超高效液相色谱-串联质谱法检测猪肉和猪肾中残留的10种镇静剂类药物

建立了猪肉和猪肾中安眠酮、氯丙嗪、异丙嗪、地西泮、硝西泮、奥沙西泮、替马西泮、咪达唑仑、三唑仑和唑吡旦10种镇静剂类药物残留检测的超高效液相色谱-串联质谱分析方法。样品经酶解后,调节pH值呈碱性,分别用乙酸乙酯和叔丁基甲醚进行萃取,高速冷冻离心去除脂肪等杂质。提取液经Waters Acquity UPLC BEH C18色谱柱分离,以0.1%甲酸乙腈溶液和0.1%甲酸水溶液为流动相进行梯度洗脱。电喷雾正离子(ESI+)模式电离,多反应监测(MRM)模式检测,基质匹配标准溶液法进行定量。结果表明: 10种镇静剂在2～100 μg/L范围内呈良好的线性关系,相关系数(r)均大于0.998; 10种镇静剂的检出限(S/N＞3)为0.5 μg/kg,定量限(S/N＞10)为1 μg/kg。3个添加水平的回收率为64.5%～111.4%,批内、批间相对标准偏差(RSD)均小于15%。该方法具有简便快捷、灵敏度高、定性准确等特点。     

分子印迹固相萃取-超高效液相色谱-串联质谱法快速测定猪尿中15种β_2-受体激动剂残留

建立了分子印迹固相萃取(MISPE)-超高效液相色谱-串联质谱(UPLC-MS/MS)快速测定猪尿中15种β_2-受体激动剂的分析方法。分别优化了上样溶液的pH值、淋洗和洗脱溶液等MISPE净化条件及质谱条件。将猪尿样品离心,经MISPE柱上样,依次用水、乙腈、0.5%(v/v)乙酸乙腈溶液淋洗,10%(v/v)乙酸甲醇溶液洗脱,氮气吹干,0.1%(v/v)甲酸水-乙腈(9∶1,v/v)复溶;采用BEH C_(18)色谱柱分离,以乙腈-0.1%(v/v)甲酸水溶液为流动相,采用梯度洗脱,在电喷雾正离子多反应监测模式下外标法定量。考察了MISPE对15种β_2-受体激动剂的吸附特异性;猪尿中15种β_2-受体激动剂在0.1~20μg/L范围内线性关系良好(r~2≥0.992);检出限和定量限分别为0.03和0.1μg/L;15种β_2-受体激动剂的加标回收率为65.6%~115.0%,批内、批间相对标准偏差分别为0.57%~16.1%和1.11%~16.8%。该方法操作简单、快速、灵敏度高、特异性好。     

高效液相色谱法测定猪尿中克伦特罗对映异构体残留量

建立了测定猪尿中克伦特罗对映异构体残留量的高效液相色谱分析方法.在碱化的条件下,用乙酸乙酯提取10 mL猪尿样品,提取液经稀HCl反萃取,萃取液直接过SCX固相萃取小柱,再用5%氨化甲醇洗脱,洗脱液经氮气吹干后用200 μL甲醇定容.采用Astec CHIROBIOTICTM V手性色谱柱,以V(甲醇)∶ V(冰乙酸)∶ V(三乙胺)=99.94∶ 0.02∶ 0.04为流动相进行HPLC分析,检测波长301 nm,外标法定量.克伦特罗单-对映体的峰面积与其浓度在70～5000 μg/L范围内呈良好的线性; 线性相关系数均大于0.9996; 猪尿样品中检出限为0.30 μg/L.猪尿中克伦特罗对映体在1.0～20.0 μg/L范围内的添加回收率为76.3%～91.5%; 相对标准偏差RSD均小于7%(n=5).     

高效液相色谱-串联质谱法测定蜂蜜中残留的19种喹诺酮类药物

建立了高效液相色谱-电喷雾串联质谱联用测定蜂蜜中恩诺沙星、环丙沙星、诺氟沙星、氧氟沙星、双氟沙星、恶喹酸、氟甲喹、沙拉沙星、司帕沙星、丹诺沙星、氟罗沙星、马波沙星、伊诺沙星、奥比沙星、吡哌酸、培氟沙星、洛美沙星、西诺沙星和萘啶酸等19种喹诺酮类药物残留的方法。比较酸性溶液阳离子固相萃取(PCX柱)、近中性缓冲溶液反相固相萃取（HLB柱）和碱性溶液阴离子固相萃取(PAX柱)3种不同提取净化方法的提取效果,最终选择使用碱性溶液溶解蜂蜜样品,强阴离子固相萃取柱一步富集净化。以甲醇和0.1%甲酸溶液作为流动相,C18作为分析色谱柱,采用梯度洗脱方式进行液相色谱分离,选择离子反应监测模式检测19种喹诺酮类药物,内标方法定量。在1～100 μg/L范围内,19种喹诺酮类药物的线性相关系数均大于0.991。通过实际样品的添加回收试验,方法的定量限（S/N=10）为1.0 μg/kg,3个添加水平的回收率为71%～118%,相对标准偏差为4.2%～6.7%。     

蜂产品中9种硝基咪唑类药物原药及代谢物残留量的HPLC-APCI(+)MS/MS分析

运用高效液相色谱-大气压电离串联四极杆质谱(HPLC-APCI(+)MS/MS)内标法分析了蜂蜜、蜂王浆及冻干粉中甲硝唑、地美硝唑(二甲硝唑)、替硝唑、洛硝唑(罗硝唑)、特尼哒唑、异丙硝唑,以及羟基化甲硝咪唑、羟基化异丙硝唑、2-羟甲基-1-甲基化-5-硝咪唑9种硝基咪唑类药物残留量.样品添加氘代标示物HMMNI-D3、IPZ-OH-D3后,用乙腈提取,通过Oasis MCX C18 SPE柱净化,Waters Superiorex ODS C18色谱柱分离,采用梯度洗脱,流动相为0.1%甲酸水溶液和0.1%甲酸乙腈溶液,大气压电离源正离子MRM模式检测.蜂蜜和蜂王浆样品的定量下限(LOQ,S/N＞10)为0.5 μg/kg,冻干粉样品的LOQ为1.0 μg/kg.在0.5 ～50.0 μg/L范围内,峰面积与质量浓度呈良好线性,r为0.993 2 ～0.999 5.     

自动固相萃取-液相色谱-串联质谱法同时测定血液中5种抗抑郁类药物

建立了血液中5种抗抑郁类药物的自动固相萃取-液相色谱-串联质谱(ASPE-LC-MS/MS)分析方法。样品经HLB固相萃取柱提取后,采用LC-MS/MS进行测定,外标法定量。在Waters AtlantisTM dC18反相柱上分离,梯度洗脱,流动相为甲醇-0.1%甲酸(1∶4,V/V)溶液,质谱采集为电喷雾正离子多反应监测模式。采用基质匹配标准溶液校正,5种目标物在1~500μg/L范围内具有良好的线性关系,相关系数(R)大于0.9975,检出限在0.1~0.6μg/L之间;添加浓度水平为10,100和500μg/L时,方法回收率为70.6%~93.8%,相对标准偏差在3.9%~9.2%之间。本方法可用于血液中5种抗抑郁类药物的法庭与临床毒物分析。     

超高效液相色谱-电喷雾串联质谱法同时分析鸡肉中7种氟喹诺酮类药物残留

建立了一种同时测定鸡肉中7种氟喹诺酮类药物残留的超高效液相色谱-电喷雾串联质谱确证分析方法(UPLC-ESI-MS/MS)。样品经酸化乙腈提取、正己烷脱脂和HLB固相萃取柱净化,采用ACQUITY UPLCTM BEH C18色谱柱(50 mm×2.1 mm,1.7 μm)分离,以0.1%甲酸水溶液和乙腈作为流动相进行梯度洗脱,电喷雾质谱检测,正离子多反应监测模式进行定性和定量分析。7种药物在5～100 μg/kg范围内线性关系良好,相关系数(r2)均大于0.99;以5,25,50 μg/kg3个浓度水平进行添加回收试验,7种药物的平均回收率在79.2%～108.6%之间,相对标准偏差为4.2%～8.9%,方法的检出限(LOD)为0.2～1.4 μg/kg。方法重现性好、灵敏度高、分析时间短、确证能力强,适用于鸡肉中氟喹诺酮类药物多残留的确证检测。     

固相萃取-液相色谱-飞行时间质谱法快速筛查与确证谷物和果蔬中25种杀菌剂残留

利用固相萃取-液相色谱-飞行时间质谱(SPE-LC-Q-TOF/MS)技术建立了谷物、 蔬菜和水果中25种杀菌剂农药残留的快速筛查和确证检测方法.样品经1%(V/V)乙酸-乙腈溶液提取,经Crabon/NH2柱净化,乙腈-甲苯(3∶1, V/V)洗脱,C18色谱柱分离,乙腈和0.1% 甲酸溶液(含5 mmol/L乙酸铵)梯度洗脱,采用LC-Q-TOF/MS检测,外标法定量.建立了25种杀菌剂的一级精确质量数据库和二级谱图库,通过化合物的精确质量数、 保留时间、 同位素峰分布、 同位素比例等信息对检测结果进行自动检索,在无对照标准品的情况下实现了25种农药的定性鉴定.结果表明,25种杀菌剂在0.02~200 μg/L范围内线性关系良好,相关系数R2≥0.9950, 加标回收率在71.8%~114.0%之间,相对标准偏差(RSD)为0.1%~21.3% (n=3).25种杀菌剂检出限为0.01~5.00 μg/kg,定量限为0.02~20.00 μg/kg.本方法简便、 快速、 可靠,可用于谷物、 蔬菜、 水果中25种杀菌剂的快速筛查.     

液相色谱-串联质谱法测定蔬菜水果中的吡丙醚残留量

建立了测定蔬菜、水果中吡丙醚残留量的液相色谱-串联质谱(LC-MS/MS)分析方法。样品在醋酸钠缓冲液下用酸性乙腈提取,取1 mL提取液用PSA（N-丙基乙二胺）填料净化后,采用CAPCELL PAK C18色谱柱(50 mm×2.0 mm,3 μm)分离,以含0.1%甲酸的乙腈溶液和含0.1%甲酸的2 mmol/L乙酸铵溶液作为流动相进行梯度洗脱,以电喷雾电离三重四极杆串联质谱在正离子多反应监测(MRM)模式下进行测定。吡丙醚在2.5～50 μg/L范围内呈线性关系,相关系数为0.9999,在5,50,100 μg/kg 3个添加水平下的回收率为84.7%～91.5%,相对标准偏差(RSD,n10)低于10%。该方法操作简便,稳定性和选择性好,灵敏度高(检出限为5 μg/kg),适用于蔬菜、水果中吡丙醚残留量的测定。     

超高效液相色谱-串联质谱法对动物源性食品中13种β-内酰胺类药物残留的检测

建立了动物源性食品中青霉素G、青霉素V、阿莫西林、羧苄西林、氨苄西林、苯唑西林、氯唑西林、萘夫西林、头孢喹肟、头孢氨苄、头孢拉定、头孢唑啉和头孢哌酮13种β-内酰胺类药物残留检测的超高效液相色谱-串联质谱(UPLC-MS/MS)分析方法.样品经水和乙腈提取后,用正己烷去除脂肪,再用C18固相萃取柱净化,浓缩后用BEH C18色谱柱(50 mm×2.1 mm,1.7 μm)分离 ,以0.1%甲酸乙腈溶液和0.1%甲酸水溶液为流动相进行梯度洗脱,电喷雾正离子(ESI+)模式电离,多反应监测(MRM)模式检测.结果表明:在5 ～500 μg/L的基质匹配标准溶液内13种β-内酰胺类药物均有良好的线性关系,相关系数(r)均大于0.998;样品中13种β-内酰胺类药物的检出限(LOD)均为1 ng/g,定量下限(LOQ)均为2 ng/g;在5 ～50 ng/g的加标范围内13种β-内酰胺类药物的平均回收率为79% ～99%,相对标准偏差(RSD)小于13.5%.     

Preparation, characterization, and chemical stability of gold nanoparticles coated with mono-, bis-, and tris-chelating alkanethiols

A systematically varying series of monolayer-protected clusters (MPCs) was prepared by exposing small gold nanoparticles ( approximately 2 nm in diameter) to the following four adsorbates: n-octadecanethiol ( n - C18), 2-hexadecylpropane-1,3-dithiol ( C18C2), 2-hexadecyl-2-methylpropane-1,3-dithiol ( C18C3), and 1,1,1-tris(mercaptomethyl)heptadecane ( t - C18). The resultant MPCs were characterized by solubility studies, UV-vis spectroscopy, transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and Fourier-transform infrared spectroscopy (FT-IR). All of the MPCs were soluble in common organic solvents; moreover, analysis by TEM showed that the core dimensions were unaffected by exposure to any of the adsorbates. Separate studies by XPS revealed that the sulfur atoms in all MPCs were predominantly bound to the surface of gold (i.e., approximately 85% or better). Analysis by FT-IR showed that MPCs functionalized with n - C18 possessed alkyl chains having the greatest conformational order in both the solid-state and dispersed in solution; in contrast, those generated from the other three adsorbates were more liquid-like with reduced conformational order (or crystallinity). The rate of nanoparticle decomposition induced by cyanide ions was monitored by UV-vis spectroscopy. While MPCs functionalized with n - C18 showed the fastest rate of decomposition, those functionalized with C18C3 were the most resistant to decomposition. Overall, the following trend in chemical stability was observed, C18C3 > C18C2 > t - C18 > n - C18.     

A method for calculating <Superscript>16</Superscript>o/<Superscript>18</Superscript>o peptide ion ratios for the relative quantification of proteomes

A method is described for the identification and relative quantification of proteomes using accurate mass tags (AMT) generated by nLC-dual ESI-FT-ICR-MS on a 7T instrument in conjunction with stable isotope labeling using 16O/18O ratios. AMTs were used for putative peptide identification, followed by confirmation of peptide identity by tandem mass spectrometry. For a combined set of 58 tryptic peptides from bovine serum albumin (BSA) and human transferrin, a mean mass measurement accuracy of 1.9 ppm +/-0.94 ppm (CIM99%) was obtained. This subset of tryptic peptides was used to measure 16O/18O ratios of 0.36 +/- 0.09 (CIM99%) for BSA (micro = 0.33) and 1.48 +/- 0.47 (CIM99%) for transferrin (micro = 1.0) using a method for calculating 16O/18O ratios from overlapping isotopic multiplets arising from mixtures of 16O, 18O1, and 18O2 labeled C-termini. The model amino acid averagine was used to calculate a representative molecular formula for estimating and subtracting the contributions of naturally occurring isotopes solely as a function of peptide molecular weight. The method was tested against simulated composite 16O/18O spectra where peptide molecular weight, 16O/18O ratio, 18O1/18O2 ratios, and number of sulfur atoms were varied. Relative errors of 20% or less were incurred when the 16O/18O ratios were less than three, even for peptides where the number of sulfur atoms was over- or under-estimated. These data demonstrate that for biomarker discovery, it is advantageous to label the proteome representing the disease state with 18O; and the method is not sensitive to variations in 18O1/18O2 ratio. This approach allows a comprehensive differentiation of expression levels and tentative identification via AMTs, followed by targeted analysis of over- and under-expressed peptides using tandem mass spectrometry, for applications such as the discovery of disease biomarkers.     

Synthesis of Codon-optimized Human Interleukin-18 Gene by Combination of Chemical and Enzymatic Method

According to the amino acid sequence and codon preference of E. coli, the human interleukin-18（IL-18） gene was optimized to avoid the rare codons. The total length of the synthesized gene is 571 bp; 18 oligonucleotides, DNA fragments were designed and synthesized by the phosphoramidite four-step chemical method. The whole DNA sequence was synthesized by a one-step total gene synthesis method, and then inserted in pUC18 vector. Five positive clones identified by blue-white colony screening were sent to Shanghai Sangon Biological Engineering Technology and Service Co., Ltd. for sequencing. The sequencing result shows that one clone contained the complete correct gene in all the five positive clones.     

Quantitative Determination of Isostearic Acid Isomers in Skin Creams by GC-MS-SIM

“Isostearic acid” is frequently listed as an ingredient of skin creams and other cosmetics. In the four skin creams analyzed, “isostearic acid” was esterified with isopropanol, as well as sorbitan or polyglycerols. “Isopropyl isostearate” was isolated by HCl treatment and saponification whereas emulsifiers (sorbitan or polyglycerol isostearates) were enriched by means of a C₁₈-cartridge. Fatty acids in the resulting lipid fraction were transferred into methyl esters. 25:0 and 19:0 methyl esters were used as internal standards. GC-EI-MS was used to determine that “isostearic acid” was a mixture of many methyl-branched isomers of stearic acid (18:0) in all four skin creams. Thus, it may be better termed “isostearic acids”. The branched-chain nature of isostearates was verified by formation and analysis of picolinyl esters of skin cream fatty acids by GC-EI-MS. Twenty-five 18:0 isomers were detected and the main products had one methyl branch on carbons C₁₀–C₁₄. Two late eluting isostearic acid isomers were identified as 16-methyl heptadecanoic acid (i18:0) and 15-methyl heptadecanoic acid (a18:0). GC-EI-MS in the selected ion monitoring (SIM) mode with m/z 87 as quantification ion was used for the determination of i18:0 methyl ester. The quantities of i18:0 in the samples amounted to 10–20 mg g^?1 skin cream. The contribution of i18:0 to the sum of all 18:0 isomers in the four skin cream samples was 8.5 ± 1.1%. Instead of determining all individual isostearates in a product, we suggest the quantitative determination of i18:0 followed by multiplication with factor 11.75 (~reciprocal value of 8.5%, see above) as a simple method for the quantification of isostearates in cosmetics.     

Reversed-phase high-performance liquid chromatographic separation of tert.-butyl hydroperoxide oxidation products of unsaturated triacylglycerols

Triacylglycerols containing monounsaturated fatty acids are known to be relatively resistant to autoxidation and require long periods of exposure to dilute oxidants. Use of concentrated solutions of synthetic hydroperoxides, however, yields in addition to the hydroperoxides also unidentified oxidation by-products. In the present study we have employed synthetic triacylglycerols containing one (18:0/18:1/18:0 and 18:1/16:0/16:0) and two (18:0/18:0/18:2 and 18:1/18:1/18:0) double bonds per molecule to reinvestigate the formation of oxotriacylglycerols using tert.-butyl hydroperoxide as an oxidant. Reversed-phase HPLC was used to separate and tentatively identify the oxidation products based on relative retention times of standards and the estimated elution factors for functional groups and their positional distribution. Hydroperoxides, diepoxides and hydroxides were the major components of the oxidation mixtures (50-95% of total). Previously unidentified peroxide-bridged tert.-butyl adducts were present in significant amounts (5-50% of total oxidation products) in all preparations. In several instances more than one functional group was present on a single fatty chain. The tentative reversed-phase chromatographic identification of the adducts was confirmed by determination of the molecular mass of each component by on-line LC with electrospray MS. The oxidation products were quantified by HPLC with light scattering detection.     

Separation of enantiomers by capillary electrophoresis-mass spectrometry employing a partial filling technique with a chiral crown ether

Enantiomer separations were performed by capillary electrophoresis-mass spectrometry (CE-MS) with (+)-(18-crown-6)-2,3,11,12-tetracarboxylic acid (18C6H4) as a chiral selector. In order to prevent the introduction of the nonvolatile chiral, selector, 18C6H4, into the nozzle of the CE-MS interface and/or the orifice plate, a partial filling technique was employed in this study. By the partial filling technique, the contamination caused by the nonvolatile chiral selector was avoided not only during the analysis but also during the washing of capillary with the separation solution prior to the run. Several racemic compounds having a primary amino group were successfully separated. Racemic 3-aminopyrrolidine and racemic alpha-amino-epsilon-caprolactam have no strong UV absorption, but such compounds were detected with a high sensitivity by MS detection. In this paper, the effects of the length of separation zone and those of the 18C6H4 concentration were described. As the length of the separation zone was longer or as the concentration of 18C6H4 was higher, the enantiomer resolution was enhanced more and more. However, the optimization of 18C6H4 concentration was practically enough to obtain the baseline separation.     

Application of crown ethers as modifiers for the separation of amines by capillary electrophoresis

The separation of amines with capillary electrophoresis (CE) was made possible by applying crown ethers such as 18-crown-6 and 15-crown-5 as modifiers. Crown ether 18-crown-6 performed better as a modifier than 15-crown-5. The mobility change of primary amines with 18-crown-6 was larger than that for secondary and tertiary amines. The mobility change of various amines with 18-crown-6 were in the order: 1-aminobutane>2-aminobutane>2-amino-2-methylpropane. Effects of crown ether concentration, pH and cations in the eluent of CE were also investigated and discussed. Some neurotransmitters such as dopamine, serotonin, epinephrine, isoproterenol and phenylalanine were separated successfully by using crown ethers in CE analysis.     

Development of an on-column enrichment technique based on C18-functionalized magnetic silica nanoparticles for the determination of lidocaine in rat plasma by high performance liquid chromatography

In this study, a novel on-column enrichment technique filled with C(18)-functionalized magnetic silica nanoparticles was successfully developed for the determination of lidocaine in rat plasma by high performance liquid chromatography (HPLC). The synthesized Fe(3)O(4)@SiO(2)-C(18) nanoparticles were locally packed into the capillary by the application of magnets. Lidocaine in the sample solutions pumped into the capillary tube could be easily adsorbed by Fe(3)O(4)@SiO(2)-C(18) through hydrophobic interaction by the interior C(18) groups, and eluted by acetonitrile solution. Different extraction conditions were investigated. Method validations including linear range, quantification limit, detection limit, precision, accuracy and recovery were also studied. The results showed that the proposed method based on on-column enrichment by Fe(3)O(4)@SiO(2)-C(18) was a novel, little solvent and efficient approach for the determination of lidocaine in the complex plasma samples.     

叶绿素-a及其衍生物的Qy轴向氧化反应和E-环重排反应

在酸碱性条件下对叶绿素-a (1)进行空气氧化反应, 分别得到卟吩衍生物2b～4b; 通过酯交换和去金属镁离子, 将叶绿素-a转化为脱镁叶绿酸-a甲酯(MPa) (5), 其3-位碳碳双键与氯化氢的加成生成卟吩醇(6), 经碱性空气氧化和E-环重排则转化成紫红素-18衍生物7. 选用四氧化锇和高碘酸钠将5氧化成卟吩醛(8), 在丁醇中以丁醇钠作催化剂, 8的氧化和重排反应给出3-甲酰基紫红素-18酯(9)和紫红素-7三甲酯衍生物10. 异构体4的空气氧化和重排反应也生成紫红素-18酯(3), 进一步与2-甲基丁胺进行缩合反应, 得到N-烷基紫红素-18酰亚胺(11a)以及氧化重排产物3-甲酰基-N-烷基紫红素-18酰亚胺(11b). 所得叶绿素衍生物均经UV, IR, 1H NMR及元素分析证明其结构, 并对相应的反应提出可能的反应机理.     

Quantitative determination of phosphatidylcholine hydroperoxides during copper oxidation of LDL and HDL by liquid chromatography/mass spectrometry

1-Palmitoyl-2-linoleoylphosphatidylcholine monohydroperoxide (PC 16:0/18:2-OOH) and 1-stearoyl-2-linoleoylphosphatidylcholine monohydroperoxide (PC 18:0/18:2-OOH) were measured by liquid chromatography/mass spectrometry (LC/MS) using nonendogenous 1-palmitoyl-2-heptadecenoylphosphatidylcholine monohydroperoxide as an internal standard. The calibration curves for synthetic PC 16:0/18:2-OOH and PC 18:0/18:2-OOH, which were obtained by direct injection of the internal standard into the LC/MS system, were linear throughout the calibration range (0.8-12.8 pmol). Within-day and between-day coefficients of variation were less than 10%, and the recoveries were between 86% and 105%. The limit of detection (LOD) and the limit of quantification (LOQ) were determined using synthetic standards. The LOD (signal-to-noise ratio 3:1) was 0.01 pmol, and the LOQ (signal-to-noise ratio 6:1) was 0.08 pmol for both PC 16:0/18:2-OOH and PC 18:0/18:2-OOH. With use of this method, the concentrations of PC 16:0/18:2-OOH and PC 18:0/18:2-OOH in the lipoprotein fractions during copper-mediated oxidation were determined. We prepared oxLDL and oxHDL by incubating native LDL and native HDL from human plasma (n = 10) with CuSO(4) for up to 4 h. The time course of the PC 16:0/18:2-OOH and PC 18:0/18:2-OOH levels during oxidation consisted of three phases. For oxidized LDL, both compounds exhibited a slow lag phase and a subsequent rapidly increasing propagation phase, followed by a gradually decreasing degradation phase. In contrast, for oxidized HDL, both compounds initially exhibited a prompt propagation phase with a subsequent plateau phase, followed by a rapid degradation phase. The analytical LC/MS method for phosphatidylcholine hydroperoxides might be useful for the analysis of biological samples.