同位素稀释液相色谱串联质谱法测定血清葡萄糖

目的 建立一种使用同位素稀释液相色谱串联质谱法(ID-LC/MS/MS)测定血清葡萄糖的候选参考方法.方法 以[~(13)C_6]葡萄糖为内标,用重量法准确地与血清混合,除去蛋白后在碱性条件下与1-苯基-3-甲基-5-吡唑酮反应,用LC/MS/MS测定葡萄糖和内标衍生产物,以包括法定量.结果 血清葡萄糖测定的批内、批间和总变异系数的平均值分别为0.36%(范围0.28%-0.42%)、0.47%(范围0.20%-0.67%)和0.61%(范围0.42%-0.76%).加样回收试验的回收率范围为99.0%-100.9%.分析参考物质SRM 965a,测定结果与认定值的平均偏差为-0.20%(范围-0.39%-+0.11%).结论 建立了ID-LC/MS/MS法测定血清葡萄糖的方法,方法准确、精密、简便,可望作为血清葡萄糖测定的参考方法.     

同位素稀释液相色谱串联质谱法测定血清肌酐

目的 建立一种使用同位素稀释液相色谱串联质谱法(ID-LC/MS/MS)测定血清肌酐的候选参考方法.方法 以[2H3]肌酐为内标,用无水乙醇沉淀血清中的蛋白质,用氯仿纯化上清液,用液相色谱串联质谱分离测定,以包括法定量.结果 血清肌酐测定的批内、批间和总变异系数的平均值分别为0.57%(范围0.52%～0.61%)、0.43%(范围0.11%～0.59%)和0.73%(范围0.62%～0.83%).加样回收试验的回收率范围为99.09%～101.13%.分析两种参考物质SRM909b和SRM 967b,测定结果与认定值的偏差小于0.4%.结论 建立了ID-LC/MS/MS法测定血清肌酐的方法,方法准确、精密、简便,可望作为血清肌酐测定的参考方法.     

同位素稀释液相色谱串联质谱法测定血清睾酮

目的建立一种用同位素稀释液相色谱串联质谱法(ID-LC/MS/MS)测定血清睾酮的候选参考方法。方法以[16,17,17-d3]睾酮为内标,用重量法准确地与血清混合,用乙酸乙酯-正己烷混合溶剂提取,以羟丙基-β-环糊精水溶液对提取液作净化处理,用液相色谱串联质谱分析,质谱选择离子监测模式检测睾酮与内标的特定碎片离子,用包括法定量。结果血清睾酮测定的批内、批间和总变异系数(CV)的均值(范围)为0.84%(0.22%~2.00%)、1.01%(0.48%~2.37%)和1.37%(0.53%~3.09%)。参考物质ERM DA-345a和NIST SRM 971测定结果与认定值的平均偏差范围为-2.0%~+1.8%。结论用ID-LC/MS/MS建立了血清睾酮的测定方法,方法准确、精密、简便,有望作为血清睾酮测定的参考方法。     

基于液相色谱串联质谱技术对血清同型半胱氨酸常规检测系统的正确度评价

目的以同位素稀释液相色谱串联质谱(ID-LC/MS/MS)为比对方法,评价酶循环法测定血清同型半胱氨酸(Hcy)的正确度。方法采用ID-LC/MS/MS和酶循环法同时检测20份新鲜单人份血清中的Hcy浓度,对测定结果进行方法学比对和评价。采用ID-LC/MS/MS和酶循环法同时测定5个水平的工作校准品,根据比对结果调整酶循环法校准品值,直至酶循环法的测定结果与比对方法的测定结果一致。结果采用ID-LC/MS/MS检测SRM 1950标准物质,测定结果与证书标示值一致,相对偏移1.0%。酶循环法与ID-LC/MS/MS的线性拟合方程为Y=1.204 1X+0.364 6(r~2=0.987 9),平均偏移为24.0%。调整后的酶循环法与ID-LC/MS/MS的线性拟合方程为Y=0.988 6X+0.260 3(r~2=0.999 7),平均偏移为-0.09%。结论 ID-LC/MS/MS能准确测定血清Hcy水平,或许可作为Hcy常规检测系统正确度评价的比对方法。     

同位素稀释液相色谱串联质谱法测定血清总甘油

目的 建立同位素稀释液相色谱串联质谱测定血清总甘油的方法.方法 以[13C3]-甘油作内标,用氢氧化钾异丙醇溶液水解血清甘油酯为游离甘油,将游离甘油转化为苯甲酸酯,用同位素稀释液相色谱串联质谱(LC/MS/MS)分离检测,用标准曲线法定量.结果 甘油/内标峰面积比与甘油浓度(0.565～4.517 mmol/L)线性相关系数大于0.999 9;测定不同浓度血清总甘油批内变异系数(CV)平均为0.52%(范围0.21%～2.62%),总CV平均为1.15%(范围0.62%～2.00%);分析国际和国家标准物质,测定值与认证值的偏倚小于1%(-0.20%～1.06%).结论 建立同位素稀释液相色谱串联质谱测定血清总甘油方法,方法特异、精密、准确,可望用作血清总甘油测定参考方法.     

人血浆中血管紧张素Ⅱ候选参考方法的建立

目的建立用同位素稀释液相色谱串联质谱(ID-LC/MS/MS)测定人血浆中血管紧张素Ⅱ的候选参考方法, 并对方法性能进行评价。方法以[13C6-15N]-血管紧张素Ⅱ为内标, 重量法准确称取血浆及一定量内标混合, 同时加入酶抑制剂, 经硫酸锌溶液蛋白沉淀、反相固相萃取板处理, 用液相色谱串联质谱分析, 质谱选择多反应离子监测模式检测血管紧张素Ⅱ及内标的特定离子碎片。按照ISO15193要求对所建方法进行线性、灵敏度、精密度、回收率等性能评估及不确定度的评价。结果血管紧张素Ⅱ在10～1 000 pg/g范围内线性良好(r=0.999 5), 检测下限7.68 pg/g, 加标回收率范围为97.14%～102.85%, 批内不精密度≤3.21%, 批间不精密度≤2.96%, 总不精密度≤3.67%。结论用同位素稀释液相色谱串联质谱建立了血浆血管紧张素Ⅱ的检测方法, 该方法准确可靠, 有望成为血浆中血管紧张素Ⅱ测定的参考方法。     

同位素稀释质谱法在美国CDC-CRMLN计划中的比对结果分析

目的总结并回顾性分析同位素稀释质谱法在美国疾病预防控制中心(CDC)胆固醇参考方法实验室网络(CRMLN)中的比对结果,为我国血脂测定提供质量保证。方法采用我国建立的同位素稀释液相色谱串联质谱(ID-LC/MS/MS)测定血清总胆固醇(TC)和三酰甘油(TG)的方法参加CRMLN比对。2016年之前每3个月1次,每次4种样品,测定2批。2016年之后每半年比对1次,每次4种样品,测定2批。每次测定中至少同时测定2个有证标准物质作为质控品。结果 15次TC比对结果显示,本血脂参考实验室(以下简称"本室")平均CV为0.43%,CDC各参加实验室间CV为0.42%,本室与实验室间总体均值的偏移为0.22%,与CDC靶值的偏移为0.58%。15次TG比对结果显示,本室平均CV为0.62%,本室测定TG的结果与实验室间均值的偏移为-0.98%,与CDC靶值的偏移为-0.80%。TC和TG各60个比对结果中,98%(59/60)的TC测定CV满足CDC的精密度要求,70%(42/60)的测定满足TC准确度要求(TC:CV≤1%,偏移≤1%);92%(55/60)的TG测定准确度满足CDC的要求(TG:偏移≤2.55%)。结论 ID-LC/MS/MS测定血清TC和TG的方法在CRMLN比对中数据良好,与CDC及各网络实验室测定结果一致,有望在我国血脂标准化中发挥重要作用并为参考测量比对计划提供经验和技术支持。     

同位素稀释液相色谱串联质谱法测定血清可替宁

目的 建立一种同位素稀释液相色谱串联质谱(ID-LC/MS/MS)测定血清可替宁的方法,以评价不同吸烟状况健康人的吸烟暴露水平分布状况.方法 以[D3]-可替宁作内标,乙腈沉淀蛋白、离心后吸取上清液、氮气挥干、流动相重组,液相分离后进人串联质谱分析;然后,采用多离子反应监测模式,以标准品制作标准曲线,结合同位素内标法定量建立同位素稀释液相色谱串联质谱法.用以对0 68、48.42、94.34、250.95、287.04 μg/L 5个水平血清样本进行5次重复分析,每次每种血清重复分析3份,以考察方法的精密度;同时测定与评价血清样本添加不同浓度标准品的加样回收率和样本在常温、4℃、-80℃保存的稳定性,以及2010年10月至12月期间94名健康志愿者在不同吸烟状况下的血清可替宁分布情况.并用Mann-Whitney U检验分析60名非吸烟、14名戒烟与20名吸烟健康志愿者血清可替宁含量的差异.结果 用ID-LC/MS/MS检测血清可替宁在本试验条件下分离良好,无内源性物质的干扰,具有较好的特异性;血清可替宁、内标峰面积比与可替宁浓度的线性相关系数≥0.9993;测定5个水平血清样本的总变异系数(CV)分别为4.71％、1.40％、1.98％、1.10％和1.03％;批内CV分别为2.19％、0.78％、0.75％、0.65％和0.67％,ID-LC/MS/MS的检测限(LOD)和定量限(LOQ)分别为0.013和0.050 μg/L,具有较高的灵敏度;3次试验的加样回收率范围为99.22％ ～ 102.67％;样本在常温条件下放置2d、4 ℃放置7d以及-80℃冻存保存3个月测定结果的准确度为99.28％～ 100.87％,批间CV均＜5％.检测94名健康人血清可替宁水平呈偏态和尖态分布(偏度2.71,峰度6.65),其中,20名吸烟者的可替宁浓度为116.40 (63.17 ～241.12) μg/L,14名已成烟者为0.67 (0.15～0.95) μg/L,60名非吸烟者为0.22 (0.15 ～0.42) μg/L;已戒烟者(Z=-2.12,P＜0.05)和吸烟者(Z=-6.67,P＜0.001)血清可替宁浓度分别显著高于非吸烟者.结论 建立的ID-LC/MS/MS测定血清可替宁方法操作简便、特异、灵敏,可望在吸烟暴露水平评价及暴露与疾病发生危险的研究中提供有效技术平台.     

人血清哇巴因UPLC-MS/MS检测方法的建立和方法比对

目的建立超高效液相色谱串联质谱(UPLC-MS/MS)检测人血清哇巴因的方法。方法采用高特异性的UPLC-MS/MS,以氘标记的哇巴因-d3作为内标。样本采用固相萃取(SPE)前处理方法,以反相色谱柱负离子模式及电喷雾电离源(ESI)检测血清哇巴因水平。对建立的方法进行方法学(基质效应、回收率、准确度、批内精密度、批间精密度及稳定性)验证。采用建立的UPLC-MS/MS方法检测20名体检健康者及40例高血压患者血清哇巴因水平,并与酶联免疫吸附试验(ELISA)进行比较。结果 UPLC-MS/MS检测血清哇巴因的标准曲线范围为0.02～5.0 ng/mL,最低定量检测限(LLOQ)为0.02ng/mL。采用ABN固相萃取小柱进行样本前处理的基质效应较小,且回收率较高,达85%。LLOQ和低值(0.06 ng/mL)、中值(0.6 ng/mL)、高值(4 ng/mL)质控品的准确度分别为108.0%、89.2%、101.0%、103.0%。3个水平质控品的批内变异系数(CV)分别为2.87%、1.95%、0.56%,批间CV分别为5.98%、1.90%、0.75%。样本室温过夜放置16 h及样本前处理后室温放置自动进样器48 h的偏差均15%。采用UPLC-MS/MS检测哇巴因,正常对照者及高血压患者血清中均未检测到哇巴因。采用ELISA测定血清哇巴因,高血压患者为0.096 ng/mL,正常对照者为0.062 ng/mL。UPLC-MS/MS检测5个水平(0.02、0.05、0.10、0.20、0.50 ng/mL)的哇巴因标准品,其测定结果与对应的哇巴因标准品浓度呈正相关,且线性较好(r20.99),准确度较高;而ELISA检测5个水平哇巴因标准品的结果均很接近(0.024 9～0.029 6 ng/mL)。结论建立了检测人血清哇巴因的UPLC-MS/MS方法,未检测到正常人及高血压患者的血清哇巴因。UPLC-MS/MS与ELISA检测血清哇巴因的结果存在较大差异。     

酶联免疫吸附法与同位素稀释液相色谱串联质谱法测定GA的一致性研究

目的 分析酶联免疫吸附试验(ELISA)与同位素稀释液相色谱串联质谱法(ID-LC/MS/MS)测定糖化清蛋白(G A)的一致性.方法 收集2020年1-6月该院检验科保留的体检人群剩余血清300份作为研究标本,分别采用ELISA和ID-LC/MS/MS测定血清GA水平.Passing-Bablok回归计算两种方法斜率...     

Pilot study for the standardization of insulin immunoassays with isotope dilution liquid chromatography/tandem mass spectrometry

BACKGROUND: An international working group convened by the American Diabetes Association (ADA) called for a reference measurement procedure for use in a trueness-based standardization project of insulin immunoassays. In view of this demand, we conducted a pilot study to investigate the feasibility of such a standardization project with our isotope dilution-liquid chromatography/tandem mass spectrometry (ID-LC/tandem MS) procedure. METHODS: We evaluated the precision, accuracy, and limit of quantification (LoQ) of the ID-LC/tandem MS procedure by use of insulin-free serum supplemented with insulin to give 3 pools with concentrations of 0.0796, 0.769, and 5.56 microg/L. We conducted a pilot method comparison study with 4 immunoassays and 80 samples from fasting and glucose-stimulated patients. RESULTS: The within-run and total imprecision (CV) ranged from 3.2% to 6.3% and from 4.9% to 12.1% (listing sequence from the high to the low pool). The recovery from supplemented insulin-free sera ranged from 101.8% to 104.1%, and the LoQ was 0.07 microg/L (12 pmol/L). Weighted Deming regression and correlation analysis of the method-comparison data showed considerable between-assay variation for the immunoassays but, with the exception of one assay, excellent correlation with ID-LC/tandem MS. Recalibration of the immunoassay results considerably reduced the between-assay variation. Moreover, after recalibration, 3 of the 4 assays fulfilled the total error specification of 32% proposed by the ADA Workgroup. CONCLUSIONS: Recalibration of insulin assays by regression equations established from method comparison with ID-LC/tandem MS can result in successful standardization and fulfillment of the total error criterion proposed by the ADA Workgroup.     

A candidate reference method for the determination of uric acid in serum based on high performance liquid chromatography, compared with an isotope dilution-gas chromatography-mass spectrometer method

A method based on isocratic high performance liquid chromatography (HPLC) with UV detection at 292 nm is proposed as a candidate reference method for the determination of uric acid. Data obtained by this method are compared with those from an isotope dilution-gas chromatography-mass spectrometric method (ID-GC-MS), using [1,3-15N2]uric acid as internal standard and selected mass detection at m/z = 456 and m/z = 458. The inaccuracy of the ID-GC-MS method is maximally 0.4% for NBS-SRM-909 control sera with a concentration of 483 mumol/l. The coefficient of variation between days is 0.26%-0.80% and 0.37-0.90% for 14 control sera from other suppliers. The maximum bias of the HPLC method is 0.6%, and the coefficient of variation between days is 0.31%-0.65% for NBS-SRM-909 control sera. The coefficient of variation between days for the other 14 control sera tested is 0.35%-0.66%. Comparison of the HPLC method with the reference ID-GC-MS method resulted in a coefficient of correlation of r = 0.9998 (n = 14). The concentration of uric acid in the tested control sera ranged from 160 to 624 mumol/l.     

Precision of glucose measurements in control sera by isotope dilution/mass spectrometry: proposed definitive method compared with a reference method

This improved isotope-dilution gas chromatographic/mass spectrometric (GC/MS) method, in which [13C]glucose is the internal standard, meets the requirements of a Definitive Method. In a first study with five reconstituted lyophilized sera, a nested analysis of variance of GC/MS values indicated considerable among-vial variation. The CV for 32 measurements per serum ranged from 0.5 to 0.9%. However, concentration and uncertainty values (mmol/L per gram of serum) assigned to one serum by the NBS Definitive Method (7.56 +/- 0.28) were practically identical to those obtained with the proposed method (7.57 +/- 0.20). In the second study, we used twice more [13C]glucose diluent to assay four serum pools and two lyophilized sera. The CV ranged from 0.26 to 0.5% for the serum pools and from 0.28 to 0.59% for the lyophilized sera. In comparison, results by the hexokinase/glucose-6-phosphate dehydrogenase reference method agreed within acceptable limits with those by the Definitive Method but tended to be slightly higher (up to 3%) for lyophilized serum samples or slightly lower (up to 2.5%) for serum pools.     

Feasibility of standardization of serum C-peptide immunoassays with isotope-dilution liquid chromatography-tandem mass spectrometry

BACKGROUND: Serum C-peptide concentrations reflect pancreatic function in different clinical and diagnostic settings; however, the utility of C-peptide testing is limited by the lack of standardized commercial immunoassays. Standardization can best be done by split-sample comparison with a hierarchically higher reference measurement procedure with a set of native sera. For serum peptides, isotope-dilution liquid chromatography-mass spectrometry (ID-LC/MS) is recommended as a reference measurement procedure. METHODS: We evaluated the analytical performance characteristics of an ID-LC/tandem MS procedure for measurement of serum C-peptide after a 2-step solid-phase extraction. To investigate the feasibility of this procedure for use in standardization, we also performed a method comparison with 3 representative commercial assays. RESULTS: The ID-LC/tandem MS procedure showed maximum within-run, between-run, and total CVs on dedicated sera (C-peptide concentrations, 1.6 and 4.0 mug/L) of 2.1%, 2.5%, and 2.9%, respectively; an accuracy of 94.6%-104.1%; a minimum trueness of 98.1% (95% confidence interval, 96.2%-100.0%), and limits of quantification and detection of 0.15 and 0.03 mug/L, respectively. Deming linear regression analysis of the method-comparison data showed that the immunoassays correlated well with ID-MS and were specific, but lacked intercomparability and trueness. We propose that the deficiencies can be resolved by recalibration on the basis of the method comparison. CONCLUSIONS: The ID-LC/tandem MS procedure is suitable for specific and accurate measurement of basal and stimulated serum concentrations of proinsulin C-peptide fragment 33-63 and is suitable for use in standardization of C-peptide immunoassays.     

血清尿酸紫外分光光度参考方法的建立及性能评价

目的以尿酸酶紫外光度法为基础,建立血清中尿酸测定的参考方法并评价其性能.方法 用新鲜患者血清样本、迈瑞常规复合校准品等对方法的精密度进行评估;用有证参考物质SRM909bⅠ和Ⅱ、IFCC参考实验室质评样本Rela A/B对方法的准确度进行初步评价,同时测定新鲜人血清并与同位素稀释质谱法进行方法学对比,验证方法准确度.结果 方法对新鲜患者血清、厂家复合校准品等不同类型样本批内不精密度CVintra小于1%,总不精密度CVt小于2%;有证参考物质SRM909bⅠ/Ⅱ测定结果均在参考值范围内,对UA参考实验室能力验证样本Rela A/B测定结果与中心值结果相对偏差小于0.5%;血清样本测定结果与同位素稀释液相质谱法可比,线性回归斜率1.005,相关系数0.999,医学决定水平处引入的相对误差小于3.25%.结论 血清尿酸紫外分光光度法已基本建立,精密度和准确度符合要求,测量结果和同位素稀释液相色谱/质谱法可比,可为常规系统尿酸溯源体系的建立和性能评估提供便捷有效的方法.     

Proposal of a candidate international conventional reference measurement procedure for free thyroxine in serum.

In the present paper the IFCC WG-STFT recommends and provides the rationale to establish metrological traceability of serum free thyroxine (FT4) measurements to a candidate international conventional reference measurement procedure. It is proposed that this procedure be based on equilibrium dialysis combined with determination of thyroxine in the dialysate with a trueness-based reference measurement procedure. The measurand is thus operationally defined as "thyroxine in the dialysate from equilibrium dialysis of serum prepared under defined conditions". With regard to the trueness-based reference measurement procedure, the WG-STFT recommends use of an isotope dilution-liquid chromatography/tandem mass spectrometry (ID-LC/tandem MS) procedure for total thyroxine that has been optimized towards measurement at picomolar concentration levels and that is listed in the database of the Joint Committee for Traceability in Laboratory Medicine (JCTLM). For calibration, the purified thyroxine material IRMM-468 (resulting from a project funded by the European Commission and recently submitted to the JCTLM) is proposed. The WG-STFT stresses that according to this recommendation it is a prerequisite to strictly adhere to the defined equilibrium dialysis procedure, whereas it is permissible to introduce variants in the ID-LC/tandem MS procedure.     

血清尿素同位素稀释气相色谱质谱法的建立和研究

目的 建立一种基于同位素稀释/气相色谱/质谱技术(isotope dilution/gas chromatography/mass spectrometry,ID/GC/MS)的血清尿素候选参考方法.方法 以[13C,15N2]尿素为内标,用无水乙醇沉淀、去除血清中的蛋白类物质,依次使用丙二醛-二甲基缩醛和N-甲基-(三甲基硅烷基)-三氟乙酰胺(MSTFA)将尿素衍生成为三甲基硅烷氧基嘧啶,用气相色谱/质谱(GC/MS)分析衍生产物,以包括法定量.结果 血清尿素测定的批内、批间和总变异系数的平均值分别为0.38%(范围0.12%～0.47%)、0.62%(范围0.49%～0.87%)和0.73%(范围0.51%～0.93%),回收率范围为99.37%～100.95%,分析美国国家标准和技术研究院(NIST)2个水平的血清标准物质SRM 909b,测定结果与靶值的偏差小于0.2%.结论 建立了ID/GC/MS技术测定血清尿素的方法,方法准确、精密、简便,可望作为血清尿素测定的参考方法.