News from LabRulezGCMS Library - Week 10, 2025

Our Library never stops expanding. What are the most recent contributions to LabRulezGCMS Library in the week of 3rd March 2025? Check out new documents from the field of the gas phase, especially GC and GC/MS techniques!

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👉 Need info about different analytical techniques? Peek into LabRulezLCMS or LabRulezICPMS libraries.

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

1. Agilent Technologies: GC/MS Approach for Analysis of
Extractables and Leachables (E&L) in Complex Matrices Using Spectral Deconvolution and Retention Indices

• Poster
• Full PDF for download

Modern drug delivery systems are meant to protect a drug from environmental contamination, but they may also be a source of contamination. It is necessary to identify those compounds that can extract, leach, or migrate from the package or device. Extractables and leachables analysis presents a challenge for GC/MS because of the complexity of the various sample matrices and a diverse range of compounds to be identified. This study demonstrates how unit resolution GC/MS workflow is employed for identifying GC-amenable E&L compounds by leveraging spectral deconvolution in combination with retention index-based time filtering. An addition of the accurate mass high-resolution GC/Q-TOF into the workflow provided extra confidence in compound identification, sensitivity and capability of structural elucidation. 

Operating in the OpenLab Electronic Content Management (ECM) XT configuration enabled tools that help facilitate compliance with various national and EU electronic record regulations, including audit trails, and remote data storage.

Experimental

Rubber syringe gaskets were extracted using tetrahydrofuran (THF) solvent at room temperature for six months. An aliquot of the extracts was analyzed using both GC/MSD and GC/Q-TOF systems. The acquisition software operated under a unified compliance environment. The instrumental parameters are shown in Table 1. The chromatographic deconvolution and library search were performed in the MassHunter Unknowns Analysis 12.1. The NIST23 library was used to perform initial compound identification. Structural elucidation was performed using Molecular Structure Correlator (MSC) software 8.2. 

Retention time locking was used to achieve the same retention times between multiple GC/MSD and GC/Q-TOF systems allowing for using both retention index and retention time matching.

Conclusions

• The optimized GC/MSD and GC/Q-TOF approach for analysis of extractables and leachables allowed for identifying over 150 compounds in a complex E&L extract 
• High-resolution GC/MS enabled identification of over 60 additional components with increased confidence and structure elucidation of the unknowns 
• The novel ultra low bleed Agilent J&W DB-5Q GC column resulted in significant decrease in background, that could potentially yield higher number of identifications of late eluting compounds.

2. Knauer: GPC cleanup method for soil samples before PAHs analysis

• Application note
• Full PDF for download

GPC (Gel Permeation Chromatography) is a size-exclusion clean-up procedure that readily separates high molecular weight interferents from sample extracts using organic solvents and a porous hydrophobic gel (primarily a crosslinked divinylbenzene-styrene copolymer) [1]. It is possible to distinguish between different types of Bio-Beads resin based on the type of cross-linkage. In this application Bio-Beads S-X3 with 200–400 mesh was used according to EPA method 3640 [1]. GPC clean-up can be used extensively in numerous environmental analysis especially for preparing sample extracts prior to semivolatile compounds determination, such as pesticide, and PAHs analysis by GC/MS or HPLC-UV-DAD. Sample cleanup is particularly important for analytical separations such as GC, HPLC, and electrophoresis because high-boiling materials can cause a variety of problems in analytical systems, like analyte adsorption in the injection port or in front of a GC or LC column [2]. GPC cleanup protects GC and HPLC columns, reduces analytical maintenance costs, improves accuracy, and allows lower detection limits.

Materials and Methods

Extraction of Polycyclic Aromatic Hydrocarbons was carried out using Accelerated Solvent Extraction (ASE), according to the 3545A EPA method [3]. Bio-Beads S-X are supplied dry and must be swollen prior to pack into a chromatographic column. A mixture of cyclohexane and dichloromethane (70:30, v:v) is suitable for clean-up of soil samples. As a general rule, the beads should be swollen in the same solvent chosen as mobile phase, so 10 g of Bio-Beads S-X3 were swelled with 50 mL of cyclohexane and dichloromethane mixture (70:30, v:v) overnight. After the beads were fully swollen, they were packed into a chromatographic column. Before sample cleanup, GPC column was equilibrated with the desired solvent mixture, flushing it almost three times the column volume at 1 mL/min. Cleanup method was performed with AZURA® GPC Cleanup System, which is operated with the Mobile Control Chrom® Software running on a tablet directly mounted on the system. The identification and quantification of PAHs was carried out by GC-MS/MS analysis. Calibration curves were constructed in the concentration range from 10 μg/L to 130 μg/L. To perform GC separation and MRM acquisition, optimization of the best chromatographic and detection conditions was necessary.

Conclusion

This application shows how to perform GPC cleanup with KNAUER AZURA® GPC Cleanup System for the analysis of PAHs in soil samples. This report is very detailed to ensure good performance in GPC cleanup for application in environmental area. We can conclude that AZURA GPC Cleanup System is an helpful tool for sample preparation before instrumental analysis because, unlike other techniques, is very useful for the removal of high boiling materials which would contaminate injection ports and column heads, prolonging column life, stabilizing the instrument, and reducing column reactivity. It could be considered an universal cleanup technique for a broad range of semivolatile organics and pesticides. Moreover, AZURA GPC Cleanup System allows the customer to process many extracted samples, with a reduction in time for the cleanup procedures.

3. Shimadzu: Blood alcohol content (BAC) analysis using a liquid injection approach

• Application note
• Full PDF for download

User Benefits

• Blood alcohol analysis using liquid injection is an alternative to the headspace
• analysis of blood samples for clinical purposes
• It provides reliable results for whole blood and plasma samples without adverse matrix effects 

Blood alcohol content (BAC) is relevant for legal regulations regarding driving limits, but also investigated for forensic and clinical purposes with respect to poisoning. Blood alcohol analysis does not only focus on ethanol, which is the classical drinking alcohol, but also investigates other alcoholic substances like methanol and isopropanol as well as metabolites like acetone. Ethanol is present in alcoholic beverages, but also used for antiseptics, various daily life products, and pharmaceuticals. Being a central nervous system depressant, consumption can cause severe intoxication with toxic levels at above 100 mg/dL blood [1]. Methanol intoxication could originate from the consumption of counterfeit alcohol, with as few as 30 mL pure methanol consumed being potentially lethal [2]. Isopropanol is widely used as solvent or antiseptic in households and sometimes used as cheap substitute for ethanol by alcohol abusers. It is metabolized by alcohol dehydrogenase to acetone, which alike isopropanol is a central nervous depressant [3].

Blood alcohol analysis can be performed using gas chromatography (GC) with flame-ionization detection (FID). Due to the complexity of blood as matrix, headspace analysis is a widely used technique for simple sample transfer onto the GC column, which is especially valuable in forensics, where the matrix states investigated can drastically vary depending on the time the sample is taken. For clinical analysis, fresh blood is used, making the sample more uniform. In this approach, the analysis of BAC using a liquid injection technique as alternative to headspace sampling is presented.

The Package

The recommended analytical hardware and software configuration is listed below.

• Main Unit
  • Nexis GC-2030 with FID-2030: Gas chromatograph with flame ionization detector
• Accessory
  • AOC-30i autosampler: Liquid autosampler with 30 vials capacity
• Main Consumables
  • SH-BAC1 column (30 m x 0.32 mm x 1.8 µm;
  • P/N 221-76135-30)
• Software
  • LabSolutions LCGC

Conclusion

Liquid sample injection presents a reliable alternative to headspace injection when analyzing blood samples for clinical purposes. Ethanol and methanol can be determined from whole blood, isopropanol and acetone from plasma samples without adverse matrix effects. Both whole blood and plasma analysis can be done using the same analytical method and one data processing approach, facilitating data evaluation and routine work.

4. Thermo Fisher Scientific: Trace analysis of volatile organic compounds in wastewater according to U.S. EPA Method 624.1 

• Application note
• Full PDF for download

It is crucial that analytical testing laboratories monitor wastewater for the presence of volatile organic compounds (VOCs). VOCs are human-made contaminants used and produced in the processing of paints, adhesives, petroleum products, pharmaceuticals, and refrigerants. If they are released into wastewater from industrial activities, they can have an adverse effect on the natural environment and, ultimately, the public.¹ U.S. EPA Method 624.1 is an approved test method under the Clean Water Act² for determination of purgeable organic pollutants in industrial discharges and other environmental samples. The accurate detection and quantitation of VOCs via this method help ensure wastewater is not contaminated. Due to technological advances in analytical instrumentation and techniques, U.S. EPA Method 624.1 allows the analyst to modify P&T parameters and GC/MS conditions. This can result in reduced sample run time and increased laboratory throughput in a 12-hour period. 

To perform U.S. EPA Method 624.1, method acceptance criteria must be achieved. These criteria include creating a working calibration curve, method detection limits (MDLs), and Initial Demonstration of Capability (IDC) of accuracy and precision for target compounds. As the sample matrix is water, it is essential that moisture is reduced, limiting the impact on the analytical column as this could damage the column and affect the results. 

The following evaluation describes the use of the ISQ 7610 GC-MS system coupled with a TRACE 1610 GC equipped with the Thermo Scientific™ HeSaver-H2 Safer™ split/splitless injector and a Teledyne LABS Tekmar Lumin P&T concentrator paired with the AQUATek LVA autosampler for U.S. EPA Method 624.1 for the analysis of wastewater.

Experimental

GC-MS parameters 

A TRACE 1610 GC was coupled to the ISQ 7610 MS equipped with a Thermo Scientific™ NeverVent™ vacuum probe interlock (VPI) and a Thermo Scientific™ ExtractaBrite™ ion source. A Thermo Scientific™ TraceGOLD™ TG-VMS, 30 m × 0.25 mm, 1.4 µm film column (P/N 26080-3320) was used for compound separation. The HeSaver-H2 Safer injector was utilized which reduces the carrier gas consumption by decoupling the gas used for the chromatographic separation from the gas used to pressurize the inlet and maintain split and purge flows. The critical separations were maintained with a run time of under 13 minutes. 

For this analysis, the ISQ 7610 MS was operated in full scan mode, ensuring the sensitivity needed for required the method detection limits. Nevertheless, the instrument could operate in Selected Ion Monitoring (SIM) mode for increased selectivity, if needed. Extended method parameters for the ISQ 7610 MS are shown in Table 2.

Conclusion

The ISQ 7610 MS system with the VPI coupled with the Teledyne LABS Tekmar Lumin P&T concentrator paired with the AQUATek LVA autosampler exceeds all the requirements outlined in U.S. EPA Method 624.1 for analysis of VOCs in wastewater:

• MDLs calculated from n=7 repeat injections of 0.5 ppb water standards showed no interference from unwanted water entering the system and resulted in values <0.15 ppb for most compounds.
• Precision and accuracy for n=7 20 ppb water standards showed excellent results with %RSD <20% and mean recovery of 93% for the compounds.
• System robustness was tested by continuously acquiring 209 injections of water samples over two days with no user intervention at all. The average %RSD of the calculated concentration was 6.5% over this robustness study.
• Utilizing the HeSaver-H2 Safer technology reduced helium consumption for the method by 4 times, reducing laboratory overheads. 

Further information on VOC analysis using the ISQ 7610 system and the Tekmar Lumin P&T paired with the AQUATek LVA can be found in the Thermo Fisher Scientific AppsLab library.³