四种阴离子的毛细管电泳电导检测(英文)

 采用柠檬酸 柠檬酸钠作为缓冲体系 ,使用负高压 ,对Cl-,NO3 -,HCO3 -和H2 PO4 -等 4种常见阴离子进行了分离检测 ,研究了缓冲剂的种类、浓度、pH值及操作电压对分离的影响。在选定的条件下 ,4种离子的定量线性范围 :Cl-5 0× 10 -5mol/L～ 2 5× 10 -3 mol/L ,NO3 -6 0× 10 -5mol/L～ 2 0× 10 -3 mol/L ,HCO3 -5 0× 10 -6mol/L～ 2 0× 10 -4 mol/L ,H2 PO4 -6 0× 10 -5mol/L～ 1 0× 10 -3 mol/L ;检出限 :Cl-1 5× 10 -5mol/L ,NO3 -3 0×10 -5mol/L ,HCO3 -1 0× 10 -6mol/L ,H2 PO4 -2 0× 10 -5mol/L ;峰面积的RSD (n =6 ) :Cl-3 1% ,     

胶束电动毛细管色谱分离氨基酸和磷酸化氨基酸

本文报道了胶束电动毛细管色谱分离、汞灯诱导荧光电荷耦合器件检测分析氨基酸和磷酸化氨基酸的 4-氟 - 7-硝基苯 - 2 - 口恶 - 1 ,3-丫唑衍生物。研究表明 ,在 p H9.35的 1 0 mmol/L硼砂和 1 0 mmol/L十二烷基硫酸钠的电泳缓冲介质中 ,5种氨基酸和 3种磷酸化氨基酸在 1 0 min内完全分离 ,检测灵敏度为 1 .2 1× 1 0 - 8～ 5 .2 1×1 0 - 8mol/L ,分离效率达 7.3× 1 0 5～ 3.0× 1 0 5/m理论塔板数 ,结果令人满意     

锌电解液中痕量铜、镉、镍和钴的快速同时测定

研究了丁二酮肟 氨 氯化铵 柠檬酸钠 明胶 抗坏血酸体系中Cu(Ⅱ )、Cd(Ⅱ )、Ni(Ⅱ )和Co(Ⅱ )的络合物吸附波 ,建立了同时、快速测定锌电解溶液中这些痕量元素的新方法。Cu(Ⅱ )、Cd(Ⅱ )、Ni(Ⅱ )和Co(Ⅱ )分别在 - 0 44V、- 0 76V、- 1 0 7V和 - 1 2 4V左右产生灵敏的络合物吸附波。信噪比为 3时 ,其检测限分别为 1 0× 1 0 - 8mol/L、1 3× 1 0 - 8mol/L、2 9× 1 0 - 1 0 mol/L和 3 6×1 0 - 1 1 mol/L。铜、镉、镍和钴的浓度分别为 2 0× 1 0 - 8mol/L～ 2 0× 1 0 - 5 mol/L、3 0× 1 0 - 8mol/L～ 3 0× 1 0 - 5mol/L、5 4× 1 0 - 1 0 mol/L～ 5 4× 1 0 - 7mol/L和 6 8× 1 0 - 1 1 mol/L～ 6 8× 1 0 - 8mol/L时 ,与相应峰电流之间有良好的线性关系。方法已用于锌电解液中铜、镉、镍和钴的快速同时测定 ,相对标准偏差分别小于或等于 4 7%、5 1 %、4 9%和 5 3 %。     

微渗析活体取样与液相色谱安培检测法联用测定鼠脑中黄嘌呤和次黄嘌呤

采用微渗析活体取样技术和高效液相色谱安培检测法 ,测定了鼠脑纹状体中的黄嘌呤和次黄嘌呤。安培检测以玻碳电极为工作电极 ,检测电位为 0 .9V。在 5 .0× 1 0 - 7～ 1 .0× 1 0 - 4 mol/L浓度范围内 ,黄嘌呤和次黄嘌呤的浓度分别与峰电流呈良好的线性关系 ,检出限分别为 8 0× 1 0 - 8mol/L和 3 0× 1 0 - 7mol/L。该方法为生命科学的研究提供了一种新的分析手段     

以酸性铬蓝K作为氢供体的酶催化光度法测定过氧化氢

研究了以酸性铬蓝 K作为氢供体底物的过氧化氢酶 -过氧化氢催化反应体系 ,拟定了测定痕量过氧化氢的新的酶催化光度法。测得该体系的最大反应速率 Vmax值为 6.2 5× 1 0 -3 mol· L-1·S-1,米氏常数 Km值为 2 .78× 1 0 -5mol/L。测定过氧化氢的线性范围为 0 .0 3～ 0 .6mg/L。检出限为 4.6× 1 0 -4 mol/L。方法可应用于雨水中过氧化氢的测定     

镧-滂胺天蓝光度法测定人血清及尿样中的几种抗生素

在pH 2 .8～ 6 .5的条件下 ,镧 和 6 ,6′ (2 ,2′ -二甲氧基 4 ,4′ -亚联苯基双偶氮 )二 (5 羟基 4 氨基 1 ,3 萘二磺酸钠 ) (滂胺开蒸 ,PSB)与硫酸新霉素 (NEO)、硫酸庆大霉素 (GEN)、硫酸卡那霉素 (KANA)反应生成具有明显显色峰和褪色峰的三元蓝色离子缔合物。其最大显色波长位于 6 88nm ,线性范围从 0～ 1 2 .0mg/L至 0～ 1 4 .0mg/L ,摩尔吸收光系数 (ε)在 3.0 8× 1 0 4～ 4 .6 4× 1 0 4L·mol-1 ·cm-1 之间 ;最大褪色波长在6 1 8～ 6 2 4nm之间 ,线性范围从 0～ 1 2 .0mg/L至 0～ 1 5 .0mg/L ,摩尔吸光系数 (ε)在 4 .4 3× 1 0 4～ 1 .1 3× 1 0 5L·mol-1 ·cm-1 之间。探讨了适宜的反应条件、主要分析化学性质及三元缔合物的络合比。该法用于人血清及尿样中新霉素、卡那霉素及庆大霉素含量的测定 ,结果满意     

利用粉末微电极检测谷胱甘肽及L-半胱氨酸

本文研究了谷胱甘肽 ( GSH)和 L-半胱氨酸 ( L- cys)在碳粉末微电极上的电化学行为 ,并分别用乙炔黑粉末和 Ketjenblack粉末填充的微电极检测了溶液中GSH和 L- cys的浓度。 GSH和 L- cys在粉末微电极上的检出限分别为 3.4× 1 0 - 6mol/ L和 2 .5× 1 0 - 6 mol/ L,线性范围分别为 3.6× 1 0 - 5～ 4.5× 1 0 - 3mol/ L和 1 .5×1 0 - 5～ 5 .0× 1 0 - 3mol/ L。采用粉末微电极技术完全避免了尿酸和对 -乙酰氨基苯酚对测量谷胱甘肽的干扰 ;0 .0 6mmol/ L的抗坏血酸引起的干扰约为 8%。     

一种二氮氧化喹恶啉化合物的分光光度法测定

用两种方法对 N,N′-二氧 -2 -甲基喹恶啉进行显色 :( 1 )在氢氧化钠介质中 ,在 70～ 80℃ ,N,N′-二氧 -2 -甲基喹恶啉水溶液产生异构化反应生成蓝色化合物 ,其浓度在 4.0～ 2 0 0× 1 0 - 3 mg/ m L范围符合比耳定律 ;( 2 )在亚硫酸氢钠 /浓硫酸介质中 ,在室温条件下 ,2 0～ 3 0 min后还原成淡黄绿到绿色化合物 ,在 1 0 .0～ 70 0× 1 0 - 3mg/ m L浓度范围符合比耳定律。此项研究为这类抗菌药物中间体提供了一种定量分析方法     

柱前荧光衍生-高效液相色谱法测定尿中雌二醇

建立了对硝基苯甲酰氯柱前荧光衍生 高效液相色谱法测定尿中 1 7α 和 1 7β 雌二醇的方法。尿样经盐酸水解、固相萃取柱浓缩、净化分离后 ,在无水条件下与对硝基苯甲酰氯反应生成荧光产物 ,再用高效液相色谱 荧光检测器测定。流动相为乙腈 水 (5 5∶45 )。线性范围为 7.0× 1 0 - 3～ 1 0mg L ,检出限均为 7.0× 1 0 - 3mg L,相对标准差分别为 0 .93 %～ 1 .5 %和 0 .88%～ 1 .3 %。平均回收率分别为 83 .5 %和 88.2 %。     

Ru(bipy)_3~(2+)-CO_3~(2-)-SO_3~(2-)-KClO_3体系化学发光法测定空气中的二氧化硫

提出了 Ru(bipy) 2 +3 - CO2 -3 - SO2 -3 - KCl O3 体系化学发光法测定溶液中亚硫酸盐的方法。SO2 -3 浓度与化学发光强度在 1 .0× 1 0 - 7～ 1 .0× 1 0 - 4mol/L 范围内成正比 ,检出限为 8.76× 1 0 - 8mol/L,对 1 .0× 1 0 - 4mol/L SO2 - 3 溶液 6次测定的相对标准偏差为 2 .9%。该法用三乙醇胺作为吸收液 ,成功地用于测定空气中二氧化硫的含量 ,结果满意。     

A simple and sensitive assay for the quantitative analysis of paclitaxel in human and mouse plasma and brain tumor tissue using coupled liquid chromatography and tandem mass spectrometry

The development and validation of an assay for the determination of paclitaxel in human plasma, human brain tumor tissue, mouse plasma and mouse brain tumor tissue is described. Paclitaxel was extracted from the matrices using liquid-liquid extraction with tert-butyl methyl ether, followed by chromatographic analysis using an alkaline eluent. Positive ionization electrospray tandem mass spectrometry was performed for selective and sensitive detection. The method was validated according to the FDA guidelines on bioanalytical method validation. Validation results indicate that calibration standards in human plasma can be used to quantify paclitaxel in all tested matrices. In human samples, the validated range for paclitaxel was from 0.25-1000 ng ml(-1) using 200 microl plasma aliquots and from 5 to 5000 ng g(-1) using 50 microl tumor homogenate aliquots (0.2 g tissue ml(-1) control human plasma). In mice, the ranges were 1-1000 ng ml(-1) and 5-5000 ng g(-1) using 50 microl of mouse plasma and 50 microl of tumor homogenate aliquots (0.2 g tissue ml(-1) control human plasma), respectively. The method can be applied to studies generating only small sample volumes (e.g. mouse plasma and tumor tissue), but also to studies in human plasma requiring a lower limit of quantitation. The assay was applied successfully to several studies with both human and mouse samples.     

Evaluation of matrix effects in analysis of estrogen using liquid chromatography–tandem mass spectrometry

Matrix effects of different biological samples, including phosphate‐buffered saline–bovine serum albumin (PBS‐BSA), gelded horse serum, mouse serum, and mouse brain, were investigated for the determination of 17α‐ and β‐estradiol using derivatization with dansyl chloride prior to LC‐MS/MS. Matrix effects were evaluated based on the slopes of regression lines plotted from results obtained in biological matrices versus pure standard solutions. Such plots indicate the enhancement or suppression of signal based on the presence of a particular biological fluid for a particular method. The matrix effects from PBS‐BSA were similar to those of mouse serum. In contrast, analyses performed from horse serum and mouse brain yielded significant ion suppression, especially for 17β‐estradiol. Precipitation during derivatization was observed when pre‐concentrated samples were processed with ethyl acetate as an extraction solvent. This was overcome with the use of methyl tert‐butyl ether; however, matrix effects from this preparation were still present, evidenced by signal suppression and poor linearity in the standard curve. This work affirms that caution should be taken in the transfer of methods for use with different biological matrices, especially in the case where surrogate matrices are necessary for calibration purposes.     

Efficient determination of purine metabolites in brain tissue and serum by high‐performance liquid chromatography with electrochemical and UV detection

The purine metabolic pathway has been implicated in neurodegeneration and neuroprotection. High‐performance liquid chromatography (HPLC) is widely used to determine purines and metabolites. However, methods for analysis of multiple purines in a single analysis have not been standardized, especially in brain tissue. We report the development and validation of a reversed‐phase HPLC method combining electrochemical and UV detection after a short gradient run to measure seven purine metabolites (adenosine, guanosine, inosine, guanine, hypoxanthine, xanthine and urate) from the entire purine metabolic pathway. The limit of detection (LoD) for each analyte was determined. The LoD using UV absorption was 0.001 mg/dL for hypoxanthine (Hyp), inosine (Ino), guanosine (Guo) and adenosine (Ado), and those using coulometric electrodes were 0.001 mg/dL for guanine (Gua), 0.0001 mg/dL for urate (UA) and 0.0005 mg/dL for xanthine (Xan). The intra‐ and inter‐day coefficient of variance was generally <8%. Using this method, we determined basal levels of these metabolites in mouse brain and serum, as well as in post‐mortem human brain. Peak identities were confirmed by enzyme degradation. Spike recovery was performed to assess accuracy. All recoveries fell within 80–120%. Our HPLC method provides a sensitive, rapid, reproducible and low‐cost method for determining multiple purine metabolites in a single analysis in serum and brain specimens. Copyright © 2012 John Wiley & Sons, Ltd.     

Analysis of dansyl derivatives of di- and polyamines in mouse brain, human serum and duodenal biopsy specimens by high-performance liquid chromatography on a standard reversed-phase column

The concentrations of putrescine, spermine and spermidine were measured in human serum, children's duodenal biopsy specimens and mouse brain homogenates by high-performance liquid chromatography. The chromatographic analysis was performed on dansyl derivatives of the polyamines using a reverse-phase system with an ion-pairing retention mechanism (heptane sulphonate). Capacity factors were determined at different concentrations of acetonitrile. Simple linear gradients were set up for fast (15 min) or routine (25 min) analysis. Three fluorescence detectors were compared for these determinations and their detection limits determined. The minimum detectable amount of polyamines was 25 fmol compared to 500 fmol with standard detectors. While samples prepared from tissues did not require a high sensitivity, a detector of better performance was needed to assay the polyamines in human serum.     

Determination of Anagliptin in Serum by Mixed-Hemimicelle Magnetic Solid-Phase Extraction with Surfactant-Coated Iron(II,III) Nanocomposites and High-Performance Liquid Chromatography

Magnetic solid-phase extraction based on the adsorption of sodium dodecyl sulfate on the surface of Fe₃O₄ nanoparticles was used to isolate the new hypoglycemic drug anagliptin in human and mouse serum before determination by high-performance liquid chromatography. The magnetic adsorbent was characterized by transmission electron microscopy, Fourier transform infrared spectroscopy, and the zeta potential. The factors affecting the extraction performance such as the type of surfactant, the amount of adsorbent and sodium dodecyl sulfate, pH of solution, time and temperature of adsorption and elution, and eluent type were examined. Under the optimized conditions, the adsorbent could be reused for six times and the efficiency of extraction or elution was over 95.0%. The calibration curve was linear in the range of 0.050–4.00?µg?mL^?1, with detection limits of 0.021 and 0.023?µg?mL^?1 for human and mouse serum, respectively. The recovery values of 92.0–99.1% (human serum) or 94.8–105.7% (mouse serum) illustrated the accuracy of the proposed method. Moreover, it may be the first time that this extraction method has been used to determine anagliptin in biological liquids.     

Pharmacokinetic application of a bio‐analytical LC‐MS method developed for 5‐fluorouracil and methotrexate in mouse plasma,brain and urine

In the past we have reported significant cognitive deficits in mice receiving 5‐fluorouracil in combination with low‐dose methotrexate. To explain such interactions, a pharmacokinetic study was designed. A sensitive bio‐analytical method was therefore developed and validated for 5‐fluorouracil and methotrexate in mouse plasma, brain and urine with liquid chromatography coupled to a single quadrupole mass spectrometer. Chromatographic separation was accomplished by Agilent® Zorbax® SB‐C₁₈ column, with isocratic elution (5 mM ammonium acetate and methanol, 70:30, %v/v) at a flow rate of 300 μL/min. The limit of quantitation for both drugs was 15.6 ng/mL (plasma and brain) and 78.1 ng/mL (urine), with interday and intraday precision and accuracy ≤15% and a total run time of 6 min. This bio‐analytical method was used for the pharmacokinetic characterization of 5‐fluorouracil and methotrexate in mouse plasma, brain and urine over a period of 24 h. This method allowed characterization of the brain concentrations of 5‐fluorouracil over a period of 24 h. Copyright © 2013 John Wiley & Sons, Ltd.     

Determination of idebenone in rat serum and brain by high-performance liquid chromatography using platinum catalyst reduction and electrochemical detection.

A high-performance liquid chromatographic determination of idebenone, a new cerebral metabolism-improving agent, in rat serum and brain has been developed. After separation of idebenone on a reversed-phase column, idebenone was reduced once in a platinum catalyst reduction column connected on-line, then monitored quantitatively by electrochemical detection. A linear relationship between the peak-height ratio of idebenone to the internal standard and idebenone concentration was observed in the range 0.015-50 ng with a detection limit of 5 pg (signal-to-noise ratio = 5). This method was satisfactorily rapid and sensitive, and was successfully applied to the determination of idebenone in rat serum and brain tissues.     

Brain tumor diagnostic model and dietary effect based on extracellular vesicle microbiome data in serum

The human microbiome has been recently associated with human health and disease. Brain tumors (BTs) are a particularly difficult condition to directly link to the microbiome, as microorganisms cannot generally cross the blood–brain barrier (BBB). However, some nanosized extracellular vesicles (EVs) released from microorganisms can cross the BBB and enter the brain. Therefore, we conducted metagenomic analysis of microbial EVs in both serum (152 BT patients and 198 healthy controls (HC)) and brain tissue (5 BT patients and 5 HC) samples based on the V3–V4 regions of 16S rDNA. We then developed diagnostic models through logistic regression and machine learning algorithms using serum EV metagenomic data to assess the ability of various dietary supplements to reduce BT risk in vivo. Models incorporating the stepwise method and the linear discriminant analysis effect size (LEfSe) method yielded 12 and 29 significant genera as potential biomarkers, respectively. Models using the selected biomarkers yielded areas under the curves (AUCs) >0.93, and the model using machine learning resulted in an AUC of 0.99. In addition, Dialister and [Eubacterium] rectale were significantly lower in both blood and tissue samples of BT patients than in those of HCs. In vivo tests showed that BT risk was decreased through the addition of sorghum, brown rice oil, and garlic but conversely increased by the addition of bellflower and pear. In conclusion, serum EV metagenomics shows promise as a rich data source for highly accurate detection of BT risk, and several foods have potential for mitigating BT risk.Subject terms: Diagnostic markers, Machine learning     

Determination of Pharmacokinetics of Tanshinone II A in Mouse Plasma and Brain by High Performance Liquid Chromatography

High performance liquid chromatography (HPLC) method was developed to measure the concentration of tanshinone IIA (Ts IIA) in mouse plasma and brain. The method was applied to preliminary study on pharmacokinetics of Ts IIA in mouse plasma and brain. After an administration of 8.0 mg kg⁻¹ of Ts IIA by an intravenous injection, plasma and brain samples were collected and extracted by liquid-liquid extraction with ethyl acetate and determined by HPLC. This method has a linear range from 0.05 to 7.12 mg l⁻¹ with correlation coefficients of 0.9984 in plasma and a linear range from 0.022 to 2.37 mg l⁻¹ with correlation coefficients of 0.9988 in brain. The limits of quantitation in plasma and brain were 0.050 and 0.022 mg l⁻¹, respectively, and the limits of detection were 0.026 and 0.017 mg l⁻¹, respectively. The intra-day and inter-day precisions were less than 10.3%. The developed method was selective, accurate, and sensitive and can be applied to determine the concentration of Ts IIA in mouse plasma and brain quantitatively after intravenous administration of Ts IIA. It was suitable for the pharmacokinetic study of Ts IIA. The plasma concentration-time curve was fitted as three-compartment model. The peak concentration of Ts IIA in mouse plasma was 1.58 mg l⁻¹, and the value of the areas under the plasma concentration-time curve (AUC 0-t) was 68.18 mg l⁻¹ min⁻¹. The concentration of Ts IIA in mouse brain achieved the peak value of 0.17 mg l⁻¹ 5 min after mainlined, and Ts IIA could be still detected in brain 480 min after mainlined. The results indicated that Ts IIA readily penetrated the blood-brain barrier and could stay in the brain for a long time.     

Bisphosphonate derivatives of nucleoside antimetabolites: hydrolytic stability and hydroxyapatite adsorption of 5'-beta,gamma-methylene and 5'-beta,gamma-(1-hydroxyethylidene) triphosphates of 5-fluorouridine and ara-cytidine

Kinetics of the hydrolytic reactions of four bisphosphonate derivatives of nucleoside antimetabolites, viz., 5-fluorouridine 5'-beta,gamma-(1-hydroxyethylidene) triphosphate ( 4), 5-fluorouridine 5'-beta,gamma-methylene triphosphate ( 5), ara-cytidine 5'-beta,gamma-(1-hydroxyethylidene) triphosphate ( 6), and ara-cytidine 5'-beta,gamma-methylene triphosphate ( 7), have been studied over a wide pH range (pH 1.0-8.5) at 90 degrees C. With each compound, the disappearance of the starting material was accompanied by formation of the corresponding nucleoside 5'-monophosphate, the reaction being up to 2 orders of magnitude faster with the beta,gamma-(1-hydroxyethylidene) derivatives ( 4, 6) than with their beta,gamma-methylene counterparts ( 5, 7). With compound 7, deamination of the cytosine base competed with the phosphate hydrolysis at pH 3-6. The measurements at 37 degrees C (pH 7.4) in the absence and presence of divalent alkaline earth metal ions (Mg (2+) and Ca (2+)) showed no sign of metal ion catalysis. Under these conditions, the initial product, nucleoside 5'-monophosphate, underwent rapid dephosphorylation to the corresponding nucleoside. Hydrolysis of the beta,gamma-methylene derivatives ( 5, 7) to the corresponding nucleoside 5'-monophosphates was markedly faster in mouse serum than in aqueous buffer (pH 7.4), the rate-acceleration being 5600- and 3150-fold with 5 and 7, respectively. In human serum, the accelerations were 800- and 450-fold compared to buffer. In striking contrast, the beta,gamma-(1-hydroxyethylidene) derivatives did not experience a similar decrease in hydrolytic stability. The stability in human serum was comparable to that in aqueous buffer (tau 1/2 = 17 and 33 h with 4 and 6, respectively), and on going to mouse serum, a 2- to 4-fold acceleration was observed. To elucidate the mineral-binding properties of 4- 7, their retention on a hydroxyapatite column was studied and compared to that of zoledronate ( 1a) and nucleoside mono-, di-, and triphosphates.