News from LabRulezGCMS Library - Week 11, 2025

Our Library never stops expanding. What are the most recent contributions to LabRulezGCMS Library in the week of 10th March 2025? Check out new documents from the field of the gas phase, especially GC and GC/MS techniques!

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This week we bring you poster by Agilent Technologies and application notes by Shimadzu and Thermo Fisher Scientific!

1. Agilent Technologies (ASMS 2024): Automated Sample Preparation and Analysis of OCPs in Drinking Water

• Poster
• Full PDF for download

The Analysis of Organochlorine Pesticides (OCP’s) in drinking water is generally performed by manual liquid-liquid extraction with a concentration step performed before analysis by triple quadrupole GC/MS. Traditionally, volumes as high as 500 and 1000 mL are used and at least 100 to 200 mL of water sample is required with often over 25 mL of extraction solvent needed to extract. Hence, an additional concentration step via evaporation becomes needed.

Benefits of Automation

Sample preparation automation provides multiple benefits:

• Less room for human error – can be left unattended to run 24/7 if desired. For this method, the user only needs to add salt and sample (15 mL) to the headspace vial – the rest of the process is fully automated.
• Higher reproducibility as the sample prep robot will perform actions consistently for each sample.
• Significantly less sample and solvents are used resulting in a more sustainable approach.
• Lower costs and higher throughput.

Sample Extraction Steps

• ISTD Spiking: Using a dedicated (for ISTD) liquid tool with a 10 µL syringe, 2 µL of ISTD (from a 2 mL autosampler vial) were pipetted into 20 mL headspace (HS) vials containing sample/standards. 
• Solvent Addition: 2 mL of 90:10 isooctane:ethyl acetate solvent was added to the sample vial (20 mL HS) 
• Extraction: The vial was then transported to the vortex mixer and then vortexed at 2,000 rpm for 60 seconds 
• Sample Injection: Using a dedicated (for sample extracts) liquid tool with a 10 µL syringe, 1 µL of analyte protectants and then 8 µL of sample extract were injected onto the 8890/7010 Series GC/TQ

Conclusions

• Excellent sensitivity for OCP’s ( < 0.01 ug/L) was achieved with only 15ml of water taken. 
• The extraction has been shown to be reproducible and robust requiring limited analyst supervision. 
• The automation is embedded within MassHunter requiring no additional software for the control and sequencing of the analysis. 
• The incorporation of mid-column backflush has resulted in consistent responses and retention times throughout the sequences and has minimized contamination of the MS source. The additional JetClean option has resulted in no manual source cleaning being required to date. 
• The automation has been configured to enable minimal analyst interaction by the incorporation of a diluter/dispenser into a large 2.5 L solvent bottle. This way non-mixed solvents can be used together with a fast wash station that means that no contamination will result from waste solvents.

2. Shimadzu: Analysis of THC Metabolites in Urine by GC-MS/MS

• Application note
• Full PDF for download

User Benefits

• MRM in GC-MS/MS uses two-stage mass filtering which allows for the detection of THC and its metabolites without interference from impurities in urine.
• Using MRM creates a method sensitive enough to detect THC and its metabolites in urine at 1 ng/mL that can be used to quantify trace levels of cannabis metabolites in urine.

Cannabis is a long-abused drug with pharmacological effects that include hallucinations, pain relief, and sedation. While the main psychoactive component of cannabis, delta-9- tetrahydrocannabinol (Δ9-THC), issubject to restrictions in many countries worldwide, another active component called cannabidiol (CBD) is not regulated in many countries. Cannabidiol has no major side effects and is starting to be used as a seizure medication, in cosmetics, and in foods. Restrictions on cannabis are undergoing continuous reforms with some countries tightening restrictions and others relaxing them. Japan has recently revised its laws to tighten regulations on cannabis use and a portion of these laws went into effect in December 2024. Δ9-THC in cannabis is metabolized in the body and principally excreted in urine and feces as the metabolites Δ9-OH-THC, Δ9‐THC-COOH, and their glucuronide conjugates. ¹⁾ Based on this, urine must be analyzed for these metabolites to prove cannabis use. This Application News investigated four methods of sample pretreatment that could be used to measure THC and its metabolites in urine and presents results obtained using the sample pretreatment method selected by this investigation in a quantitative analysis by GC-MS/MS (GCMS-TQ 8040 NX Triple Quadrupole Gas Chromatograph Mass Spectrometer).

Conclusions

This Application News investigated the simultaneous analysis of cannabis constituents Δ8-THC and Δ9-THC, and their metabolites Δ8-OH-THC, Δ9-OH-THC, Δ8-THC-COOH, and Δ9‐THC-COOH in urine. Four different extraction methods were tested for the sample pretreatment step. A liquid-liquid extraction method provided the best recovery among the four extraction methods tested and the optimized sample pretreatment workflow resulted in an analytical method with adequate sensitivity and quantitative accuracy. GC-MS/MS was used to create a method sensitive enough to readily detect target compounds at 1 ng/mL in urine that is suitable for the quantitative analysis of trace amounts of cannabis metabolitesin urine.

3. Thermo Fisher Scientific: Non-targeted analysis of whisky using SPME Arrow and Orbitrap Exploris GC 240 mass spectrometer 

• Application note
• Full PDF for download

Whisky is a premium alcoholic beverage based on the tradition built into its production. It consists of a cereal-water mixture or “mash”, which undergoes fermentation followed by distillation and cask maturation, creating a unique flavor profile over a long and complex aging process. Depending on the grain used, cask condition (new vs. old, charred vs. uncharred) and distillery process, significant variability in a whisky's chemical composition can occur. As a result of these distinguishing features, whisky is a sought-after commodity both for consumption and economic purposes, where investments in whisky have far outperformed stocks and other commodities such as gold in recent years.

In this study, the performance of the Orbitrap Exploris GC 240 high resolution accurate mass (HRAM) mass spectrometer together with the headspace solid phase micro extraction (HS-SPME) for chemical profiling of whisky is demonstrated. With high mass accuracy (<1ppm) and resolution capabilities (up to 240,000 mass resolution full width half maximum (FWHM) at m/z 200), the Orbitrap Exploris GC 240 mass spectrometer provides unsurpassed selectivity towards compound identification. Differences in chemical profiles are easily visualized using the statistical tools incorporated into the Thermo Scientific™ Compound Discoverer™ software and a streamlined identification achieved using the Thermo Scientific Flavor and Fragrances HRAM library together with the NIST nominal mass library. Switching between electron impact (EI) and positive chemical ionization (PCI) for molecular ion identification/ confirmation is achieved quickly without system venting using the Thermo Scientific™ NeverVent™ technology. This provides analysts accurate identification of the chemical profile in whisky for product quality control and differentiates between whiskies suspected of fraudulent activities (e.g., additives and mislabeling).

Experimental conditions 

Instrument and method setup 

Headspace extraction and injection of whisky samples was performed using the Thermo Scientific™ TriPlus™ RSH SMART autosampler equipped with the SMART SPME Arrow 1.1 mm DVB/C-WR/PDMS fiber (P/N 36SA11T3-SM). Incubation and extraction were performed online followed by sample injection/ desorption. After sample injection, the SPME Arrow fiber was re-conditioned at high temperature under nitrogen using a SPME conditioning station to avoid sample carryover between injections. Further details surrounding the SPME Arrow operating parameters can be found in Table 1. A Thermo Scientific™ TRACE™ 1610 GC equipped with a Thermo Scientific™ TraceGOLD™ TG-624SilMS (30 m × 0.25 mm i.d. × 1.4 µm film) capillary column (P/N 26085-3320) was used to perform the chromatographic separation. Oven program conditions can be found in Table 1. Data acquisition was carried out in full scan analysis using both EI and PCI with the Orbitrap Exploris GC 240 mass spectrometer. Additional MS method parameters are summarized in Tables 2 and 3. External mass calibration was performed prior to analysis, while characteristic ions representing column bleed were used as lock masses when scanning in EI to perform internal mass calibration. Sample acquisition and qualitative processing were performed using Thermo Scientific™ Chromeleon™ version 7.3.2 Chromatography Data System (CDS) software. Unknown analysis and identification were performed using Compound Discoverer version 3.3 software.

Conclusion

The complex and versatile chemical profile existing among the various whisky types causes challenges in identifying genuine and fraudulent whiskies. Targeted analytical approaches can be applied but cannot provide a complete picture of the chemical composition, potentially missing fraudulent clues. The combination of HS-SPME Arrow with Orbitrap Exploris GC HRAM capabilities provides rapid analysis of both targeted and untargeted compounds giving the following advantages: 

• Time savings with minimal sample preparation and online extraction using the TriPlus RSH SMART robotic autosampler 
• Full scan acquisition at high mass resolution (i.e., 120 000 at m/z 200) providing targeted quantitative analysis with nontargeted chemical profile determination 
• Dedicated Flavor and Fragrances HRAM library enabling accurate identification at sub ppm mass accuracy 
• Mass spectral deconvolution combined with statistical tools for sample differentiation all combined within Compound Discover software