March 2024

This installment examines a sample preparation survey, focusing on sample sizes, laboratory techniques used, automation, the use of solid-phase extraction (SPE) devices (cartridges, disks, plates, tips), SPE chemistries and selection criteria, and problems encountered in SPE.

The concept of gradient delay volume (GDV) in liquid chromatography (LC) poses challenges for both beginners and experienced practitioners. The GDV, which affects the arrival time of mobile phase composition changes at the column inlet, can have a significant impact on method throughput, influencing the time required for mobile phase changes at both the beginning and end of the LC method. Different pump designs and column characteristics affect efficient use of the available analysis time, as well as overall throughput. Notably, achieving repeatable equilibration, rather than full equilibration of LC columns following mobile phase gradients, is often sufficient for many LC applications, which can also be leveraged to increase method throughput.

In this installment, we examine several of the common parameters that can affect automated peak integration and the resulting peak areas. We will consider how the data system detects the beginning and end of the peak, how it determines the peak maximum, how real peaks are differentiated from noise, and how signals at individual time intervals are summed to generate the peak area.

In this column, a fast, simplified procedure for determining simple sugars in fruit juices is described.

This article describes a liquid chromatography–tandem mass spectrometry (LC–MS/MS) method for the analysis of coumarin in various tobacco matrices and electronic cigarette (E-cig) liquids, and highlights the importance of evaluating different MS/MS transitions of an analyte in complex sample matrices to overcome matrix effects. Matrix interfering components were separated from analyte using a C18 ultrahigh-pressure liquid chromatography (UHPLC) column with a larger inner diameter (3.0 mm, or 4.6 mm). Matrix suppressions on analyte responses were corrected by isotope dilution. Four different MS/MS transitions of coumarin were studied in each sample matrix to select a suitable MS/MS transition for analyte quantification based on matrix effects on each MS/MS transition. The method was validated using different tobacco matrices and E-cig liquids.

This year’s conference highlighted how analytical scientists are exchanging research to tackle some of the world’s most critical problems.

Click here to open LCGC International March 2024 North America issue, Volume 1, Number 3, in an interactive PDF format.