Monolithic silica spin column extraction （MonoSpin-SPE） was developed as a simple, sensitive, and eco-friendly pretreatment method which combined with ultra-fast liquid chromatography-mass spectrometry （UFLC-MS） t...Monolithic silica spin column extraction （MonoSpin-SPE） was developed as a simple, sensitive, and eco-friendly pretreatment method which combined with ultra-fast liquid chromatography-mass spectrometry （UFLC-MS） to determine the levels of six phthalate esters, dimethyl- （DMP）, diethyl- （DEP）, dipropyl- [ DPrP], butyl-benzyl- （BBP）, dicyclohexyl- （DcHP）, and di-n-octyl-（DOP） phthalate in physiological saline samples. Under optimized experimental conditions, the method was linear in the following ranges： 0.2- 50 μg/L for DMP, DEP, DPrP, DcHP and DOP; 5- 100 μg/L for BBP. The correlation coefficients （R2 ） were in the range of 0. 9951 - 0. 9995 for all the analytes and the limits of detection （LODs） and limits of quantification （LOQs） were in the ranges of 0.02 - 0.9 μg/L and 0.08 - 2.7μg/L, respectively. The pretreatment process showed good reproducibility with inter-day and intra-day relative standard deviations （RSDs） below 8.5% and 11.2%, respectively. This method was used to determine the levels of six phthalate esters in physiological saline samples and the recoveries ranged from 71.2% to 107.3%. DMP and DEP were found in actual physical saline samples （brand A and brand B）.展开更多
hloramphenicol is an antibiotic and one of the potential contaminants in honey.Solid-phase extraction is the key pretreatment procedure for analysis of chloramphenicol in honey.In this work,an on-line pretreatment liq...hloramphenicol is an antibiotic and one of the potential contaminants in honey.Solid-phase extraction is the key pretreatment procedure for analysis of chloramphenicol in honey.In this work,an on-line pretreatment liquid chromatography-tandem mass spectrometer system for sensitive,reliable and higher throughput analysis was developed.With the methylcellulose-immobilized reversed-phase column,sugars in a honey sample were efficiently removed in 1 min.As a result,the limit of quantitation of chloramphenicol was 20 pg/mL（0.2 μg/kg honey）.展开更多
Keto-enol tautomers of curcumin were confirmed by reversed-phase liquid chromatography（RPLC）/ hybrid quadrupole ion trap/time-of-flight mass spectrometry（QIT/TOFMS）.Tautomers gave different MS/MS spectra in negati...Keto-enol tautomers of curcumin were confirmed by reversed-phase liquid chromatography（RPLC）/ hybrid quadrupole ion trap/time-of-flight mass spectrometry（QIT/TOFMS）.Tautomers gave different MS/MS spectra in negative mode.Different mass spectra were also obtained by hydrogen/deuterium exchange LC/MS/MS in positive mode.Our results suggest that enol form is the major form in the solution（water/acetonitrile）.展开更多
基金supported by the National Natural Science Foundation of China(Nos.90813015,20935002)
文摘Monolithic silica spin column extraction （MonoSpin-SPE） was developed as a simple, sensitive, and eco-friendly pretreatment method which combined with ultra-fast liquid chromatography-mass spectrometry （UFLC-MS） to determine the levels of six phthalate esters, dimethyl- （DMP）, diethyl- （DEP）, dipropyl- [ DPrP], butyl-benzyl- （BBP）, dicyclohexyl- （DcHP）, and di-n-octyl-（DOP） phthalate in physiological saline samples. Under optimized experimental conditions, the method was linear in the following ranges： 0.2- 50 μg/L for DMP, DEP, DPrP, DcHP and DOP; 5- 100 μg/L for BBP. The correlation coefficients （R2 ） were in the range of 0. 9951 - 0. 9995 for all the analytes and the limits of detection （LODs） and limits of quantification （LOQs） were in the ranges of 0.02 - 0.9 μg/L and 0.08 - 2.7μg/L, respectively. The pretreatment process showed good reproducibility with inter-day and intra-day relative standard deviations （RSDs） below 8.5% and 11.2%, respectively. This method was used to determine the levels of six phthalate esters in physiological saline samples and the recoveries ranged from 71.2% to 107.3%. DMP and DEP were found in actual physical saline samples （brand A and brand B）.
基金supported by the National Natural Science Foundation of China(No.21227006)the Research Fund for the Doctoral Program of Higher Education(No.20110002110052)
文摘hloramphenicol is an antibiotic and one of the potential contaminants in honey.Solid-phase extraction is the key pretreatment procedure for analysis of chloramphenicol in honey.In this work,an on-line pretreatment liquid chromatography-tandem mass spectrometer system for sensitive,reliable and higher throughput analysis was developed.With the methylcellulose-immobilized reversed-phase column,sugars in a honey sample were efficiently removed in 1 min.As a result,the limit of quantitation of chloramphenicol was 20 pg/mL（0.2 μg/kg honey）.
基金supported by the Research Fund for the Doctoral Program of Higher Education(No.20110002110052)
文摘Keto-enol tautomers of curcumin were confirmed by reversed-phase liquid chromatography（RPLC）/ hybrid quadrupole ion trap/time-of-flight mass spectrometry（QIT/TOFMS）.Tautomers gave different MS/MS spectra in negative mode.Different mass spectra were also obtained by hydrogen/deuterium exchange LC/MS/MS in positive mode.Our results suggest that enol form is the major form in the solution（water/acetonitrile）.
