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High-performance Liquid Chromatography/electrospray Ionization Tandem Mass Spectrometry (high-performance + liquid_chromatography_ionization_tandem_mass_spectrometry)
Selected AbstractsHigh-performance liquid chromatography/electrospray ionization tandem mass spectrometry of hydroxylated uroporphyrin and urochlorin derivatives formed by photochemical oxidation of uroporphyrinogen IBIOMEDICAL CHROMATOGRAPHY, Issue 5 2007Malcolm Danton Abstract Hydroxylated uroporphyrin I and urochlorin I derivatives formed by photochemical oxidation of uroporphyrinogen I were separated by high-performance liquid chromatography and fully characterized by electrospray ionization tandem mass spectrometry. The porphyrins and chlorins were identified by analysis of their product ion spectra with each hydroxylated derivative giving a characteristic collision-induced dissociation fragmentation pattern. The porphyrins and chlorins characterized were meso -hydroxyuroporphyrin I, , -hydroxypropionic acid uroporphyrin I, , -hydroxypropionic acid uroporphyrin I, hydroxyacetic acid uroporphyrin I, trans- 7-hydroxy-8-spirolactoneurochlorin I, cis- 7-hydroxy-8-spirolactoneurochlorin I and trans- and cis- 7,8-dihydroxyurochlorins I. Copyright © 2007 John Wiley & Sons, Ltd. [source] Rapid screening assay of congenital adrenal hyperplasia by measuring 17,-hydroxyprogesterone with high-performance liquid chromatography/electrospray ionization tandem mass spectrometry from dried blood spotsJOURNAL OF CLINICAL LABORATORY ANALYSIS, Issue 1 2002Chien-Chen Lai Abstract A rapid, simple, and specific method was developed for the diagnosis of congenital adrenal hyperplasia (CAH) from dried blood spots on newborn screening cards based on high-performance liquid chromatography/electrospray ionization tandem mass spectrometry (HPLC/ESI-MS/MS). The usefulness of 17,-hydroxyprogesterone (17OH-P) determination on dried filter-paper blood samples from patients with CAH caused by 21-hydroxylase deficiency was evaluated. The LC/MS/MS detection of 17OH-P was rapid, <4 min. The intra- and interday accuracy and precision of the method were <7%. Our procedure maintained good linearities (R2 > 0.992) and recovery rate (>83%). We used this new method to directly determine the 17OH-P levels in dried blood specimens from abnormal children of various ages, with a detection limit of 20 ng/ml (,240 pg), to avoid the time-consuming derivatization steps required by the gas-chromatography/mass spectrometry (GC/MS) method. Four dried filter-paper blood samples of CAH patients (three girls and one boy, 1,14 years old) were all quantified in an LC/MS/MS study and revealed high 17OH-P levels (>90 ng/ml). After treatment, all of the elevated 17OH-P levels either decreased or disappeared. Compared with CAH patients, 17OH-P was nearly undetectable (<20 ng/ml) in the normal infants by LC/MS/MS. This LC/MS/MS assay is not only useful for both diagnosis and monitoring of treatment of CAH in all other age groups, it also can be used as a screening test for CAH infants. In this study, we provided the first data on 17OH-P in dried blood specimens affected with CAH using HPLC/ESI-MS/MS. J. Clin. Lab. Anal. 16:20,25, 2002. © 2002 Wiley-Liss, Inc. [source] Analysis of urinary nucleosides as helper tumor markers in hepatocellular carcinoma diagnosisRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 11 2009Long-Bin Jeng Hepatocellular carcinoma (HCC) is a common neoplasm in Taiwan, for which early diagnosis is difficult and the prognosis is usually poor. HCC is usually diagnosed by abdominal sonography and serum alpha-fetoprotein (AFP) detection. Modified nucleosides, regarded as indicators for the whole-body turnover of RNAs, are excreted in abnormal amounts in the urine of patients with malignancies and can serve as tumor markers. We analyzed the excretion patterns of urinary nucleosides from 25 HCC patients and 20 healthy volunteers by high-performance liquid chromatography/electrospray ionization tandem mass spectrometry (HPLC/ESI-MS/MS) under optimized conditions. The HPLC/ESI-MS/MS approach with selective reaction monitoring (SRM) allowed for the sensitive determination of nucleosides in human urine samples. The mean levels of the urinary nucleosides adenosine, cytidine, and inosine were significantly higher in HCC patients than healthy volunteers (average of 1.78-, 2.26-, and 1.47-fold, respectively). However, the mean levels of urinary 1-methyladenosine, 3-methylcytidine, uridine, and 2,-deoxyguanosine were not significantly different. Combined with the determination of serum AFP levels, the higher levels of urinary adenosine, cytidine, and inosine may be additional diagnosis markers for HCC in Taiwanese patients. Copyright © 2009 John Wiley & Sons, Ltd. [source] Characterization of covalent addition products of chlorogenic acid quinone with amino acid derivatives in model systems and apple juice by high-performance liquid chromatography/electrospray ionization tandem mass spectrometryRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 4 2008Susanne Schilling High-performance liquid chromatography (HPLC) coupled to electrospray ionization tandem mass spectrometry (ESI-MSn) was used to study the covalent interactions between chlorogenic acid (CQA) quinone and two amino acid derivatives, tert -butyloxycarbonyl-L-lysine and N -acetyl-L-cysteine. In a model system at pH 7.0, the formation of covalent addition products was demonstrated for both derivatives. The addition product of CQA dimer and tert -butyloxycarbonyl-L-lysine was characterized by LC/MSn as a benzacridine structure. For N -acetyl-L-cysteine, mono- and diaddition products at the thiol group with CQA quinone were found. In apple juice at pH 3.6, covalent interactions of CQA quinone were observed only with N -acetyl-L-cysteine. Taking together these results and those reported by other groups it can be concluded that covalent interactions of amino side chains with phenolic compounds could contribute to the reduction of the allergenic potential of certain food proteins. Copyright © 2008 John Wiley & Sons, Ltd. [source] Identification of heat-induced degradation products from purified betanin, phyllocactin and hylocerenin by high-performance liquid chromatography/electrospray ionization mass spectrometryRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 18 2005Kirsten M. Herbach Betanin, phyllocactin (malonylbetanin) and hylocerenin (3-hydroxy-3-methylglutarylbetanin) were isolated from purple pitaya (Hylocereus polyrhizus [Weber] Britton & Rose) juice, and their degradation products generated by heating at 85°C were subsequently monitored by high-performance liquid chromatography/electrospray ionization tandem mass spectrometry. Thermal degradation of phyllocactin and hylocerenin in purified solution excluding the alleged protective effects by the juice matrix is reported for the first time. Betanin was predominantly degraded by hydrolytic cleavage, while decarboxylation and dehydrogenation were of minor relevance. In contrast, hylocerenin showed a strong tendency to decarboxylation and dehydrogenation, hydrolytic cleavage of the aldimine bond occurring secondarily. Phyllocactin degradation was most complex because of additional decarboxylation of the malonic acid moiety as well as generation and subsequent degradation of betanin due to phyllocactin demalonylation. Upon prolonged heating, all betacyanins under observation formed degradation products characterized by an additional double bond at C2C3. Hydrolytic cleavage of the aldimine bond of phyllocactin and hylocerenin yielded previously unknown acylated cyclo -dopa derivatives traceable by positive ionization, while application of ESI(,) facilitated the detection of a glycosylated aminopropanal derivative and dopamine, which have never been described before as betanin degradation products. Copyright © 2005 John Wiley & Sons, Ltd. [source] Differential adduction of proteins vs. deoxynucleosides by methyl methanesulfonate and 1-methyl-1-nitrosourea in vitro,RAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 4 2005Fagen Zhang The reactions of two model mutagenic and carcinogenic alkylating agents, N -methyl- N -nitrosourea (MNU) and methyl methanesulfonate (MMS), with proteins and deoxynucleosides in vitro, were investigated. The protein work used an approach involving trypsin digestion and high-performance liquid chromatography/electrospray ionization tandem mass spectrometry (HPLC/ESI-MS/MS). This technique permitted identification of the specific location of protein adduction by both MNU and MMS with commercial apomyoglobin and human hemoglobin, under physiological conditions. MNU treatment resulted in predominantly carbamoylation adducts on the proteins, but in contrast only methylated protein adducts were found following treatment with MMS. Further analyses, using TurboSequest®, and the Scoring Algorithm for Spectral Analysis (SALSA), revealed that MNU carbamoylation was specific for modification of either the N-terminal valine or the free amino group in lysine residues of apomyglobin and human hemoglobin. However, MMS methylation modified the N-terminal valine and histidine residues of the proteins. Despite their clear differences in protein modifications, MNU and MMS formed qualitatively the same methylated deoxynucleoside adduct profiles with all four deoxynucleosides in vitro under physiological conditions. In light of their different biological potencies, where MMS is considered a ,super clastogen' while MNU is a ,super mutagen', these differences in reaction products with proteins vs. deoxynucleosides may indicate that these two model alkylating agents work via different mechanisms to produce their mutagenic and carcinogenic effects. Copyright © 2005 John Wiley & Sons, Ltd. [source] Congener-specific analysis of hexabromocyclododecane by high-performance liquid chromatography/electrospray tandem mass spectrometryRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 13 2003Wesley Budakowski A congener-specific method based on high-performance liquid chromatography/electrospray ionization tandem mass spectrometry (HPLC/ES-MS/MS) in the negative ion mode was developed for the analysis of hexabromocyclododecane (HBCDD). On a C18 analytical column, with a methanol/water mobile phase, the , -isomer was completely resolved from the , - and , -isomers while the , - and , -isomers were sufficiently resolved at half their peak heights. The ES spray voltage strongly influenced the intensity of the ion signal. For MS, a source temperature of 500°C and a collision energy of 50,eV were found to be optimum for the [M,H], to Br, transition. Run-to-run and day-to-day (n,=,3) variability was minimal, with relative standard deviations of 2.6,4.1 and 2.4,4.4%, respectively. The limit of detection was 4,6,pg on-column. When applied to tissue samples from Lake Winnipeg fish both , - and , -isomers of HBCDD were found in low-ng/g (lipid corrected) concentrations. Copyright © 2003 John Wiley & Sons, Ltd. [source] Synthesis of benzofurazan derivatization reagents for carboxylic acids in liquid chromatography/electrospray ionization,tandem mass spectrometryBIOMEDICAL CHROMATOGRAPHY, Issue 11 2007Tomofumi Santa Abstract The applicability of benzofurazan derivatization regents to carboxylic acids analysis in LC/ESI-MS/MS (high-performance liquid chromatography/electrospray ionization tandem mass spectrometry) was examined. The product ion spectra of DAABD-AE {4-[2-(N,N -dimethylamino)ethylaminosulfonyl]-7-(2-aminoethylamino)-2,1,3-benzoxadiazole}, DAABD-PZ {4-[2-(N,N -dimethylamino)ethylaminosulfonyl]-7- N -piperazino-2,1,3-benzoxadiazole}, DAABD-PiCZ {4-[4-carbazoylpiperidin-1-yl]-7-[2-(N,N -dimethylamino)ethylaminosulfonyl]-2,1,3-benzoxadiazole}, DAABD-ProCZ {4-[2-carbazoylpyrrolidin-1-yl]-7-[2-(N,N -dimethylamino) ethylaminosulfonyl]-2,1,3-benzoxadiazole} and DAABD-Apy {4-[2-(N,N -dimethylamino)ethylaminosulfonyl]-7-(3-aminopyrrolidin-1-yl)-2,1,3-benzoxadiazole}, and their acetylated compounds were obtained. An intense fragment ion at m/z 151 corresponding to (dimethylamino)ethylaminosulfonyl moiety was observed in each spectra, suggesting that these reagents were suitable for ESI-MS/MS analysis. DAABD-AE, DAABD-APy and DAABD-PZ were applied to the analysis of octanoic acid and it was found that DAABD-AE and DAABD-APy gave high signal intensity suitable for LC/ESI-MS/MS. Copyright © 2007 John Wiley & Sons, Ltd. [source] | ||||||||||