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<br>Display Omitted<br>• 4′-Carbonyl chloride rosamine was synthesized and used for NTs by UHPLC-MS/MS. • <b>In situ</b> UA-DDLLME was reported for the simultaneous determination of AANTs and MANTs. • The method was sensitive, selective, low matrix effect, speedy and eco-friendly. • A new analytical tool in diagnosis of AD-related disease.<br>Neurotransmitters (NTs) may play an important role in neurodegenerative disorders such as Alzheimer’s disease (AD). In order to investigate the potential links, a new simple, fast, accurate and sensitive analytical method, based on <b>in situ</b> ultrasound-assisted derivatization dispersive liquid-liquid microextraction (<b>in situ</b> UA-DDLLME) coupled with ultra high-performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS), has been developed and validated. The quantitation of amino acid neurotransmitters (AANTs) and monoamine neurotransmitters (MANTs) in urine of AD rats were performed in this work. The <b>in situ</b> UA-DDLLME procedure involved the rapid injection of the mixture of low toxic 4-bromoanisole (extractant) and acetonitrile (dispersant), which containing the new designed and synthesized 4′-carbonyl chloride rosamine (CCR) as derivatization reagent, into the aqueous phase of real sample and buffer. Under the selected conditions, the derivatization and microextraction of analytes were simultaneously completed within 1 min. Good linearity for each analyte (R > 0.992) was observed with low limit of detections (LODs, S/N > 3). Moreover, the proposed method was compared with direct detection or other reported methods, and the results showed that low matrix effects and good recoveries results were obtained in this work. Taken together, <b>in situ</b> UA-DDLLME coupled with UHPLC-MS/MS analysis was demonstrated to be a good method for sensitive, accurate and simultaneous monitoring of AANTs and MANTs. This method would be expected to be highly useful in AD diseases’ clinical diagnostics and may have potential value in monitoring the efficacy of treatment.
A novel hyphenated method based on ultrasound-assisted dispersive liquid-liquid microextraction coupled to precolumn derivatization has been established for the simultaneous determination of bisphenol A, 4-octylphenol, and 4-nonylphenol by high-performance liquid chromatography with fluorescence detection. Different parameters that influence microextraction and derivatization have been optimized. The quantitative linear range of analytes is 5.0-400.0 ng/L, and the correlation coefficients are more than 0.9998. Limits of detection for soft drinks and dairy products have been obtained in the range of 0.5-1.2 ng/kg and 0.01-0.04 μg/kg, respectively. Relative standard deviations of intra- and inter-day precision for retention time and peak area are in the range of 0.47-2.31 and 2.76-8.79%, respectively. Accuracy is satisfactory in the range of 81.5-118.7%. Relative standard deviations of repeatability are in the range of 0.35-1.43 and 2.36-4.75% for retention time and peak area, respectively. Enrichment factors for bisphenol A, 4-octylphenol, and 4-nonylphenol are 170.5, 240.3, and 283.2, respectively. The results of recovery and matrix effect are in the range of 82.7-114.9 and 92.0-109.0%, respectively. The proposed method has been applied to the determination of bisphenol A, 4-octylphenol, and 4-nonylphenol in soft drinks and dairy products with much higher sensitivity than many other methods.
A novel hyphenated technique based on ultrasonic-assisted dispersive liquid-liquid microextraction (UA-DLLME) coupled with derivatization has been established for the determination of brassinolide (BL, a representative of brassinosteroids) by HPLC fluorescence detection. 9-Phenanthreneboronic acid is used as labeling reagent of BL. UA-DLLME parameters containing type and volume of extraction and disperser solvent, pH and ultrasonication time are optimized. Derivatization parameters are optimized included amount of 9-phenanthreneboronic acid, volume ratio of pyridine, derivatization time and temperature. Under optimal conditions, quantitative linear range of BL is 50-1,000 ng L<sup>−1</sup> and excellent linear response is observed with correlation coefficient of 0.9996. Limit of detection and limit of quantification are calculated as 8.0 and 25.0 ng L<sup>−1</sup>, respectively. RSDs of retention time and peak area are in the range of 0.68-0.97 % and 4.61-6.54 % for intra-day precision, 1.32-1.94 % and 7.28-9.75 % for inter-day precision, respectively. Accuracy is satisfactory in the range of 82.3-125.1 %. RSDs’ values of repeatability are in the range of 0.82-1.79 and 3.95-8.53 % for retention time and peak area, respectively. Enrichment factor for BL is 189. The results of recovery and matrix effect are in the range of 82.0-108.6 and 90.0-115.3 %, respectively. The proposed method has been applied for the determination of BL in <i>Arabidopsis thaliana</i>, <i>Daucus carota</i> and <i>Brassica campestris</i> L. leaves with much higher sensitivity than many other methods.
• A new low toxic dual-UADLLME coupled with microwave-assisted derivatization was proposed. • 4′-Carboxy-substituted rosamine was firstly used as derivatization reagent. • Simultaneous determination of PPD and PPT in rat plasma was achieved by UHPLC-MS/MS. • This method was successfully applied to pharmacokinetics study.<br>This paper, for the first time, reported a speedy hyphenated technique of low toxic dual ultrasonic-assisted dispersive liquid-liquid microextraction (dual-UADLLME) coupled with microwave-assisted derivatization (MAD) for the simultaneous determination of 20(<b>S</b>)-protopanaxadiol (PPD) and 20(<b>S</b>)-protopanaxatriol (PPT). The developed method was based on ultra high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) detection using multiple-reaction monitoring (MRM) mode. A mass spectrometry sensitizing reagent, 4′-carboxy-substituted rosamine (CSR) with high reaction activity and ionization efficiency was synthesized and firstly used as derivatization reagent. Parameters of dual-UADLLME, MAD and UHPLC-MS/MS conditions were all optimized in detail. Low toxic brominated solvents were used as extractant instead of traditional chlorinated solvents. Satisfactory linearity, recovery, repeatability, accuracy and precision, absence of matrix effect and extremely low limits of detection (LODs, 0.010 and 0.015 ng/mL for PPD and PPT, respectively) were achieved. The main advantages were rapid, sensitive and environmentally friendly, and exhibited high selectivity, accuracy and good matrix effect results. The proposed method was successfully applied to pharmacokinetics of PPD and PPT in rat plasma.
Fatty acids in Herpetospermum seed oil from supercritical CO2 extraction were analyzed by HPLC fluorescence detection (HPLC-FLD) with pre-column derivatization and GC-MS. After derivatizing 39 kinds of saturated and unsaturated fatty acids used 1-[ 2- ( p-toluenesulfonate ) ethyl]-2-phenylimidazole [ 4,5-f] 9,10-phenanthrene ( TSPP ) as pre-column derivatization reagent. All the fatty acid derivatives were separated with a good baseline resolution in conjunction with a gradient elution. The external standard method for the simultaneous quantitative determination of 39 fatty acids was developed and applied for the determination of the free fatty acid contents in Herpetospermum seed oil samples obtained from supercritical CO2 extraction coupled with orthogonal tests, ultrasound-assisted extraction and microwave-assisted reflux extraction. The mass percent of oleic acid, linoleic acid and linolenic acid and the ratio of unsaturated fatty acids and all fatty acids in 9 orthogonal test samples were contrasted. The results indicated that the mass percent of oleic acid, linoleic acid and linolenic acid in Herpetospermum seed oil are up to 34.65% ( 147. 14 mg/g), 22.85% (97.03 mg/g), 20. 86% ( 88. 56 rag/g), respectively, and ratio of unsaturated fatty acids and all fatty acids is 79%. Furthermore, by GC-MS method, the acid catalysis and alkaline catalysis of the methyl esterifying reaction were discussed for the analysis fatty acids in Herpetospermum seed oil, and the optimum GC-MS conditions were obtained. Simultaneously, the characteristics of HPLC and GC-MS methods were discussed about analyzing fatty acids.
<p>A simple and sensitive method for the determination of free fatty acids (FFAs) using acridoné9́ethyĺṕtoluenesulfonate (AETS) as a fluorescence derivatization reagent by high performance liquid chromatography (HPLC) has been developed. Free fatty acid derivatives were separated on an Eclipse XDB́C<sub>8</sub> column with a good baseline resolution and detected with the fluorescence of which excitation and emission wavelengths of derivatives were set at <sub>ex</sub>=404 and <sub>em</sub>=440 nm, respectively. Identification of 19 fatty acid derivatives was carried out by online post́column mass spectrometry with an atmospheric pressure chemical ionization (APCI) source under positivéion detection mode. Nineteen FFAs from the extract of <i>Lomatogonium rotatum</i> are sensitively determined. The results indicate that the plant <i>Lomatogonium rotatum</i> is enriched with an abundance of FFAs and FFAs of higher contents, which mainly focus on even carbon atoms, C<sub>14</sub>, C<sub>16</sub>, and C<sub>18</sub>. The validation of the method including linearity, repeatability, and detection limits was examined. Most linear correlation coefficients for fatty acid derivatives are >0.9989, and detection limits (at signaĺtónoise of 3:1) are 12.3-43.7 fmol. The relative standard deviations (RSDs) of the peak areas and retention times for 19 FFAs standards are <2.24% and 0.45%, respectively. The established method is rapid and reproducible for the separation determination of FFAs from the extract of <i>Lomatogonium rotatum</i> with satisfactory results.</p>
<br>Display Omitted<br>• A new coupled method of stable isotope-labeling derivatization with UA-DLLME was reported. • Simultaneous determination of multiple neurotransmitters with UHPLC-MS/MS. • Heavy labeled d3-MASC standards were used as the internal standards for quantification. • The method was sensitive, accurate and low matrix effect. • Application for neurotransmitters dynamic changes in rats brain microdialysates.<br>In this work, for the first time, a new hyphenated technique of stable isotope-labeling derivatization-ultrasound-assisted dispersive liquid-liquid microextraction has been developed for the simultaneous determination of monoamine neurotransmitters (MANTs) and their biosynthesis precursors and metabolites. The developed method was based on ultra high performance liquid chromatography tandem mass spectrometry detection using multiple-reaction monitoring mode. A pair of mass spectrometry sensitizing reagents, d0-10-methyl-acridone-2-sulfonyl chloride and d3-10-methyl-acridone-2-sulfonyl chloride, as stable isotope probes was utilized to facilely label neurotransmitters, respectively. The heavy labeled MANTs standards were prepared and used as internal standards for quantification to minimize the matrix effects in mass spectrometry analysis. Low toxic bromobenzene (extractant) and acetonitrile (dispersant) were utilized in microextraction procedure. Under the optimized conditions, good linearity was observed with the limits of detection (S/N > 3) and limits of quantification (S/N > 10) in the range of 0.002-0.010 and 0.015-0.040 nmol/L, respectively. Meanwhile, it also brought acceptable precision (4.2-8.8%, peak area RSDs %) and accuracy (recovery, 96.9-104.1%) results. This method was successfully applied to the simultaneous determination of monoamine neurotransmitters and their biosynthesis precursors and metabolites in rat brain microdialysates of Parkinson's disease and normal rats. This provided a new method for the neurotransmitters related studies in the future.
In this work, a hyphenated technique of dual ultrasound-assisted dispersive liquid-liquid microextraction combined with microwave-assisted derivatization followed by ultra high performance liquid chromatography tandem mass spectrometry has been developed for the determination of phytosterols in functional foods and medicinal herbs. Multiple reaction monitoring mode was used for the tandem mass spectrometry detection. A mass spectrometry sensitive reagent, 4'-carboxy-substituted rosamine, has been used as the derivatization reagent for five phytosterols, and internal standard diosgenin was used for the first time. Parameters for the dual microextraction, microwave-assisted derivatization, and ultra high performance liquid chromatography tandem mass spectrometry were all optimized in detail. Satisfactory linearity, recovery, repeatability, accuracy and precision, absence of matrix effect, extremely low limits of detection (0.005-0.015 ng/mL) and limits of quantification (0.030-0.10 ng/mL) were achieved. The proposed method was compared with previously reported methods. It showed better sensitivity, selectivity, and accuracy. The matrix effect was also significantly reduced. The proposed method was successfully applied to the determination of five phytosterols in vegetable oil (sunflower oil, olive oil, corn oil, peanut oil), milk and orange juice (soymilk, peanut milk, orange juice), and medicinal herbs (Ginseng, Ganoderma lucidum, Cordyceps, Polygonum multiflorum) for the quality control of functional foods and medicinal herbs.
• In situ derivatization-UADLLME was firstly reported for NTs in rat brain microdialysates. • Lissamine rhodamine B sulfonyl chloride was firstly used as derivatization reagent. • The method was simple, rapid, green, efficient, sensitive and low matrix effect. • This method was successfully applied for Parkinson’s rat brain microdialysates.<br>Simultaneous monitoring of several neurotransmitters (NTs) linked to Parkinson’s disease (PD) has important scientific significance for PD related pathology, pharmacology and drug screening. A new simple, fast and sensitive analytical method, based on in situ derivatization-ultrasound-assisted dispersive liquid-liquid microextraction (in situ DUADLLME) in a single step, has been proposed for the quantitative determination of catecholamines and their biosynthesis precursors and metabolites in rat brain microdialysates. The method involved the rapid injection of the mixture of low toxic bromobenzene (extractant) and acetonitrile (dispersant), which containing commercial Lissamine rhodamine B sulfonyl chloride (LRSC) as derivatization reagent, into the aqueous phase of sample and buffer, and the following in situ DUADLLME procedure. After centrifugation, 50 μL of the sedimented phase (bromobenzene) was directly injected for ultra high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) detection in multiple reaction monitoring (MRM) mode. This interesting combination brought the advantages of speediness, simpleness, low matrix effects and high sensitivity in an effective way. Parameters of in situ DUADLLME and UHPLC-MS/MS conditions were all optimized in detail. The optimum conditions of in situ DUADLLME were found to be 30 μL of microdialysates, 150 μL of acetonitrile containing LRSC, 50 μL of bromobenzene and 800 μL of NaHCO3-Na2CO3 buffer (pH 10.5) for 3.0 min at 37 °C. Under the optimized conditions, good linearity was observed with LODs (S/N > 3) and LOQs (S/N > 10) of LRSC derivatized-NTs in the range of 0.002-0.004 and 0.007-0.015 nmol/L, respectively. It also brought good precision (3.2-12.8%, peak area CVs%), accuracy (94.2-108.6%), recovery (94.5-105.5%) and stability (3.8-8.1%, peak area CVs%) results. Moreover, LRSC derivatization significantly improved chromatographic resolution and MS detection sensitivity of NTs when compared with the reported studies through the introduction of a permanent charged moiety from LRSC into NTs. Taken together, this in situ DUADLLME method was successfully applied for the simultaneous determination of six NTs in biological samples.