Evaluation of lifetime and analytical performance of gas chromatographic inlet septa for analysis of reactive semivolatile organic compounds

Westland, Jessica; Organtini, Kari L.; Dorman, Frank L.

doi:10.1016/j.chroma.2012.03.030

Cited by 4 publications

(1 citation statement)

References 4 publications

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“…When matrix contami-nated samples are injected, high boiling residues accumulate in the liner [42]. These are known to promote the breakdown of several OCPs, for example endrin and DDT, thereby leading to underestimations [43] [44] [45]. This phenomenon has been used to judge the performance of inert liners and capillary columns [46] [47] [48].…”

Section: Use Of Internal Standards and Gc Linersmentioning

confidence: 99%

Efficiency Evaluation of Extraction Methods for Analysis of OCPs and PCBs in Soils of Varying TOC

Mülow-Stollin¹,

Lehnik-Habrink²,

Kluge³

et al. 2017

JEP

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Organochlorine pesticides and polychlorinated biphenyls are toxic, carcinogenic, and have a high potential for bioaccumulation. Due to their stability, they are still considered an environmental problem even though the use of most of them has been phased out several decades ago. Soil is a matrix which can retain these contaminants to a great extent. This ability is often associated with the total organic carbon content (TOC). In order to judge the pollution status of soil and to make monitoring data more easily comparable a simple, yet robust extraction method is needed. Agitation solid-liquid-extraction is well suited for this purpose. However, the influence of TOC on the analyte recovery has to be known. For the presented study, 12 organochlorine pesticides and 7 polychlorinated biphenyls were spiked into four model soils with organic carbon contents between 1.6% -13.3%. The matrices were extracted using solid-liquid extraction between 45 minutes and 16 hours. For comparison, all soils were also extracted using pressurised liquid extraction and Soxhlet extraction. After clean-up the extracts were measured using a gas chromatography-mass spectrometry (GC-MS) system. Statistical analysis of the results implied that the TOC content of the soils did not have significant influence on the extraction efficiency. A longer solid-liquid extraction time did not necessarily increase analyte recovery: Extraction for one hour resulted in 88% recovery while 16 hour extraction led to 89%. Thus, the efficiency of all the methods was comparable for all model soils. Additional investigations regarding GC liner performance highlighted the need for isotopically labelled standards during the analysis of thermolabile pesticides.

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Section: Use Of Internal Standards and Gc Linersmentioning

confidence: 99%

Efficiency Evaluation of Extraction Methods for Analysis of OCPs and PCBs in Soils of Varying TOC

Mülow-Stollin¹,

Lehnik-Habrink²,

Kluge³

et al. 2017

JEP

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Factors influencing the in situ formation of Δ9‐THC from cannabidiol during GC–MS analysis

Cheng,

Kerrigan

2023

Drug Testing and Analysis

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Gas chromatography–mass spectrometry (GC‐MS) is widely used for the identification of cannabinoids in seized plant material. Conditions used for instrumental analysis should maximize decarboxylation, while minimizing the in situ production of Δ9‐THC inside the GC inlet. In this study, decarboxylation of the acidic Δ9‐THC precursor and in situ degradation of cannabidiol (CBD) were investigated using seven commercial GC liners with different deactivation chemistries and geometries. While the inlet temperature was previously optimized at 250°C in a previously validated assay, we systematically examined the temperature‐dependent decarboxylation of tetrahydrocannabinolic acid‐A (Δ9‐THCA‐A) and cyclization of CBD between 230°C and 310°C using different liners using favorable and unfavorable conditions. Significant differences in decarboxylation rate and CBD cyclization were observed between different liner types. While no temperature‐dependent differences in decarboxylation rate were observed within liner type, liner‐dependent differences were observed (α = 0.05), particularly between those with different geometry. In contrast, temperature and liner‐dependent differences were observed for in situ formation of Δ9‐THC (α = 0.05). This was influenced by liner geometry and to a smaller extent by surface deactivation. Effects were exacerbated with liner usage. While significant differences were observed using new and used GC liners, differences between liners of the same type but different lot numbers were not observed. Inter‐instrument differences using the same liner were also evaluated and had minimal effect. Liner‐ and temperature‐dependent effects were also confirmed using more than 20 cannabis plant extracts. Careful selection of liner, inlet conditions, and regular preventive maintenance can mitigate the risks associated with in situ formation Δ9‐THC from CBD.

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Optimization of peak area precision of a GC–MS drug screening method using a nonparametric sign test

et al. 2019

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Evaluation of lifetime and analytical performance of gas chromatographic inlet septa for analysis of reactive semivolatile organic compounds

Cited by 4 publications

References 4 publications

Efficiency Evaluation of Extraction Methods for Analysis of OCPs and PCBs in Soils of Varying TOC

Efficiency Evaluation of Extraction Methods for Analysis of OCPs and PCBs in Soils of Varying TOC

Factors influencing the in situ formation of Δ9‐THC from cannabidiol during GC–MS analysis

Optimization of peak area precision of a GC–MS drug screening method using a nonparametric sign test

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