Target, Suspect and Non-Target Screening of Silylated Derivatives of Polar Compounds Based on Single Ion Monitoring GC-MS

Abstract

There is growing interest in determining the unidentified peaks within a sample spectra besides the analytes of interest. Availability of reference standards and hyphenated instruments has been a key and limiting factor in the rapid determination of emerging pollutants in the environment. In this work, polar compounds were silylated and analyzed with gas chromatography mass spectrometry (GC-MS) to determine the abundant fragments within the single ion monitoring (SIM) mode and methodology. Detection limits and recoveries of the compounds were established in river water, wastewater, biosolid and sediment matrices. Then, specific types of polar compounds that are classified as emerging contaminants, pharmaceuticals and personal care products, in the environment were targeted in the Mgeni and Msunduzi Rivers. We also performed suspect and non-target analysis screening to identify several other polar compounds in these rivers. A total of 12 compounds were quantified out of approximately 50 detected emerging contaminants in the Mgeni and Msunduzi Rivers. This study is significant for Africa, where the studies of emerging contaminants are limited and not usually prioritized.

Isolation and Characterization of a New Endophytic Actinobacterium Streptomyces californicus Strain ADR1 as a Promising Source of Anti-Bacterial, Anti-Biofilm and Antioxidant Metabolites

“…The compounds were assigned probable identities based on similarity index (SI) value, generated from the mass spectral analyses of the test compounds and their comparison with the reference compounds listed in the NIST and Wiley library. An SI of more than 85 was considered for assignment of probable identity to the compounds [72]. Out of the total 30 peaks detected in the chromatogram, 20 peaks were specific to the culture S. californicus ADR1 while rest of the peaks were related to the production media and the solvent control ( Figure S1).…”

Risk Assessment of Personal Care Products, Pharmaceuticals, and Stimulants in Mgeni and Msunduzi Rivers, KwaZulu-Natal, South Africa

“…Water and sediments samples were collected along Mgeni and Msunduzi rivers located in Kwa-Zulu Natal, South Africa (Figure 1) (Gumbi et al, 2019). These two rivers pass through towns, agricultural fields, wastewater effluent discharge sites, landfills, hospitals, and villages.…”

“…A preliminary risk characterization in the different environmental compartments was based on a tiered system FIGURE 1 | Sampling area of the Mgeni and Msunduzi rivers in KwaZulu-Natal, South Africa. Grab samples were collected at all points and using the developed method described in this work (map was drawn using GIS software shapefile) (Gumbi et al, 2019).…”

“…Therefore, their isolation at different pH values needed to be optimized. The aqueous distribution of compounds was investigated using water adjusted at three different pH values (2, 7, and 9) with HCl or NaOH as shown in (Gumbi et al, 2017a(Gumbi et al, ,b, 2019. Spiked double distilled water (10 µg L −1 ), aliquots of 200 ml, adjusted to pH 2, 7, and 9 were passed through Oasis HLB at flow rates between 5 and 8 ml min −1 .…”

Use of carbonyldiimidazole as a derivatization agent for the detection of pinacolyl alcohol, a forensic marker for Soman, by EI‐GC–MS and LC‐HRMS in official OPCW proficiency test matrices

“…The chemical modification of analytes for enhancing their detection and analysis by various analytical methods is common practice in analytical and forensic laboratories [1,2]. These chemical modifications are a cornerstone component particularly in the realm of gas chromatography-mass spectrometry (GC-MS), wherein polar compounds are specifically modified to yield derivatives possessing superior volatility and chromatographic profiles relative to the starting, unmodified analyte [3].…”