Use of SEC–ICP–MS with a collision cell for determining the interaction of chromium with DNA extracted from metal-contaminated soils

Abstract

The potential of chromium to bind to DNA isolated directly from soil microbial communities was investigated in this study. An analytical scheme was developed to distinguish between chromium bound to DNA and its fragments or chromium contained elsewhere in an environmental DNA extract. DNA was extracted from chromium-contaminated soils and purified using DNA clean-up resins. Size-exclusion chromatography was employed due to its advantages in the separation and molecular weight approximation of large biomolecules. It was coupled with two on-line detection systems (spectrophotometric and inductively coupled plasma mass spectrometric) to study the binding of chromium to DNA or other components in a DNA extract. A collision cell was pressurized with helium to remove diatomic and polyatomic interferents resulting from the chosen mobile phase. Chromium peaks were observed in both the large and small molecular weight regions of the chromatogram; to further confirm that the environmentally extracted DNA contained Cr, the subsequently purified DNA was examined for total Cr using flow injection ICP-MS to accommodate small sample volumes. DNA samples isolated from the two soils examined contained 0.5-0.7 ppb Cr, indicating that DNA isolated directly from a chromium-contaminated soil has chromium bound to the nucleic acids.

Atomic spectrometry update. Environmental analysis

“…In-house Canadian peat reference samples, previously characterised by TIMS, and BCR CRM 482 Lichen were used to evaluate the method. Internal (within run) and external (between runs) precisions for LA-MC-ICP-MS were found to be o1.1% and o0.3%, respectively, for both 207 Pb/ 206 Pb and 208 Pb/ 206 Pb ratios. As expected, ratios obtained by LA-Q-ICP-MS had poorer precisions of o14.3% within run and 2.9% between runs.…”

Aportes Y Dificultades De La Metagenómica De Suelos Y Su Impacto en La Agricultura.

“…Se han reportado algunos métodos para eliminar compuestos aromáticos como sustancias húmicas y polifenoles de las muestras del suelo utilizando resinas de intercambio catiónico y detergentes, polivinilpirrolidona (PVP), hidroxiapatita y carbono activado, pero la purificación compromete el rendimiento de ADN (Hemmat-Jou et al, 2018). Otros contaminantes como el cobre pueden estar presentes en las extracciones de ADN de suelos contaminados como lo demostró Sabrina R. Muller-Spitz y colaboradores (Mueller-Spitz et al, 2006), los cuales también interfieren con las modificaciones enzimáticas.…”

Fractionation and Speciation of Trace Elements in Soil Solution

“…However, SEC can also be directly coupled to ICP-MS (SEC-ICP-MS), which allows a direct fractionation of trace elements into different associated particle size fractions. As a result, this technique has also been used for the analysis of trace elements associated with particles and molecules of different sizes, mainly metalloproteins, but also dissolved organic material, both in soil extracts/solutions and groundwater [35][36][37][38]. Although SEC is most commonly used for the separation of relatively large compounds such as polymers and biopolymers, it can be used for the separation of compounds of intermediate molecular weight as well.…”