Thermal degradation of metabolites in urine using multiple isotope-labelled internal standards for off-line GC metabolomics - effects of injector and oven temperatures

TY - JOUR

T1 - Thermal degradation of metabolites in urine using multiple isotope-labelled internal standards for off-line GC metabolomics - effects of injector and oven temperatures

AU - Tsochatzis, Emmanouil

AU - Nebel, Caroline

AU - Danielsen, Marianne

AU - Sundekilde, Ulrik Kræmer

AU - Dalsgaard, Trine Kastrup

PY - 2021/9/1

Y1 - 2021/9/1

N2 - Thermal processes are widely used in small molecule chemical analysis and metabolomics for derivatization, vaporization, chromatography, and ionization, especially in gas chromatography mass spectrometry (GC/MS). An optimized derivatization protocol has been successfully applied using multiple isotope labelled analytical internal standards of selected deuterated and 13C selected compounds, covering a range of different groups of metabolites for non- automated GC metabolomics (off-line). Moreover, the study was also realized in a pooled urine sample, following metabolic profiling. A study of thermal degradation of metabolites due to GC inlet and oven programs (fast, slow) was performed, where the results indicated that both GC oven programs (fast and slow) negatively affected the thermal stability of the metabolites, while the fast-ramp GC program also suppressed MS signals. However, the use of multiple internal standards can overcome this drawback. The application of extended temperature ramp GC program presented identical behaviour on metabolite stability and better chromatographic separation combined with much lower signal suppression, compared to a short temperature ramp program. No effects were observed for organic acids, fatty acids, sugars and sugar alcohols, while significant differences were observed for amino acids. GC metabolomics is a strong tool that can facilitate analysis, but special attention is required for sampling handling and heating, before and during the GC analysis. The use andapplication of multiple multi-group internal standards is highly recommended.

AB - Thermal processes are widely used in small molecule chemical analysis and metabolomics for derivatization, vaporization, chromatography, and ionization, especially in gas chromatography mass spectrometry (GC/MS). An optimized derivatization protocol has been successfully applied using multiple isotope labelled analytical internal standards of selected deuterated and 13C selected compounds, covering a range of different groups of metabolites for non- automated GC metabolomics (off-line). Moreover, the study was also realized in a pooled urine sample, following metabolic profiling. A study of thermal degradation of metabolites due to GC inlet and oven programs (fast, slow) was performed, where the results indicated that both GC oven programs (fast and slow) negatively affected the thermal stability of the metabolites, while the fast-ramp GC program also suppressed MS signals. However, the use of multiple internal standards can overcome this drawback. The application of extended temperature ramp GC program presented identical behaviour on metabolite stability and better chromatographic separation combined with much lower signal suppression, compared to a short temperature ramp program. No effects were observed for organic acids, fatty acids, sugars and sugar alcohols, while significant differences were observed for amino acids. GC metabolomics is a strong tool that can facilitate analysis, but special attention is required for sampling handling and heating, before and during the GC analysis. The use andapplication of multiple multi-group internal standards is highly recommended.

KW - GC-QToF MS

KW - Metabolomics

KW - Temperature ramping

KW - Derivatization

KW - Thermal degradation

KW - Internal standards

UR - http://www.scopus.com/inward/record.url?scp=85114834785&partnerID=8YFLogxK

U2 - 10.1016/j.jchromb.2021.122902

DO - 10.1016/j.jchromb.2021.122902

M3 - Journal article

C2 - 34530307

SN - 1570-0232

VL - 1181

JO - Journal of Chromatography B: Analytical Technologies in the Biomedical and Life Sciences

JF - Journal of Chromatography B: Analytical Technologies in the Biomedical and Life Sciences

M1 - 122902

ER -