News from LabRulezGCMS Library - Week 53, 2025

Our Library never stops expanding. What are the most recent contributions to LabRulezGCMS Library in the week of 29th December 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 application notes by Agilent Technologies and Shimadzu!

1. Agilent Technologies: Fatty Acid Methyl Ester Analysis Using the Agilent 8850 GC System

• Application note
• Full PDF for download

Fatty acids are components of fat and are an essential component of a healthy diet. They are found in a variety of foods, including oily fish, nuts, seeds, and vegetable oils. Fatty acids can be categorized as saturated fat, monounsaturated fat, polyunsaturated fat (including omega-3 and omega-6 fatty acids), and trans fat. Unsaturated fatty acids play a beneficial role in maintaining heart and vascular performance. However, artificial trans fatty acids, found in processed foods, should be strictly limited. The measurement of fatty acids in food plays an important role in:

• Nutritional assessment: Analyzing the omega-3/omega-6 ratio for dietary nutrient balance 
• Safety regulation: Identifying health risks such as trans fatty acids 
• Quality control: Detecting oil adulteration and process defects 
• R&D support: Providing data support for the development of functional foods 

Techniques available for fatty acid determination in food include gas chromatography, liquid chromatography, and spectroscopic techniques. Each technique has its own advantages, disadvantages, and applicable scenarios. For example, liquid chromatography is suitable for analyzing heat-labile fatty acids, but it suffers from low resolution. Fluorescence spectroscopy is simple to operate but susceptible to matrix effects and poor specificity. Gas chromatography is the most used technique for fatty acid measurement. Fatty acids in food primarily exist in the form of triglycerides. Before analysis, triglycerides must be extracted, saponified, and methylated to the corresponding FAMEs. FAMEs are less polar and more volatile than fatty acids, making them suitable for analysis on gas chromatography platforms. Polar columns, such as those with polyethylene glycol and cyanopropyl siloxane stationary phases, are primarily used for the FAMEs analysis. Polyethylene glycol stationary phases are good at analyzing simple fatty acid mixtures and are not suitable for the analysis of cis-trans isomers. A column coated with high‑content cyanopropyl phase is recommended in different analytical methods for FAMEs analysis. However, an analysis based on this phase type usually takes more than 70 minutes to finish, and the retention time (RT) stability is not very good. The Agilent J&W DB-FastFAME column features a modified cyanopropyl phase to accelerate the analysis and improve repeatability. 

Agilent offers DB-FastFAME columns in different dimensions; the 20-meter and 30-meter sizes can help improve the analysis speed for 37 representative FAMEs in food. Previous work demonstrated the analysis speed improvement using the conventional oven ramp rate on the two columns.¹ With the launch of the Agilent 8850 GC, rapid temperature programming can be achieved in an air bath oven. This application note demonstrates the fast analysis of 37 FAMEs using nitrogen (N2 ) and helium (He) carrier gases on the 8850 GC. Meanwhile, more complex FAME mixtures including 37 FAMEs and 15 trans FAMEs were analyzed on a 90-meter DB-FastFAME column and a 100-meter Agilent J&W HP-88 column to demonstrate the 8850 GC performance in cis/trans FAMEs and position isomers analysis.

Experimental

Instrumentation 

An 8850 GC system equipped with a split/splitless inlet and a flame ionization detector (FID) was used for the analysis. An Agilent 7650A automatic liquid sampler (ALS) (part number G4567A) was applied for sample injection. 

The methods performed on the four analytical columns using He and N2 carrier gases are listed in Table 1. The settings on inlet and detector temperatures are the same. The column head pressure and the oven temperature program were optimized based on the column type and carrier gas. Data were acquired and processed using Agilent OpenLab CDS 2.8. The list of consumables used is shown in Table 2.

Results and discussion 

Fast analysis of 37 fatty acid methyl esters on short columns 

The 37 FAMEs mimic the fatty acid composition of many food samples, including most of the important saturated, monounsaturated, and polyunsaturated FAMEs. They are well‑established and widely accepted reference materials. 

A 20 m × 0.18 mm id, 0.2 µm DB-FastFAME column and a 30 m × 0.25 mm id, 0.25 µm DB-FastFAME column were used to demonstrate the high-speed analysis of 37 FAMEs on the 8850 GC. The oven ramp program and column flow rate were based on previous work and further optimized for the 8850 GC. Both He and N2 carrier gas-based methods were developed considering the increasing alternative carrier gas need and lab operation habits in different regions. 

The GC-FID chromatograms obtained on the two columns using different carrier gases are shown in Figures 1A, 1B, 2A, and 2B. All compounds were well resolved in the He methods. Three compound pairs that cannot be baseline-separated are shown in black squares. Among them, the peaks of c22:2n6 and c23:0 had the lowest resolution of 1.27 and 1.31 on the 20-meter and 30-meter columns, respectively, using the He method. The AOAC International Method 996.062 requires separating the FAME pair of adjacent peaks of C18:3 and C20:1 and the FAME trio of adjacent peaks of C22:1, C20:3, and C20:4 with a resolution of 1.0 or greater. This requirement is mainly recommended for high-content cyanopropyl 4 stationary phases. The six probe FAMEs eluted in different orders on the DB-FastFAME column, as marked by the yellow squares in the chromatogram. Their separation exceeded the resolution requirement easily due to the DB-FastFAME column's unique selectivity. The analysis times of the He methods were less than 7 minutes and 10 minutes on the two columns. The analysis speed was five to eight times faster than that of conventional methods.

Conclusion 

A high-speed FAMEs analysis was achieved on an Agilent 8850 GC system with excellent repeatability when running the FAMEs standards on specially engineered 20-meter and 30-meter Agilent J&W DB-FastFAME columns under optimized oven programs. The analysis time is less than 10 minutes using He carrier gas and less than 15 minutes using N2 carrier gas, which is five to eight times faster than the conventional method. Peak resolutions obtained by the fast methods met the AOAC 996.06 standard requirements. The methods can help improve lab productivity significantly for routine analysis of 37 FAMEs. 

The analysis of 52 FAMEs on 90-meter DB-FastFAME and 100-meter Agilent J&W HP-88 columns demonstrated that the 8850 GC can deliver performance equivalent to the Agilent 8890 GC system when analyzing complex fatty acids—including cis/trans fatty acids and positional isomers— in terms of resolution, area repeatability (< 2.5%), and RT precision (< 0.04%).

2. Shimadzu: Quantification of 8 Disinfection Byproducts from Water by Liquid-Liquid Extraction and Gas Chromatography-MassSpectrometry

• Application note
• Full PDF for download

Disinfectants such as chlorine and chloramine are widely used to eliminate microorganisms in water. However, these disinfectants react with naturally occurring chemical constituents, such as amino acids and other labile organic chemicals, forming a range of disinfection byproducts (DBPs). Chronic exposure to DBPs elevates the risk of developing cancer, liver damage, and decreased nervous system activity. Hence, accurate detection and quantification of DBPs in water is crucial. 

Although official recommended method for measuring DBPs is based on GC/ECD, GC/MS offers significant advantages in terms of simultaneous quantification and identification of both known and unknown compounds in a single analysis, providing comprehensive data on complex water samples. Unlike ECD, which has a limited dynamic range and can only detect electroactive compounds, MS offers a broader dynamic range, allowing the detection of analytes at varying concentrations. Additionally, GC/MS provides superior sensitivity, specificity, and structural information, making it the ideal method for detailed, high-precision analysis of disinfection byproducts and other water contaminants.

2.2. Analytical Conditions

Preparation of instrument and analysis:

The analytical method was established, and the instrument parameters are detailed in Table 1. Prior to the analysis, both the instrument and the column were conditioned. The “HighSensitivity” autotune mode of the GCMS-QP2020 NX was used for the analysis. A standard solution containing 500 ppb of the target analytes, surrogate, and internal standard was injected using the MS fullscan mode to determine the retention times.

The peaks corresponding to the target compounds, internal standard, and surrogate were identified using the NIST GC/MS library. Quantifier and qualifier ions for each analyte were selected, and a compound table was created accordingly and the same was used to develop a Scan/SIM method using the “Creation of Automatic Scan/SIM Table” (COAST) wizard within the GCMSsolutionTM software. The ultra-fast scanning capability (20,000 u/s) of the GCMS-QP2020 NX enables simultaneous acquisition of Scan and SIM events without compromising data quality. 

The newly created Scan/SIM method was used for the quantification and reporting of analytical data. Calibration standards were analyzed. The data and the calibration curve, using the internal standard method, were processed using LabSolutions InsightTM software which enables the analysis of large numbers of data simultaneously. Following this, both the unspiked and spiked (5 ppb) samples were analyzed and quantified.

3. Result and Discussion

A 6-point calibration curve was created for all target analytes. A good linear response, with correlation coefficients (r²) greater than 0.99, and accuracy within 80-120% was observed for all analytes. A signal-to-noise ratio (S/N) ≥ 10 was observed for all analytes at 5 ppb standard. The results are shown in Table 2.

4. Conclusion

• A highly sensitive GC/MS method was developed for 8 halogenated DBPs using Shimadzu GCMS-QP2020 NX following USEPA 551.1 sample preparation protocol. 
• Excellent linearity results and recovery results at 5.0 ppb concentration for all the analytes demonstrate that the analytical workflow is suitable for analyzing the listed DBPs in tap water using GC/MS technique at a low concentration level.