超高效液相色谱-串联质谱法快速测定纺织品和皮革中偶氮染料释放的致癌芳香胺

建立了超高效液相色谱-串联质谱法(UHPLC-MS/MS)快速测定纺织品和皮革中偶氮染料释放的致癌芳香胺物质的方法。样品前处理采用BS EN 14362-1:2012(纺织品)和ISO 17234-1:2010(皮革)方法,然后采用甲醇定容,再用Eclipse XDB-C18 RRHD色谱柱进行梯度洗脱分离,流动相为甲醇和水;采用电喷雾正离子模式,并用多反应监测模式(MRM)测定,外标法定量。方法优化了色谱分离条件、质谱碎裂电压、碰撞能量等,并考察了不同样品基质对回收率的影响。方法的定量限小于0.2 mg/kg;不同基质不同浓度的加标回收率在70%～120%之间(添加水平为500、1000、1500 μg/L, n=7);相对标准偏差小于15%。该方法的灵敏度远小于欧盟与我国国家标准要求的30 mg/kg,完全满足其定性定量的检测要求,并且检测速度快,选择性好。     

顺序注射固定化酶化学发光法在线检测甲醇酵母发酵液中的甲醇

运用顺序注射分析技术,完成了样品的在线预处理,并采用固定化酶化学发光检测法测定甲醇的浓度,建立了一种在线监测甲醇酵母发酵诱导阶段发酵液中甲醇浓度的新方法。在选定的最佳条件下,甲醇浓度在0%～1.0%(V/V)范围内与化学发光强度呈良好的线性关系(R=0.9995),相对标准偏差(RSD)为1.9%(n=11),72 h内RSD为5.0%(0.2%甲醇溶液)。该法可在线自动完成过滤、稀释、测定等操作,分析速度快,长期稳定性高,能满足在线监测甲醇酵母发酵液中甲醇浓度的要求。     

皮革和纺织品中重叠峰偶氮染料的气相色谱-串联质谱检测技术

建立了气相色谱-串联质谱一次进样同时检测重叠峰偶氮染料的分析方法.皮革和纺织品中的偶氮染料用柠檬酸盐缓冲液提取,再用连二亚硫酸钠将其还原裂解为胺类物质,经液-液萃取、浓缩处理,所得残渣用甲醇溶解,通过VF-5ms色谱柱分离,采用串联质谱的多反应监测模式开设多通道存储子离子信息,进行定性、定量分析.实验结果表明:优化质谱分析条件后,气相色谱一串联质谱可进一步消除杂质干扰,分离共流出组分.大部分芳香胺3种浓度水平的加标回收率(n=6)保持在71%～94%之间,检测限为0.008～0.672μg/mL(S/N=3),相对标准偏差(n=6)小于11%,2～50μg/mL浓度范围内线性相关系数大于0.9917,满足禁用偶氮染料的分析要求.     

同步荧光光谱法测定蛋白质

在模拟生理条件下,由于核苷类药物中间体氰基乙基尿嘧啶(CEU)与血清白蛋白相互作用,血清白蛋白的内源荧光发生特异性变化,且体系的同步荧光强度和溶液中血清白蛋白的浓度呈线性关系,据此提出以氰基乙基尿嘧啶为探针,用固定波长同步荧光光谱法测定人血清白蛋白(HSA)和牛血清白蛋白(BSA)的方法.在最佳试验条件下,体系的荧光强度与HSA和BSA的质量浓度分别在1.38～496.2 mg·L-1和1.56～624.0 mg·L-1范围内呈线性关系,检出限(3S/N)分别为0.045 mg·L-1和0.051 mg·L-1.方法应用于人血清及牛血清中HSA及BSA的测定,并以此样品为基体分别加入HSA及BSA标准溶液作回收试验,测得回收率在95.1%～102.5%之间,相对标准偏差(n=6)在0.43%～2.72%之间.     

挥发化合物发生-原子荧光法测定水中痕量锌

研究了挥发化合物发生-原子荧光光谱法测定环境水中痕量锌的可行性,着重优化了硼氢化钾与锌的反应条件,包括仪器和试剂条件.研究发现:适量镍离子和钴离子的存在能增强锌的荧光强度.在选定的最佳试验条件下,荧光强度与锌的质量浓度在0～1 200μg·L-1范围内呈线性关系.对标准空白进行11次测定,方法检出限为0.53μg·L-1;对400μg·L-1锌进行11次测定,其相对标准偏差(RSD)为3.0%,平行测定8份水样,RSD为3.6%;分析了4种不同水样并做加入不同浓度锌(Ⅱ)标准溶液时的回收率试验,结果在98%～104%之间.     

免疫亲和柱净化/高效液相色谱-串联质谱法检测婴幼儿配方乳粉中生物素含量

建立了免疫亲和柱净化/高效液相色谱串联质谱法测定婴幼儿配方乳粉中生物素的方法。样品用磷酸盐缓冲液溶解,并通过生物素免疫亲和柱净化后,采用Ultimate AQ-C18(2.1 mm×100 mm,3μm)色谱柱分离,以甲醇-0.1%甲酸(30∶70)为流动相,进样量为5.0μL,流速为0.3 mL/min,柱温为30℃,并经电喷雾电离串联质谱在多离子反应监测(MRM)模式下进行测定,定量子离子为227.2,定性子离子为227.2、96.9,碰撞能量分别为10、30 V。结果显示,生物素在0.1~1.0μg/mL范围内线性关系良好,方法检出限为20.3μg/kg。对空白试样进行3个浓度水平的加标回收实验,测得加标回收率为92.7%~98.5%,相对标准偏差为1.7%~1.9%。该方法具有样品处理简单、灵敏度高、重现性好、分析时间短等优点,可以满足婴幼儿配方乳粉中生物素含量的测定要求。     

超高效液相色谱-质谱联用测定维生素预混合饲料中生物素含量

建立了维生素预混合饲料中生物素含量的超高效液相色谱质谱联用测定方法。样品用水提取后以Acquity UPLC BEH C18柱(2.1×50mm,1.7μm)为色谱柱分离,以电喷雾电离串联质谱在正离子选择反应监测(SRM)模式下进行测定。以V(乙腈)∶V(0.1%甲酸)=15∶85为流动相,流速为0.2mL/min,色谱柱温度为40℃,进样量为2μL;定量子离子为227.1,定性子离子为227.1、97.1、123.0,二级碰撞室内对应的碰撞能量分别为:11、22、37V。对空白试样进行3个浓度水平4个重复的添加试验。结果表明:回收率78.2%～93.2%,相对标准偏差1.5%～2.8%。该方法检测限0.2mg/kg,线性范围0.010～5.000μg/mL。     

紫外光谱法测定饮料中的咖啡因含量

建立了一种测定饮料中咖啡因含量的紫外光谱分析法.采用三氯甲烷为萃取剂,控制三氯甲烷与饮料的体积比为8:1,经充分振荡后离心分离,取清液在276 nm处测定紫外吸收光谱,能够满意地测定市售饮料中的咖啡因浓度.分析结果的相对标准偏差小于4%;在饮料中加入不同浓度的咖啡因标准溶液,回收率在94.0%～112.0%之间.     

超高效液相色谱-四极杆-飞行时间高分辨质谱用于乳液类化妆品中9种抗过敏违禁药物的筛查和定量分析

建立了超高效液相色谱-四极杆-飞行时间高分辨质谱(UPLC-Q-TOF-HRMS)快速筛查和定量检测乳液类化妆品中9种抗过敏违禁药物的方法。乳液样品经乙腈涡旋和超声提取,采用PRiME HLB固相萃取小柱净化,以0.1%甲酸水-乙腈为流动相在XBridge C18色谱柱上进行梯度洗脱和分离,采用电喷雾电离源,在正离子模式下采用全景式数据非依赖性扫描模式(SWATH)进行数据采集,结合保留时间、母离子精确质量数、同位素峰及二级子离子碎片进行快速定性筛查,采用特征子离子碎片的峰面积进行外标法定量。实验比较了不同仪器条件和前处理条件对乳液类样品中9种抗过敏物质测定的影响,并对比了不同级别离子定量对基质效应的影响。结果表明,较其他净化柱而言,PRiME HLB固相萃取小柱具有更好的净化效果,能降低杂质对目标峰的干扰,同时保证目标物的回收;在优化的条件下,9种抗过敏药物在5~100 μg/L质量浓度范围内线性良好,相关系数(r²)均大于0.99; 9种目标物的定量限在0.05~0.10 mg/kg之间;在3个添加水平(0.10、0.20和0.60 mg/kg)下,其回收率在65.3%~107%之间,相对标准偏差(RSD, n=6)均小于20%;基质效应实验结果表明,采用二级子离子定量能够降低基质效应,提高定量准确度。与文献方法相比,该法操作简便,前处理耗时更短,其高精度质量数和二级指纹图谱比对技术能保证检测结果的准确度和灵敏度,可实现乳液类化妆品中抗过敏违禁药物的快速筛查和准确定量。     

氢化物发生-原子荧光光谱法测定黄磷中微量砷

采用氢化物发生-原子荧光光谱法测定黄磷中微量砷,研究了样品消化方法以及仪器工作条件、还原剂等对测定的影响,确定了最佳试验条件.在最佳试验条件下,荧光强度与砷(Ⅲ)的质量浓度在0.06～10μg·L-1范围内呈线性关系,相关系数为0.999 4,检出限为0.03μg·L-1,样品分析结果的相对标准偏差小于3.5 %,加标回收率在93.80～103.6%之间.     

Are liquid chromatography/electrospray tandem quadrupole fragmentation ratios unequivocal confirmation criteria?

Multiple reaction monitoring (MRM) ratios as provided by tandem mass spectrometers are used to confirm positive residue findings (e.g. veterinary drugs or pesticides). The Commission Decision 2002/657/EEC defines tolerance levels for MRM ratios, which are intended to prevent the reporting of false positives. This paper reports findings where blank sample extracts have been spiked by a drug (difloxacin) and the corresponding measured MRM ratios significantly deviated from MRM ratios observed in matrix‐free solution. The observation was explained by the formation of two different [M+H]⁺ analyte ions within the electrospray ionization (ESI) interface. These two ions vary only by the site of analyte protonation. Since they are isobaric, they are equally transmitted through the first quadrupole, but are differently fragmented in the collision chamber. The existence of two isobaric ions was deduced by statistical data and the observation of a doubly charged analyte ion. It was hypothesized that the combined presence of [M+H]⁺ and [M+2H]²⁺ implies the existence of two different singly charged ion species differing only by the site of protonation. Low‐ and high‐energy interface‐induced fragmentation was performed on the samples. The surviving precursor ion population was mass selected and again fragmented in the collision chamber. Equal product ion spectra would be expected. However, very different product ion spectra were observed for the two interface regimes. This is consistent with the assumption that the two postulated isobaric precursor ions show different stability in the interface. Hence the abundance ratio among the two types of surviving precursor ions will shift and change the resulting product ion spectra. The existence of the postulated singly charged ions with multiple chargeable sites was finally confirmed by successful ion mobility separation. Copyright © 2009 John Wiley & Sons, Ltd.     

Evaluation of serum as a potential matrix for multiresidue determination of fluoroquinolone antibiotics in chicken using liquid chromatography-fluorescence-mass spectrometry(n)

An efficient multiresidue method was successfully applied to the determination of fluoroquinolones (FQs) in chicken serum. In this method, FQs are extracted from matrix with ammoniacal acetonitrile, and the extracts are defatted and then evaporated. After addition of basic phosphate buffer and filtration, the samples are analyzed by liquid chromatography-fluorescence-mass spectrometry(n) (multiple mass spectrometry; MS(n)). This approach allows for simultaneous quantitation (fluorescence) and confirmation (MS(n)) of the FQs. Using this method, 8 FQs were determined in fortified chicken serum at levels of 10, 20, 50, and 100 ng/g. Recoveries ranged from 71-99%, with excellent relative standard deviations (< 10%). Limits of quantitation for the FQs ranged from 0.05-5 ng/g. Confirmation was achieved by comparison of MS2 or MS3 product ion ratios with those of standard FQ samples. These quantitative and confirmatory results were compared with those obtained for muscle using this approach. Serum and muscle samples from enrofloxacin-dosed chickens were also analyzed with this method. The results show that enrofloxacin can be determined in both serum and muscle of chickens dosed at a level formerly approved by the U.S. Food and Drug Administration, for up to at least 48 h after withdrawal from dosing, and suggest that serum can provide an efficient matrix for monitoring FQ levels in chicken.     

Ultra‐performance liquid chromatography/tandem mass spectrometry in high‐throughput detection,quantification and confirmation of anabolic steroids in equine plasma

An ultra‐performance liquid chromatography/tandem mass spectrometry (UPLC/MS/MS) method for fast‐throughput analysis of eight anabolic and androgenic steroids (AAS) in equine plasma is reported. Analytes were recovered by liquid‐liquid extraction using methyl tert‐butyl ether, separated on a 1.9 µm C₁₈ reversed‐phase column, and analyzed in positive electrospray ionization mode on a triple quadrupole mass spectrometer with selected reaction monitoring (SRM) and full product ion scans. Two SRM ion transitions were monitored for each AAS during screening to obtain highly selective screening results. Full product ion spectra of excellent quality for AAS, at 100 pg/0.5 mL in plasma, devoid of interfering spectra from impurities in plasma, were obtained. To our knowledge, this is the first report on the acquisition of full product ion spectra at such a low analyte concentration and plasma volume using a triple quadrupole instrument. In addition to product ion intensity ratios obtained from three SRM scans for identifying AAS in equine plasma, full product ion spectra were used as supporting evidence for confirmation. For quantification, deuterium‐labeled testosterone and stanozolol were used as internal standards (ISs). The limits of detection, quantification and confirmation were 6.25–12.5 pg/0.5 mL, 25 pg/0.5 mL and 50–100 pg/0.5 mL, respectively. There was no significant matrix effect on the analysis of all eight AAS. Intra‐day precision and accuracy were 2–15% and 91–107%, respectively. Inter‐day precision and accuracy were 1–21% and 94–110%, respectively. Total analysis time was 5 min. To date, the method has been successfully used in the analysis of >12 000 samples for AAS in plasma samples from racehorses competing in the State of Pennsylvania. The method is fast, selective, reproducible, and reliable. Copyright © 2009 John Wiley & Sons, Ltd.     

Determination of Perfluorochemicals in Human Milk Using Isotope‐dilution Liquid Chromatography Tandem Mass Spectrometry

A highly precise and accurate analytical method utilizing an isotope‐dilution liquid chromatography tandem mass spectrometry was developed and validated to determine two perfluorochemicals (PFCs): perfluorooctanoate (PFOA) and perfluorooctanesulfonate (PFOS) in human milk samples. Identification of the analytes was confirmed under negative electrospray with multiple reaction monitoring (MRM) mode by the monitoring of one precursor ion and two product ions, and matching of relative ion intensities of the ions concerned in samples and calibration standards. Quantitation was based on the measurement of concentration ratios of the natural and labeled‐analogues in the samples and calibration mixtures. The isotope‐labeled internal standards were also used to correct the matrix effect and variations associated with the analysis. Intra‐ and inter‐day repeatabilities of replicate analyses of the PFOA and PFOS in milk samples were below 8%. The limit of quantitation was 2 pg/mL in a 5 mL milk sample. The PFOA and PFOS were detected in all 20 human milk samples at concentrations from 27.0 to 207 pg/mL. This is the first study to measure the occurrence of PFOA and PFOS in human milk from Taiwan.     

Liquid chromatography/electrospray ionization tandem mass spectrometry for the quantification of mitiglinide in human plasma: validation and its application to pharmacokinetic studies

A sensitive and specific method was developed and validated for the determination of mitiglinide in human plasma using liquid chromatographic separation with electrospray ionization tandem mass spectrometric detection. Acidified plasma samples were extracted with ethyl acetate. The chromatographic separation was performed on an Agilent Zorbax Eclipse Plus C(18) column with a mobile phase of methanol-10 mm ammonium acetate solution at a flow rate of 0.3 mL/min. Analytes were detected with an Agilent 6410 Triple qudrupole mass spectrometer equipped with an electrospray ionization source in positive multiple reaction monitoring mode: m/z 316.2 (precursor ion) to 298.2 (product ion) for mitiglinide and m/z 318.2 (precursor ion) to 120.2 (product ion) for the internal standard. This method was validated over a linear range of 0.5-4000 ng/mL for mitiglinide in human plasma. The lower limit of quantification (LLOQ) was 0.5 ng/mL, while a relative standard deviation (RSD) was less than 3.9%. The intra- and inter-run precision (as RSD, %) obtained from three validation runs were all less than 15%. The validated method was successfully used to analyze human plasma samples for application in pharmacokinetic studies.     

Determination of long-acting release octreotide, an octapeptide analogue of somatostation, in human plasma by liquid chromatography/tandem mass spectrometry

A sensitive and selective method for the determination of long-acting released octreotide in human plasma has been developed based on liquid chromatography/tandem mass spectrometry (LC/MS/MS). Octreotide and the internal standard, triptorelin, were precipitated from the matrix, washed with dichloromethane and subsequently separated by reversed-phase high-performance liquid chromatography (HPLC) employing a 1% formic acid/methanol gradient system. Detection was by electrospray ionization mass spectrometry in the positive ion mode using multiple-reaction monitoring. The assay was linear in the concentration range 0.0500-50.0 ng/mL with intra- and inter-day precision (as relative standard deviation) of <2.95% and <8.37%, respectively. The limit of detection was 0.0200 ng/mL. The method was applied to a pharmacokinetic study of long-acting released octreotide in healthy volunteers given an intramuscular injection containing 20 mg octreotide.     

Development and validation of a high‐performance liquid chromatography–tandem mass spectrometric method for simultaneous determination of bupropion,quetiapine and escitalopram in human plasma

In the present study, an effective high performance liquid chromatography–tandem mass spectrometric (HPLC/MS/MS) method was developed and validated to simultaneously determine bupropion (BUP), quetiapine (QUE) and escitalopram (ESC) in human plasma using carbidopa as the internal standard. Chromatographic separation was achieved on a Waters Sun Fire C₁₈ column using reversed‐phase chromatography. The MS/MS experiment was performed in positive ion multiple reaction monitoring mode to produce product ions of m/z 240.3 → 184.2 for BUP, 384.2 → 253.1 for QUE, 325.3 → 109.3 for ESC and 227.2 → 181.2 for the internal standard. The method showed good linearity (R² ≥ 0.997), precision (relative standard deviation ≤7.5%), satisfactory intra‐ and interday accuracy (88.4–113.0%) and acceptable extraction recovery (87.2–115.0%), matrix effect (84.5.5?108.7%) and stability (92.3?103.5%). The method was successfully applied to determine the concentrations of BUP, QUE and ESC in human plasma samples. Copyright © 2014 John Wiley & Sons, Ltd.     

A liquid chromatography/tandem mass spectrometry method for determination of aristolochic acid‐I in rat plasma

A sensitive, rapid and specific liquid chromatography–electrospray ionization–tandem mass spectrometry method was developed and validated for the determination of aristolochic acid‐I (AA‐I) in rat plasma. Finasteride was used as the internal standard (IS). The analyte was separated on a Zorbax Eclipse XDB‐C₁₈ column by isocratic elution with methanol‐10 mM ammonium acetate (75:25, v/v, pH = 7.3) at a flow rate of 0.25 mL/min, and analyzed by mass spectrometry in positive multiple reaction monitoring mode. The precursor‐to‐product ion transitions of m/z 359.0 → 298.2 and m/z 373.1 → 305.2 were used to detect AA‐I and IS, respectively. Good linearity was achieved over a range of 0.4–600 ng/mL. Intra‐ and inter‐day precisions measured as relative standard deviation were less than 13.5%, and accuracy ranged from 94.2 to 97.5%. The developed method was successfully applied in the pharmacokinetic study of AA‐I in rats. Copyright © 2009 John Wiley & Sons, Ltd.     

Pharmacokinetic studies of a novel tubulin inhibitor SK1326 in rat plasma by UPLC–MS/MS

A sensitive method for quantitation of SK1326 in rat plasma has been established using ultra-performance liquid chromatography–electrospray ionization tandem mass spectrometry (UPLC–ESI/MS/MS). SK1326 and the internal standard (tramadol) in plasma sample were extracted using acetonitrile. A centrifuged upper layer was then evaporated and reconstituted with a mobile phase of 0.5% formic acid–acetonitrile (35:65, v/v). The reconstituted samples were injected into a C₁₈ reversed-phase column. Using MS/MS in the multiple reaction monitoring mode, SK1326 and tramadol were detected without severe interference from the rat plasma matrix. SK1326 produced a protonated precursor ion ([M + H]⁺) at m/z 432.3 and a corresponding product ion at m/z 114.4. The internal standard produced a protonated precursor ion ([M + H]⁺) at m/z 264.4 and a corresponding product ion at m/z 58.1. Detection of SK1326 in rat plasma by the UPLC–ESI/MS/MS method was accurate and precise with a quantitation limit of 1.0 ng/mL. The validation, reproducibility, stability and recovery of the method were evaluated. The method has been successfully applied to pharmacokinetic studies of SK1326 in rat plasma. The pharmacokinetic parameters of SK1326 were evaluated after intravenous (at a dose of 10 mg/kg) and oral (at a dose of 20 mg/kg) administration of SK1326 in rats. After oral administration (20 mg/kg) of SK1326, the F (fraction absorbed) value was ~77.1%.     

Stability evaluation of alkali metal standard solutions by using precise ion chromatography

Mass fractions of alkali metal (Li, Na, K, Rb, Cs) standard solutions (1000 mg/kg) were measured with about 0.1% relative standard deviation by improving the method of injection in ion chromatography (IC). This technique was applied to stability testing of the standard solutions. After storage of each alkali metal standard solution for 18 months, an increase of the mass fraction was observed, for all the alkali metal ions, of approximately 0.15% per year at 25 °C and approximately 0.02% per year at 5 °C. The observed increase of the mass fraction can be explained by the weight loss of the solution during storage. The deviation between the mass fraction measured by IC and the preparation mass fraction after correcting the weight loss for solvent evaporation was within ±0.05% for every alkali metal ion. It is concluded that alkali metal standard solutions of 1000 mg/kg are basically stable for more than 18 months under these storage conditions and that correction for evaporation is effective if weight monitoring of each bottle is performed precisely. Presented at BERM-11, October 2007, Tsukuba, Japan.