Comprehensive two-dimensional gas chromatography (GC × GC) is one of the most powerful analytical tools for the analysis of organic compounds in complex matrices. The technique is based on continuous collection of the effluent from a GC column and periodic reinjection of small portions of the effluent to a second column of different properties. The process is repeated at a rate fast enough that...

OBJECTIVE This study was designed to evaluate vitamin D status with separate determination of 25-OH D2 and 25-OH D3 and its relationship to vitamin D binding protein (VDBP) in patients with chronic kidney disease (CKD) and long-term haemodialysis patients (HD). METHODS 45 CKD patients, 103 HD patients, and 25 controls (C) were included. Plasma vitamin D concentrations were determined using ch...

the composition of the essential oils of teucrium chamaedrys l. belongs to the family lamiaceae, it is growing wild in the margin of mountainous roads of arid and cold climate of north iran. in this research, essential oils of teucrium chamaedrys l., extracted and measured at the different location by different methods of distillationand then were analyzed by gc and gc/ms. investigation and com...

Recent application of photo-ionization (PI) coupled with GC×GC-HRTOF/MS for authentic standard mix called century mix along with several groups of petrochemical samples demonstrated PI as an effective soft-ionization technique to characterize volatile mixtures particularly, hydrocarbons [1]. This soft-ionization technology was shown to enhance analyte speciation by providing both molecular ions...

Mismatch repair (MMR) and germline E-cadherin (CDH1) mutations are two of the major pathways of carcinogenesis in familial gastric cancer (GC). A total of 260 sporadic and 66 familial GC patients were enrolled and molecular and survival differences were compared. Familial GC patients had earlier onset and were diagnosed at an earlier stage and had both a better 5-year overall survival rate and ...

A new approach of flow modulation comprehensive two-dimensional gas chromatography-mass spectrometry (GC x GC-MS) with supersonic molecular beam (SMB) and a quadrupole mass analyzer is presented. Flow modulation uniquely enables GC x GC-MS to be achieved even with the limited scan speed of quadrupole MS, and its 20 ml/min column flow rate is handled, splitless, by the SMB interface. Flow modula...