured additions of 5-VOT. The recovery rate of the product was very good (>97%). Different phases used to achieve a sensitive, rapid, and precise method are described.

Bioanalytical method development and validation of simultaneous analysis of telmisartan and hydrochlorthiazide in human plasma using LC-MS/MS

2016 ◽  
Vol 5 (03) ◽  
pp. 4862 ◽  
Author(s):  
Mathew George* ◽  
Lincy Joseph ◽  
Arpit Kumar Jain ◽  
Anju V.
Keyword(s):  
Human Plasma ◽  
Retention Time ◽  
High Performance ◽  
Method Development ◽  
Matrix Effects ◽  
Solid Phase ◽  
Internal Standard ◽  
Assay Method ◽  
Buffer System ◽  
Internal Standards

A simple, sensitive, rapid and economic high performance thin layer chromatographic method and a mass spectroscopic assay method has been developed for the quantification of telmisartan and hydrochlorthiazide combination in human plasma. The internal standards and analytes were extracted from human plasma by solid-phase extraction with HLB Oasis1cc (30mg) catridges. The scanning and optimization for the samples are done using methanol: water (50:50). The samples were chromatographed using reverse phase chromatography with C-18 column of different manufacturers like Ascentis C18 (150×4. 6, 5µ) using the buffer system Acetonitrile: Buffer (80:20%v/v) which consist of 2±0. 1Mm ammonium format at a flow rate of 0. 7ml/min at a column oven temperature 35±10c. The internal standard used was hydrochlorthiazide13c1, d2 and telmisartand3. The extraction techniques include conditioning, loading, washing and elution, drying followed by reconstitution of the dried samples. The volume injected was 10µl with the retention time of 3-4 min for telmisartan, 1-2 min for hydrochlorthiazide and for the internal standards the retention time was 3-4 min for telmisartand3 and 1-2 min for hydrochlorthiazide c13d2. The rinsing solution was Acetonitrile: HPLC grade water in the ratio (50:50). The above developed method was validated using various parameters like selectivity and sensitivity, accuracy and precision, matrix effects, % recovery and various stability studies. The method was proved to be sensitive, accurate, precise and reproducible. The preparation showed high recovery for the quantitative determination of telmisartan and hydrochlorthiazide in human plasma.

A solid-phase extraction method that eliminates matrix effects of complex pulp mill effluents for the analysis of lipophilic wood extractives

2020 ◽  
Vol 35 (4) ◽  
pp. 577-588
Author(s):  
Sebastian España Orozco ◽  
Philipp Zeitlinger ◽  
Karin Fackler ◽  
Robert H. Bischof ◽  
Antje Potthast
Keyword(s):  
Solid Phase Extraction ◽  
Matrix Effects ◽  
Solid Phase ◽  
Internal Standard ◽  
Pulp Mill ◽  
Phase Extraction ◽  
Wood Extractives ◽  
Wood Extractive ◽  
Pulp Mill Effluents ◽  
The Impact

AbstractThe extraction of lipophilic wood extractives from pulp and paper process waters proves to be a challenging task, due to harsh and alternating process and sample conditions. This study has determined the potential use of polymeric sorbents for solid-phase extraction (SPE) and compared to classical silica-based reversed-phase packed columns, with polymeric hydrophilic-lipophilic balanced (HLB) cartridges being the sorbent with the most potential. Recovery functions were obtained with an internal standard mixture representative for the main lipophilic wood extractive groups, which are fatty acids and alcohols, sterols, sterol esters and triglycerides. The impact of pH, sample volume and sample matrix, expressed as TOC and cations, on the retention behavior of lipophilic extractives during SPE of industrial samples were determined with polymeric HLB sorbent. High variations in the composition of pulp mill matrices led to different optimal extraction conditions. Thus, a new SPE protocol was developed, which bypasses matrix interferences and omits the loss of analytes due to sample preparation. The method is applicable to different pulp mill effluents with large discrepancies in pH and sample matrices, resulting in recoveries >90 % with RSD <5 % for all lipophilic wood extractives.

scholarly journals Investigations on the Key Odorants Contributing to the Aroma of Children Soy Sauce by Molecular Sensory Science Approaches

Foods ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1492
Author(s):  
Jia Huang ◽  
Haitao Chen ◽  
Zhiming Zhang ◽  
Yuping Liu ◽  
Binshan Liu ◽  
...  
Keyword(s):  
Gas Chromatography ◽  
Solid Phase ◽  
Internal Standard ◽  
Retention Indices ◽  
Soy Sauce ◽  
Gas Chromatography Mass Spectrometry ◽  
Volatile Components ◽  
Active Compounds ◽  
Standard Curve ◽  
Key Odorants

To investigate the key odor-active compounds in children’s soy sauce (CSS), volatile components were extracted by means of solvent extraction coupled with solvent-assisted flavor evaporation (SE-SAFE) and solid-phase microextraction (SPME). Using gas chromatography-olfactometry (GC-O) and gas chromatography-mass spectrometry (GC-MS), we identified a total of 55 odor-active compounds in six CSSs by comparing the odor characteristics, MS data, and retention indices with those of authentic compounds. Applying aroma extract dilution analysis (AEDA), we measured flavor dilution (FD) factors in SE-SAFE isolates, ranging from 1 to 4096, and in SPME isolates, ranging from 1 to 800. Twenty-eight odorants with higher FD factors and GC-MS responses were quantitated using the internal standard curve method. According to their quantitated results and thresholds in water, their odor activity values (OAVs) were calculated. On the basis of the OAV results, 27 odorants with OAVs ≥ 1 were determined as key odorants in six CSSs. These had previously been reported as key odorants in general soy sauce (GSS), so it was concluded that the key odorants in CSS are the same as those in GSS.

scholarly journals LC-MS/MS for Identifying Patients with CYP24A1 Mutations

2016 ◽  
Vol 62 (1) ◽  
pp. 236-242 ◽  
Author(s):  
Hemamalini Ketha ◽  
Rajiv Kumar ◽  
Ravinder J Singh
Keyword(s):  
Genetic Testing ◽  
Solid Phase ◽  
Internal Standard ◽  
Measurement Range ◽  
High Ratio ◽  
Unknown Etiology ◽  
Loss Of Function ◽  
Serum Samples ◽  
Dihydroxyvitamin D ◽  
Cytochrome P450 Family

Abstract BACKGROUND Patients have been described with loss-of-function CYP24A1 (cytochrome P450, family 24, subfamily A, polypeptide 1) mutations that cause a high ratio of 25-hydroxyvitamin D to 24,25-dihydroxyvitamin D [25(OH)D/24,25(OH)2D], increased serum 1,25-dihydroxyvitamin D, and resulting hypercalcemia, hypercalciuria and nephrolithiasis. A 25(OH)D/24,25(OH)2D ratio that can identify patients who are candidates for confirmatory CYP24A1 genetic testing would be valuable. We validated an LC-MS/MS assay for 24,25(OH)2D (D3 and D2) and determined a 25(OH)D/24,25(OH)2D cutoff to identify candidates for confirmatory genetic testing. METHODS After addition of isotope-labeled internal standard, serum samples were extracted by solid-phase extraction, derivatized with 4-phenyl-1,2,4,-triazoline-3,5-dione, and quantified by LC-MS/MS. We measured 25(OH)D/24,25(OH)2D in 91 healthy patients and 34 patients with clinically suspected CYP24A1-mediated hypercalcemia. RESULTS The limits of detection and quantification were 0.03 (0.2) and 0.1 (0.24) nmol/L, respectively, for 24,25(OH)2D3, and 0.1 (0.23) and 0.5 (1.16) nmol/L for 24,25(OH)2D2. Intra- and interassay imprecision was 4%–15% across the analytical measurement range of 0.1–25 ng/mL (0.2–60 nmol/L). No interference was observed with 25(OH)D and 1,25(OH)2D. 25(OH)D/24,25(OH)2D of 7–35 was observed in healthy patients, whereas in 2 patients with CYP24A1 mutations, 25(OH)D/24,25(OH)2D was significantly increased (99–467; P &lt; 0.001). A 25(OH)D/24,25(OH)2D ratio ≥99 identified patients who were candidates for CYP24A1 genetic testing. CONCLUSIONS Increased 25(OH)D/24,25(OH)2D supports the diagnosis of reduced CYP24A1 activity due to mutations in CYP24A1. Measurement of 25(OH)D/24,25(OH)2D should be considered a part of the clinical workup in patients with hypercalcemia of otherwise unknown etiology.

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