Chromatography Online
A recent study aimed to directly compare the changes in serum metabolites among very low birth-rate (VLBW) infants following the administration of the soybean oil-based lipid emulsion and soybean oil, medium-chain triglycerides, olive oil, and fish oil (SMOF) lipid emulsion using untargeted metabolomics techniques.
The Flame Ionization Detector - Chromatography Online
Dec 1, 2005 · John V. Hinshaw Although these ionization detectors share several features, their implementations differ significantly. Detector performance characteristics (sensitivity, minimum detectable quantity, linearity, and selectivity) are affected strongly by the type of ionization mechanism, the internal electrode arrangement, and the electronics.
Ultraviolet Detectors: Perspectives, Principles, and Practices
Oct 1, 2019 · Requirements and Desirable Characteristics of UV Detectors. Table II summarizes the requirements and desirable characteristics of a modern UV detector (VWD or DAD), followed by a discussion of historical perspectives, optical designs, operating principles, and common operation and maintenance procedures.
LCGC North America - Chromatography Online
Practical advice, tutorials, and peer-reviewed research on liquid chromatography (HPLC), gas chromatography (GC), mass spectrometry (MS) and related techniques.
Troubleshooting Basics, Part IV: Peak Shape Problems
Jul 1, 2012 · Figure 4: Peak fronting for two consecutive injections: (a) 527 and (b) 528. If All Peaks Tail. When all peaks in the chromatogram tail or are split or doubled, as in Figure 5, this is a symptom of a problem that happens at the inlet of …
Chromatography Fundamentals, Part VIII: The Meaning and …
Nov 1, 2019 · The effectiveness of a separation can be quantified by measuring the resolution. This article explains the factors influencing resolution and the equation for predicting the required number of theoretical plates to obtain a given esolution.
Understanding Ion-Exchange Chromatography
Aug 1, 2012 · Ion-exchange chromatography (IEC) is based on the different affinities of analyte and eluent counterions for the oppositely charged ionic functional groups on the stationary-phase surface of an exchange resin. Depending on the charge of the surface electrostatic groups, the resin could be either an anion exchanger (positively charged stationary phase) or a cation exchanger (negatively charged ...
Back to Basics: The Role of pH in Retention and Selectivity
Jan 1, 2017 · Figure 1: Simulated chromatograms for a mixture of six neutral compounds (unlabeled peaks between approximately 3 and 9 min) and two carboxylic acids at (a) pH 7.0 and (b) pH 3.0. The peak at approximately 0.75 min is t 0.. When ionizable analytes are present, dramatic changes in retention can take place when the mobile-phase pH is altered.
LCGC Europe - Chromatography Online
Practical advice, tutorials, and peer-reviewed research on liquid chromatography (HPLC), gas chromatography (GC), mass spectrometry (MS) and related techniques.
Calibration Curves, Part IV: Choosing the Appropriate Model
Jun 1, 2009 · Figure 1: External standard calibration plot from data of Table I. Internal Standardization. External standardization works well when sample preparation steps are simple and the injection volume precision is good.