RESUMO
This method is a simple, cost-free, and reliable approach for the removal of N2 interference on a CO analyte when analysing nitrogen-rich (>0.5% w/w) samples by Elemental Analysis Isotope Ratio Mass Spectrometry. Specifically, the isobaric interference on m/z 30 is eliminated using only the open split of the Thermo Scientific ConFlo IV Universal Interface Device, improving the analytical workflow when using a static temperature Gas Chromatography (GC) column. It simplifies the N2 diversion methods described in recent decades. When applied, the method described here:â¢Provides sufficient baseline resolution between the N2 and CO analytes, to permit quantitative N2 diversion, using an extended length packed GC column;â¢Quantitatively eliminates all N2 analyte from the analytical gas stream ensuring that no N2 enters the ion source and therefore no isobaric interference is produced on m/z 30 ion trace of the CO analyte;â¢Allows reproducible measurement of δ18O values from nitrogen-rich sample materials without a N2 isobaric interference, where the CO analyte is measured on the analytical baseline that it was produced on in the reactor (i.e., no addition make-up helium or new baseline of pure helium for the CO analyte).
RESUMO
In contrast to the validated scales for face-to-face assessment of negative symptoms, no widely accepted tools currently exist for remote monitoring of negative symptoms. Remote assessment of negative symptoms can be broadly divided into 3 categories: (1) remote administration of an existing negative-symptom scale by a clinician, in real time, using videoconference technology to communicate with the patient; (2) direct inference of negative symptoms through detection and analysis of the patient's voice, appearance, or activity by way of the patient's smartphone or other device; and (3) ecological momentary assessment, in which the patient self-reports their condition upon receipt of periodic prompts from a smartphone or other device during their daily routine. These modalities vary in cost, technological complexity, and applicability to the different negative-symptom domains. Each modality has unique strengths, weaknesses, and issues with validation. As a result, an optimal solution may be more likely to employ several techniques than to use a single tool. For remote assessment of negative symptoms to be adopted as primary or secondary endpoints in regulated clinical trials, appropriate psychometric standards will need to be met. Standards for substituting 1 set of measures for another, as well as what constitutes a "gold" reference standard, will need to be precisely defined and a process for defining them developed. Despite over 4 decades of progress toward this goal, significant work remains to be done before clinical trials addressing negative symptoms can utilize remotely assessed secondary or primary outcome measures.