Incurred sample reanalysis: enhancing the Bland-Altman approach with tolerance intervals.

This article describes the need for incurred sample reanalysis and suggests that the combination of a Bland-Altman plot and tolerance intervals can provide a visual evaluation of method performance. It also shows how the proposed combination is a tool that may be of value in determining minimum sample size. An example dataset is worked through in its entirety so that a reader unfamiliar with the topic can gain sufficient information to analyze their own data.

Multiplexed rectilinear ion trap mass spectrometer for high-throughput analysis.

A multichannel mass spectrometer based on the rectilinear ion trap (RIT) analyzer was designed and constructed for simultaneous high-throughput analysis of multiple samples. The instrument features four parallel ion source/mass analyzer/detector channels assembled in a single vacuum chamber and operated using a common set of control electronics, including a single rf amplifier and transformer coil. This multiplexed RIT mass spectrometer employs an array of four millimeter-sized ion traps (x(o) = 5.

Co-occurrence of boundary and resonance ejection in a multiplexed rectilinear ion trap mass spectrometer.

A method is reported for evaluating ion trap mass analyzers by selection of operating conditions under which both boundary and resonance ejection peaks occur in a single mass scan. The choice of frequency and amplitude of the auxiliary waveform applied for resonance ejection can be such as to produce a resonance ejection mass spectrum with unit resolution or, under selected conditions, signals attributable to both boundary and resonance ejection in a single mass scan. The contrasting mass resolution associated with these two ejection processes is evident in these data.

High-throughput miniature cylindrical ion trap array mass spectrometer.

A fully multiplexed cylindrical ion trap (CIT) array mass spectrometer with four parallel ion source/mass analyzer/detector channels has been built to allow simultaneous high-throughput analysis of multiple samples. A multielement external chemical ionization/electron ionization source was coupled to a parallel array of CITs each of equal size (internal radius 2.5 mm), and the signal was recorded using an array of four miniature (2-mm inner diameter) electron multipliers.