HPLC

John Dolan looks at ways to get to the root of some of the most common problems encountered in the lab.

In the inaugural installment of his new column, LCGC veteran Michael Swartz provides an overview of some of the newer LC technology used in contemporary LC laboratories.

LCGC provides its annual editorial index as a resource for readers.

A fast clean and simple method to determine three organotin compounds in environmental samples is described

Kevin Schug talks to Harold McNair about his illustrious career in chromatography

Guest author Uwe Neue develops the principle of kinetic plots from scratch to make them more accessible to a wider audience.

The authors present the first installment in their examination of the basics of method validation.

In this installment of "Column Watch," Ron Majors looks at the results of a recent HPLC column survey conducted by LCGC North America.

The authors examine some critical factors with regard to buffers in LC and LC-MS research.

In Part II, we review MS ionization suppression; column, pH, and temperature selection; and system peaks and column equilibration issues associated with the use of five volatile perfluorocarboxylic acid reagents in LC.

To meet system suitability requirements, chromatographers might need to make adjustments to the high performance liquid chromatography (HPLC) operating conditions.

What's the best way to integrate a peak?

An optimization strategy to obtain the best possible performance in the shortest analysis time for comprehensive off-line 2D-LC.

This month's column discusses the type of problems one can encounter when using methods supplied to us by other.

Ron Majors provides first-hand coverage of some of the technology and application advances reported at HPLC 2009.

The former "Milestones in Chromatography" editor returns to give readers the story of his time in the field.

October 2006. The authors demonstrate the use of multiple-injection affinity capillary electrophoresis (MIACE) and several variations to MIACE to determine binding constants between the glycopeptide antibotics vancomycin, ristocetin, and teicoplanin from Streptomyces orientalis, Nocardia lurida, and Actinoplanes teichomyceticus, respectively, and D-Ala-D-Ala terminus peptides.

This is the fifth and final installment in a series of columns about various aspects of calibration of LC methods.

This is the third installment in a series of LC Troubleshooting columns that focus on calibration curves used for LC methods. Here, John Dolan considers some alternate ways to look at the data to determine if they appear to be normal or are trying to tell us something is amiss.

Ron Majors brings readers the second part of his yearly review of all that was new and innovative at the annual Pittsburgh Conference.

Several approaches for purifying difficult samples more efficiently for discovery research support are mentioned in this paper. These approaches use mass triggered HPLC on various specialty columns.

In part two of this series, John Dolan looks at the signal-to-noise ratio and its relationship to uncertainty in a measurement.

A fast enantiomeric separation of a chiral aromatic amine was achieved, using ultra high pressure liquid chromatography and highly sulfated β-cyclodextrin (S-β-CD) as a chiral additive in the mobile phase. The stationary phase consisted of a core shell support with a particle size of 2.7 µm. Under these conditions the baseline separation was obtained within 2.5 min. The influence of the concentration of the additive, along with the thermodynamics of the separation, were studied. Molecular mechanics calculations were consistent with the experimental data for the order of elution, providing further evidence of these interactions. The enantiomeric separation at high temperature (90 °C) using only water as mobile phase also was achieved for the first time.

Due to economic crisis all over the world it is a time of cost-friendly analyses. Superficially porous and monolithic columns are the tools to serve this purpose. These columns are new generation and can be used for ultrafast separations. This article describes the state-of-the-art for these stationary phases for high performance liquid chromatography (HPLC). The emphasis has been placed on their preparation, properties, applications, comparison, and future perspectives. It has been observed that superficially porous columns may be the choice of future for ultrafast separations.

The use and evolution of the two-dimensional liquid chromatography (LCxLC) technique is explored with respect to instrumentation and applications.

During the last four to five years, chromatographers have witnessed some significant advances in technology, from the instrument perspective, with systems operating up to 15,000 psi using new and significantly improved detectors, sometimes operating in multiple dimensions, and from the column perspective, with smaller particle sizes and new chemistries and configurations.

Over the past several years, charged aerosol detection (CAD) has become a widely used technology in the pharmaceutical laboratory. From formulation to stability and even quality control, many analysts are turning to this technology due to its advantages of sensitivity, ease of use, dynamic range, and applicability to a wide range of analyses in the drug development process. In this article, we will examine the operation and use of CAD in a regulated environment, briefly address method development and validation specifics, and highlight a few examples illustrating some of its advantages when used in the pharmaceutical laboratory.

An overview of contemporary techniques in environmental analysis.

A rapid and simple high performance liquid chromatography (HPLC) method with basic extraction assays was developed to investigate free diazepam levels in the plasma and urine samples of patients medicated with this drug for the management of alcohol withdrawal syndrome. The HPLC analysis was optimized and evaluated for linearity, imprecision, recovery, detection and quantification limits. The method showed linearity between 50–500 ng/mL (r2 ≥ 0.990). Coefficients of variations (%CV) were calculated to be in the range of 1.77–9.60. According to ICH guidelines, theoretical limits of detection (LOD) and quantification (LOQ) for plasma and urine were calculated as 8.3 ng/mL, 27.5 ng/mL and 8.2 ng/mL, 26 ng/mL respectively. Diazepam monitoring in plasma and urine displayed remarkable variations. The importance of adjusting doses according to individual requirements and the routine monitoring of plasma or urine for patients under medication is highlighted.

The primary goal of early phase development is to gain a fundamental knowledge of the chemistry of drug substances and drug products to facilitate optimization of synthetic schemes and drug product formulations. At the same time, methods are required for release and stability studies to support clinical trials. Ultimately, the knowledge gained during early development translates into designing control methods for commercial supplies. Our approach to meeting this challenge is based upon the use of a primary method along with orthogonal methods. This paper will discuss the overall strategy, with an emphasis on the chromatographic conditions selected to provide systematic othogonality for a broad range of drugs. Case studies will be presented to demonstrate the utility of orthogonal methods to resolve issues that could not have been addressed using a single release and stability method.