Normal phase liquid chromatography coupled to quadrupole time of flight atmospheric pressure chemical ionization mass spectrometry for separation, detection and mass spectrometric profiling of neutral sphingolipids and cholesterol

Development and validation of sensitive LC-MS/MS assays for quantification of HP-#x03B2;-CD in human plasma and CSF

“…This technique is called in-source fragmentation-or in-source collisioninduced dissociation. In-source fragmentation has been used in structural elucidation ( 14 ), compound identifi cation (15)(16)(17), compound profi ling ( 18 ), and bioanalysis ( 19 ). In-source fragmentation of HP-␤ -CD, which was promoted by increasing declustering potentials on a 4000QTRAP mass spectrometer, led to glycosidic-bond cleavage and simultaneous fragmentation of all the HP-␤ -CD …”

Large-scaled human serum sphingolipid profiling by using reversed-phase liquid chromatography coupled with dynamic multiple reaction monitoring of mass spectrometry: Method development and application in hepatocellular carcinoma

“…Besides, efforts have been made, by applying mild alkaline hydrolysis [16,18,19,23,32], or solid phase extraction (SPE) [20,33], aimed at reduced ion suppression, especially in a shotgun pattern. Nevertheless, these methods were hampered either by limited throughput in using SPE, or by inconstant factors of dripping loss or possible interfering protein in using chloroform/methanol/water.…”

“…Efficient separation by ultra high performance RPLC based on chain length and unsaturation, is helpful in a dynamic MRM method embracing up to 90 analytes, compared with by NPLC [18,19,37], or HILIC [21,31], where separation is based on polar group and coelution occurs for each subcategory. Fig.…”

“…They are SM41:2 (SM (d17:1/24:1) and SM (d18:2/23:0)), SM42:2 (SM (d18:1/24:1) and SM (d18:2/24:0)) as highlighted in Table S1. In contrast to other methods applying NPLC [18,19,37] or HILIC [21,31], it also facilitated quantification by avoiding isotope correction. Moreover, a linear regression model could be constructed by plotting carbon number v.s.…”

“…In comparison, LC-MS/MS based methods dramatically enhanced sensitivity, structural-specificity and accuracy for detection of intact sphingolipid species. By far, a large number of LC-MS-based methods with various extraction protocols have been established, using normal phase liquid chromatography (NPLC), hydrophilic interaction liquid chromatography (HILIC), or reversed-phase liquid chromatography (RPLC) for sphingolipid separation, coupled with multiple reaction monitoring (MRM) acquisition via electrospray ionization (ESI) or atmospheric-pressure chemical ionization (APCI) [15][16][17][18][19][20][21][22][23]. Nevertheless, no method has been capable of a comprehensive profiling of a large spectrum of sphigolipid species/subcategories in a single method, let along in a single run.…”