Fast Determination of Fumonisin B1 and B2 in Corn Using a Modified QuEChERS Method and LC–MS–MS

A fast analytical method for the simultaneous determination of fumonisin B₁ (FB₁) and fumonisin B₂ (FB₂) in corn using a novel QuEChERS method and LC–MS–MS was developed and validated. Samples were extracted with methanol–water (3:1 v/v) by means of ultrasonic extraction. The extract was purified with a novel modified QuEChERS method. Firstly, FB₁ and FB₂ in the extract were retained with primary secondary amine (PSA). Then, FB₁ and FB₂ were released from PSA with 1.0 % formic acid in methanol. The final eluate was diluted with water, and analyzed by LC–MS–MS on a Waters Acquity BEH C₁₈ column with 0.1 % formic acid in water/methanol as mobile phase with gradient elution. Mean recoveries of 83.5–102.4 % with CVs of 3.6–10.5 % were obtained at fortification levels of 2, 50 and 1,000 μg kg⁻¹. The limit of quantification was 2.0 μg kg⁻¹.

     

高效薄层色谱法测定黄曲霉毒素B1、B2、G1、G2

1引言本文建立了以多功能净化拄（MFC）净化,结合高效薄层色谱法测定食品中黄曲霉毒素B1、B2、G1、G2的方法,与经典薄层色谱法相比,样品前处理过程简单快速,且净化效果良好;改变了传统的双向展开方式,以单相展开即可达到分离检测的目的,大大提高了检测速度和效率。本方法用于花生样品的检测,取得良好的效果。2实验部分2．1试剂与仪器水为重蒸去离子水;甲醇,乙腈,苯均为分析纯;黄曲霉毒素标准储备液：黄曲霉毒素（美国SIGMA公司,纯度≥99％）B1＋B2＋G1＋G2各1．0mg/L,溶于苯＋乙腈（98＋2,V/V）;黄曲霉毒素标准溶液…     

LC–MS and UPLC–Quadrupole Time-of-Flight MS for Identification of Photodegradation Products of Aflatoxin B1

UV irradiation of a solution of aflatoxin B₁ in acetonitrile resulted in three major degradation products which have been identified by LC–MS. Accurate masses and proposed molecular formulas of the degradation products—315.0868 (C₁₇H₁₅O₆), 285.0758 (C₁₆H₁₃O₅), and 275.0553 (C₁₄H₁₁O₆)—were obtained with low mass error and high matching property by ultra-performance liquid chromatography–quadrupole time-of-flight mass spectrometry (UPLC–Q-TOF MS). Structural formulas of the photodegradation products, and the degradation pathways leading to the compounds, are proposed on the basis of the molecular formulas and MS–MS spectra. UPLC–Q-TOF MS has been recognized as a powerful analytical tool for qualitative analysis of trace materials and degradation products.     

固相萃取-高效液相色谱柱后衍生荧光检测花生中黄曲霉毒素B1,B2,G1和G2

测定黄曲霉毒素主要有薄层色谱法、往前衍生液相色谱法和柱后衍生液相色谱法等。样品净化主要有液．液分配、C18键合柱、免疫亲和柱等方法。OASIS^R HLB是Waters公司近几年开发的亲水亲酯固相萃取柱,已用于腐败生物组织中吗啡的检测,它与传统的C18柱相比具有选择范围广、吸附能力强、重现性好、回收率高等特点,但尚未见应用于花生中黄曲霉毒素测定的报道。本文采用OASIS^R HLB固相小柱,建立了以碘作为柱后衍生试剂,反相液相色谱荧光检测花生中黄曲霉毒素B1,B2,G1,G2的分析方法、该法简单,快速,分离能力强,基体干扰少,准确度高。     

Determination of Amphotericin B in Human Cerebrospinal Fluid by LC–MS–MS

A simple, specific and sensitive column liquid chromatography–tandem mass spectrometry method has been developed for the determination of amphotericin B in human cerebrospinal fluid. Samples were prepared by dilution with methanol and quantitated by MS–MS detection in the positive mode. The determination was validated in the concentration range of 0.5–100 ng mL^?1 using 100 μL of human cerebrospinal fluid. The method was successfully used to support routine therapeutic drug monitoring.     

LC–MS–MS Determination of Rotenone, Deguelin, and Rotenolone in Human Serum

For the first time we report a rapid and sensitive LC–MS–MS method for quantification of rotenone, deguelin, and rotenolone in human serum. The analytical procedure involves extraction with ethyl acetate without further clean-up. The active ingredients were separated on a C₈ reversed-phase column by isocratic elution. Eleven simultaneous transitions of precursor ions were monitored. Excellent selectivity and sensitivity enables quantification and identification of low levels of rotenoids (LOD 2 ng mL^?1, LOQ 5 ng mL^?1) in human serum.     

Application of CE–ICP–MS and CE–ESI–MS in metalloproteomics: challenges,developments, and limitations

Application of capillary electrophoresis (CE) as a high-resolution separation technique in metalloproteomics research is critically reviewed. The focus is on the requirements and challenges involved in coupling CE to sensitive element and molecule-specific detection techniques such as inductively coupled plasma mass spectrometry (ICP–MS) or electrospray ionisation mass spectrometry (ESI–MS). The complementary application of both detection techniques to the structural and functional characterisation of metal-binding proteins and their structural metal-binding moieties is emphasised. Beneficial aspects and limitations of mass spectrometry hyphenated to CE are discussed, on the basis of the literature published in this field over the last decade. Recent metalloproteomics applications of CE are reviewed to demonstrate its potential and limitations in modern biochemical speciation analysis and to indicate future directions of this technique.     

Iodination of B12H11OC(O)CH2–3, B12H11OH2–, and B12H11SCN2–

Reactions of iodination of monosubstituted derivatives of B₁₂H₁₁X^2–anion (X = OC(O)CH₃, OH, SCN) were studied. The reactions were shown to proceed smoothly to give B₁₂H₁₀(OC(O)CH₃)I^2–((carboxy)(iodo)[decahydro[I _h1551-²⁰-closo]dodecaborate(2–)] anion), B₁₂H₁₀(OH)I^2–((hydroxo)(iodo)[decahydro[I _h1551-²⁰-closo]dodecaborate(2–)] anion), and B₁₂H₁₀(SCN)I^2–((thiocyanato)(iodo)[decahydro[I _h1551-²⁰-closo]dodecaborate(2–)] anion) in high yields, irrespective of the solvent used (benzene, H₂O–ROH, where R = C₂H₅, CH₂CH₂CH₃).¹     

花生中黄曲霉毒素B1、B2、G1、G2的多功能净化柱-高效薄层色谱分析

建立了一种测定食品中黄曲霉毒素（ ＡＦＴ） Ｂ１ 、Ｂ２ 、Ｇ１ 、Ｇ２ 的多功能净化柱（ ＭＦＣ） 净化, 单相展开的薄层色谱法。 以乙腈－ 水（ 体积比９ ∶１） 提取样品中ＡＦＴ, 经ＭＦＣ 净化浓缩后, 采用ＨＳＧ６０ 薄层板, 以丙酮－ 氯仿（ 体积比９ ∶１） 展开, 薄层扫描仪荧光检测扫描定量。该法用于花生样品的检测,４ 种毒素的分离良好; 线性范围：０ ．０５ ～１ ．０ ｎｇ, 相关系数≥０ ．９９９ １; 检出限均达到０ ．５ ×１０ － ９ ; 相对标准偏差为４ ．６７ ％ ～１０ ．２１ ％ ; 样品加标０．５ ×１０ － ９ ～１０ ×１０ － ９ , 平均回收率为８６ ．５ ％ ～９９ ．０％ 。     

LC–MS–MS determination of ibuprofen, 2-hydroxyibuprofen enantiomers,and carboxyibuprofen stereoisomers for application in biotransformation studies employing endophytic fungi

The purpose of this study was the development and validation of an LC–MS–MS method for simultaneous analysis of ibuprofen (IBP), 2-hydroxyibuprofen (2-OH-IBP) enantiomers, and carboxyibuprofen (COOH-IBP) stereoisomers in fungi culture medium, to investigate the ability of some endophytic fungi to biotransform the chiral drug IBP into its metabolites. Resolution of IBP and the stereoisomers of its main metabolites was achieved by use of a Chiralpak AS-H column (150 × 4.6 mm, 5 μm particle size), column temperature 8 °C, and the mobile phase hexane–isopropanol–trifluoroacetic acid (95: 5: 0.1, v/v) at a flow rate of 1.2 mL min⁻¹. Post-column infusion with 10 mmol L⁻¹ ammonium acetate in methanol at a flow rate of 0.3 mL min⁻¹ was performed to enhance MS detection (positive electrospray ionization). Liquid–liquid extraction was used for sample preparation with hexane–ethyl acetate (1:1, v/v) as extraction solvent. Linearity was obtained in the range 0.1–20 μg mL⁻¹ for IBP, 0.05–7.5 μg mL⁻¹ for each 2-OH-IBP enantiomer, and 0.025–5.0 μg mL⁻¹ for each COOH-IBP stereoisomer (r ≥ 0.99). The coefficients of variation and relative errors obtained in precision and accuracy studies (within-day and between-day) were below 15%. The stability studies showed that the samples were stable (p > 0.05) during freeze and thaw cycles, short-term exposure to room temperature, storage at −20 °C, and biotransformation conditions. Among the six fungi studied, only the strains Nigrospora sphaerica (SS67) and Chaetomium globosum (VR10) biotransformed IBP enantioselectively, with greater formation of the metabolite (+)-(S)-2-OH-IBP. Formation of the COOH-IBP stereoisomers, which involves hydroxylation at C3 and further oxidation to form the carboxyl group, was not observed.     

High-pressure phase equilibria for the carbon dioxide–2-methyl-1-butanol,carbon dioxide–2-methyl-2-butanol,carbon dioxide–2-methyl-1-butanol–water,and carbon dioxide–2-methyl-2-butanol–water systems

High-pressure vapor–liquid equilibria for the binary carbon dioxide–2-methyl-1-butanol and carbon dioxide–2-methyl-2-butanol systems were measured at 313.2 K. The phase equilibrium apparatus used in this work is of the circulation type in which the coexisting phases are recirculated, on-line sampled, and analyzed. The critical pressure and corresponding mole fraction of carbon dioxide for the binary carbon dioxide–2-methyl-1-butanol system at 313.2 K were found to be 8.36 MPa and 0.980, respectively. The critical point of the binary carbon dioxide–2-methyl-2-butanol was also found 8.15 MPa and 0.970 mole fraction of carbon dioxide. In addition, the phase equilibria of the ternary carbon dioxide–2-methyl-1-butanol–water and carbon dioxide–2-methyl-2-butanol–water systems were measured at 313.2 K and several pressures. These ternary systems showed the liquid–liquid–vapor phase behavior over the range of pressure up to their critical point. The binary equilibrium data were all reasonably well correlated with the Redlich–Kwong (RK), Soave–Redlich–Kwong (SRK), Peng–Robinson (PR), and Patel–Teja (PT) equations of state with eight different mixing rules the van der Waals, Panagiotopoulos–Reid (P&R), and six Huron–Vidal type mixing rules with UNIQUAC parameters.     

免疫亲和柱高效液相色谱法快速测定牛奶和奶粉中黄曲霉毒素M1、B1、B2、G1、G2

采用单克隆抗体免疫亲和技术作为直接从样品中分离提取黄曲霉毒素的特效手段,提取液挥干后,经衍生用HPLC荧光检测器测定.对鲜奶和高脂奶粉(脂肪含量25%)在0.01,0.05,0.1和0.1,0.5,1.0 μg·L-1水平对黄曲霉毒素M1、B1、B2、G1、G2测定平均回收率(n=10)为66.0%～97.0%;相对标准偏差(n=10)为1.04%～14.0%.方法的检出限低于0.01 μg·L-1(鲜奶), 0.1 g·kg-1(奶粉).     

Determination of 5-Hydroxytryptamine, Norepinephrine, Dopamine and Their Metabolites in Rat Brain Tissue by LC–ESI–MS–MS

A liquid chromatography–electrospray ionization tandem mass spectrometry method has been developed to perform the determination of 5-hydroxytryptamine (5-HT), norepinephrine (NE), dopamine (DA) and their metabolites, i.e., 5-hydroxyindole-3-acetic acid (5-HIAA), 4-hydroxy-3-methoxyphenylglycol (MHPG) sulfate, 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA) in rat brain tissue. Analytes were separated on a Thermo C₁₈ column (4.6 mm × 250 mm, 5 μm, SN: 1245575T, Thermo electron corporation, USA) with a mobile phase of 0.05% formic acid/acetonitrile (92:8 for ESI⁺, 82:18 for ESI^?, v/v) at the flow-rate of 0.8 mL min^?1. The LC system was coupled to a Waters Micromass Quattro Premier XE tandem quadruple mass spectrometer. MS acquisition of 5-HT, NE and DA was performed in positive electrospray ionization multiple reaction monitoring (MRM) mode, while negative electrospray ionization MRM mode was used to monitor their metabolites. The calibration curves were linear within the concentration range of 4–4,450 ng mL^?1 for 5-HT, 4–4,110 ng mL^?1 for NE and 4–4,100 ng mL^?1 for DA (r ≥ 0.999). The limit of quantitation was 4 ng mL^?1. 5-HIAA, MHPG, DOPAC and HVA have good linearity within the range of 12–1,000 ng mL^?1(r ≥ 0.998) and the limit of quantitation was 12 ng mL^?1. The intra- and inter-day RSD were lower than 8.45%. The method is sensitive, fast, accurate and usable for quantity determination of monoamine neurotransmitters and their metabolites in neuropsychiatric diseases.     

LC–MS/MS法检测黑色粮谷类食品中的苏丹黑B和苏丹红B

采用液相色谱串联质谱(LC–MS/MS)法测定黑色粮谷类食品中苏丹黑B和苏丹红B含量。用正己烷、饱和乙腈提取目标物,以乙腈饱和的正己烷去除油脂,以固相萃取柱富集净化处理,外标法定量。苏丹黑B和苏丹红B的质量浓度在5~100 ng/m L范围内与色谱峰面积呈良好的线性,线性相关系数r20.999,检出限为5μg/kg。加标回收率为90.0%~96.0%,测定结果的相对标准偏差小于1.0%(n=6)。该方法分析时间短,准确性好,适用于黑色粮谷类食品中苏丹黑B和苏丹红B含量的检测分析。     

Simultaneous Determination of Fluoroquinolones, Tetracyclines and Sulfonamides in Chicken Muscle by UPLC–MS–MS

A rapid and sensitive analytical method for the simultaneous determination of four fluoroquinolones, four tetracyclines and six sulfonamides in chicken muscle using ultra-performance liquid chromatography coupled to tandem mass spectrometry (UPLC–MS–MS) has been developed and validated. Samples were extracted with McIlvaine buffer-acetonitrile, defatted with n-hexane, and analyzed by UPLC–MS–MS. Solvent delay technique was applied in the analysis to remove the non-volatile phosphate and carry out farther on-line SPE clean-up. Satisfactory recoveries (55–110%) of all the veterinary drugs were demonstrated in 1, 10 and 20 μg kg^?1 spiked levels with the overall RSD for intra- and inter-day of 14 analytes less than 18%. The LOD and LOQ were 0.3 and 1.0 μg kg^?1, respectively. Quantitative results of 103 real samples indicated that the present method was suitable for the quantitative analysis of real samples.     

固相萃取-高效液相色谱/串联质谱检测谷物中黄曲霉毒素B1、B2、G1、G2和M1

建立了高效液相色谱/串联质谱(LC-MS/MS)同时检测谷物中的黄曲霉毒素B1、B2、G1、G2和M1的方法.并优化了液相色谱条件和质谱的相关参数.谷物样品经研磨成粉末后,直接经甲醇-水( V∶V=10∶90)提取,Oasis HLB固相萃取净化,乙腈-水(0.2％甲酸)梯度洗脱,选择电喷雾离子源(ESI),正离子扫描...     

Simultaneous measurement of endogenous cortisol,cortisone, dehydroepiandrosterone,and dehydroepiandrosterone sulfate in nails by use of UPLC–MS–MS

Steroid hormone concentrations are mostly determined by using different body fluids as matrices and applying immunoassay techniques. However, usability of these approaches may be restricted for several reasons, including ethical barriers to invasive sampling. Therefore, we developed an ultra-performance LC–MS–MS method for high-throughput determination of concentrations of cortisol, cortisone, dehydroepiandrosterone (DHEA), and DHEA sulfate (DHEAS) in small quantities of human nails. The method was validated for linearity, limits of detection and quantification, recovery, intra and interassay precision, accuracy, and matrix effect. Samples from 10 adult women were analyzed to provide proof-of-principle for the method’s applicability. Calibration curves were linear (r ² > 0.999) in the ranges 10–5000 pg mg⁻¹ for cortisol, cortisone, and DHEAS, and 50–5000 pg mg⁻¹ for DHEA. Limits of quantification were 10 pg mg⁻¹ for cortisol, cortisone, and DHEAS, and 50 pg mg⁻¹ for DHEA. The sensitivity and specificity of the method were good, and there was no interference with the analytes. Mean recovery of cortisol, cortisone, DHEA, and DHEAS was 90.5%, 94.1%, 84.9%, and 95.9%, respectively, with good precision (coefficient of variation <14% for all analytes) and accuracy (relative error (%) −8.3% to 12.2% for all analytes). The median (pg mg⁻¹, range) hormone concentrations were 69.5 (36–158), 65 (32–133), 212 (50–1077), and 246 (115–547) for cortisol, cortisone, DHEA, and DHEAS, respectively. This method enables measurement of cortisol, cortisone, DHEA, and DHEAS in small quantities of human nails, leading to the development of applications in endocrinology and beyond.     

LC–MS–MS Determination of Nikethamide in Human Plasma

A sensitive LC–MS–MS method with electrospray ionization has been developed for determination of nikethamide in human plasma. After addition of atropine as internal standard, liquid–liquid extraction was used to produce a protein-free extract. Chromatographic separation was achieved on a 150 mm × 2.1 mm, 5 μm particle, Agilent Zorbax SB-C₁₈ column, with 45:55 (v/v) methanol–water containing 0.1% formic acid as mobile phase. LC–MS–MS was performed in multiple reaction monitoring mode using target fragment ions m/z 178.8 → 107.8 for nikethamide and m/z 289.9 → 123.8 for the internal standard. Calibration plots were linear over the range of 20.0–2,000 ng mL^?1. The lower limit of quantification was 20.0 ng mL^?1. Intra-day and inter-day precisions were better than 4.2 and 6.1%, respectively. Mean recovery of nikethamide from human plasma was in the range 65.3–71.1%.