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
2005年12月1日 · 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
2019年10月1日 · 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
2012年7月1日 · 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 …
Mobile-Phase Degassing: What, Why, and How - Chromatography …
2014年7月1日 · Figure 3: The effect of helium and air dissolved in the mobile phase on the response of naphthalene: (a) UV detection at 254 nm; (b) fluorescence detection with 250-nm excitation and 340-nm emission.
LCGC International - Chromatography Online
Practical advice, tutorials, and peer-reviewed research on liquid chromatography (HPLC), gas chromatography (GC), mass spectrometry (MS) and related techniques.
How Do Your Peaks Measure Up? - Chromatography Online
2013年10月1日 · Asymmetry: Only computer-generated Gaussian peak shapes (such as seen here) are perfectly symmetrical from front to back.Real chromatographic peaks have some degree of asymmetry; their front and back halves are not the same shape. Extra-column dead volumes, peak mass overloading, and reversible adsorption effects are some of the principal causes of peak asymmetry.
Back to Basics: The Role of pH in Retention and Selectivity
2017年1月1日 · 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.
Chromatography Fundamentals, Part VIII: The Meaning and …
2019年11月1日 · 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.