APPLICATIONS

Background : The need for accurate detection of formaldehyde in consumer goods due to its widespread presence and potential toxicity is addressed. This note presents an automated HPLC method with post-column derivatization for sensitive formaldehyde analysis. The automation is carried out using a single vendor system, simplifying the analytical process.  

Problem : Formaldehyde is found in various products, including construction materials, healthcare items, and cosmetics. Short-term exposure to low levels is natural, but high levels and long-term exposure can cause health issues. Chromatographic analysis using GC and LC methods requires derivatization, risking contamination and false positives. 

Approach : The method employs LC separation for non-derivatized formaldehyde, followed by post-column derivatization for sensitive UV or FLD detection. Automation eliminates manual preparation, reducing risks and costs. An Agilent 1260 Infinity II LC system is used, ensuring a streamlined process without third-party add-ons. 

Outcome : The automated LC analysis with post-column derivatization allows precise formaldehyde determination using a single vendor system. The technique provides excellent linearity (0.4-40 µg/mL) with correlation coefficient above 0.999. Injection precision at 10 µg/mL shows low RSD (<2% for repeatability). The Limit of Detection (LOD) is <0.5 µg/mL, surpassing industry standards. Analysis completes in under 15 minutes, maintaining efficiency and accuracy. 

Background : The ISO 9377-2 international standard specifies a method for the determination of the hydrocarbon oil index in waters by means of gas chromatography. Different types of water samples, i.e. drinking, surface, wastewater and water from sewage treatment plants are covered here and an LOQ of 100 µg/L (ppb) is required.

Problem : The ISO 9377-2 described method is a huge challenge for many routine labs. This high throughput method, based on a classical liquid/liquid extraction procedure (LLE) still struggles with high background contamination (high blank levels), risk of reagent, consumable and cross-contamination together with high solvent consumption (not “green”). The labor-intensive sample preparation procedure needs to be followed by a non-discriminating GC injection of the final sample aliquots obtained.

Approach : The mineral oil content is quantified against an external standard mineral oil or a mineral oil within a specific range. A fully automated, miniaturized procedure is used, water samples are extracted by hexane and sample clean-up is performed with Florisil to remove polar components present in the water. Avoiding an evaporation step and miniaturizing the sample preparation requires the use of a large volume injection technique to reach the LOQ of 0.1 mg/L without introducing discrimination. Purified sample extracts are injected into the GC using an Early Vapor Exit (EVE) – COC injection system. A chromatogram is measured using a non-polar column and universal non-selective FID detection. The total peak area between C10 and C40 is integrated and used for quantification of the total mineral oil content.

Outcome : A fully automated mineral oil analyzer was optimized, resulting in full automation of the sample preparation, sample prep miniaturization and high-throughput analysis. An Early Vapor Exit (EVE) – COC injection system can be used to vent-off high amounts of injected sample extracts (100 µL) without discrimination and finally making it possible to reach the LOQ of 100 µg/L (ppb).

Background : Food and beverage industry requires accurate aroma profiling to deliver final products with correctly dosed key flavor compounds. They also need to pick up any unwanted off-flavor compounds to ensure product quality is not compromised.

Problem : Small concentration variations in key aroma compounds and ultra-trace levels off-flavor compounds can drastically affect final product quality, while the robustness of the analysis is significantly impacted by the applied sample preparation techniques as well as the type of mass spectrometric detector used.

Approach : We start with dynamic headspace (DHS) sampling which is the most exhaustive headspace sampling technique for gas, liquid, and solid samples. Sample separation is achieved using capillary gas chromatography (GC) coupled to a time-of-flight (TOF) mass analyzer. The latter will extend the range of detectable aroma compounds due to its high sensitivity in full scan mode. This setup here also allows for untargeted screenings. It comes with spectral continuity and increased acquisition speed allowing the deconvolution of aroma compounds that chromatographically coelute.

Outcome : A reliable configuration capable of monitoring the lowest levels of variation in key aroma compounds together with potentially impacting off-flavors. This setup can easily be installed in R&D and QC labs to perform quality control of raw materials and finished products, shelf-life/aging studies, product development as well as general troubleshooting.

Background : Fats and oils are mainly composed of triglycerides and contain saturated, mono-unsaturated, and poly-unsaturated fatty acids. Routine analysis is performed by monitoring fatty acid methyl esters (FAMEs) that originate from triglycerides. These FAMEs are a key attribute for evaluating the overall quality of fats and oils in the food industry. Unsaturated fatty acids are known to have the cis-configuration, however industrial processes can cause partial isomerization to trans-configuration. As these are linked to unhealthy nutrition, it is important to be able to trace in both a qualitative and quantitative manner.

Problem : The Association of Official Agriculture Chemists (AOAC International) has released several testing procedures for FAMEs using capillary gas chromatography. However, these methods are not straightforward and require several steps: acid or alkaline hydrolysis of the glycerides, derivatization into methyl esters and extraction of the FAMEs with an apolar solvent. For a manual procedure these sample preparation steps are time consuming and labor intensive. The assay is also prone to artefacts and is considered environmentally unfriendly due to the need of large amounts of solvents and reagents.

Approach : We introduce automation to these established procedures to eliminate the disadvantages of manual steps. For this we use the GERSTEL MPS (MultiPurpose Sampler) which is able to perform all official AOAC methods and can also handle sample injection and prior to GC analysis in an automated manner.

Outcome : A configuration that will boost productivity with fully automated 24/7 runs, improve reproducibility and deliver results in a eco-friendly way. This setup can easily be installed in R&D and QC labs to perform quality control of raw materials, finished products as well as product development.

Background : Fatty acids are essential molecules in biological systems and have been shown to act as biomarkers for multiple diseases. Understanding how fatty acids behave in different cells, vesicles or tissues can therefore provide valuable insights in disease triggers and help create new therapies. Short chain fatty acids (SCFAs) present in biological samples can be directly measured following solid phase microextraction (SPME). Longer chain fatty acids, which can be present as free fatty acids or bound in lipids, first need to be subjected to derivatization (mainly via acid or alkaline methylation) forming fatty acid methyl esters (FAMEs) prior to liquid injection.

Problem : The separation of SCFAs and FAMEs is done by gas chromatography (GC) using two dedicated columns. Furthermore, each compound class requires a different mode of detection: FAMEs are picked up by flame ionization detection (FID) whereas SCFAs are monitored through mass spectrometry (MS). Transitioning from one analysis mode to another requires operator intervention and leads to significant downtime.

Approach : For our sample preparation and sample introduction we rely on a GERSTEL MPS (MultiPurpose Sampler) which is able to handle both protocols. A dedicated GC configuration equipped with Capillary Flow Technology (CFT) with two inlets which fully automates the switch between SCFAs and FAMEs testing.

Outcome : A configuration that will significantly reduce operator workload as well as system downtime hereby improving productivity. This setup can easily be installed in R&D labs to perform in-depth analysis of various biological samples.

Background : During the refining step of edible oils and fats several well-known process contaminants can be formed, more specifically 3-monochloropropane-1,2-diol (3-MCPD), 2-monochloropropane-1,3-diol (2-MCPD) and glycidol under the form of esters of different fatty acids. For health reasons it is important to monitor human exposure to these contaminants. Accurate quantification of these compounds in edible oils and fats is crucial. Analysis can be performed indirectly according to established AOCS methods and more recently according to the Zwagerman-Overman method. The latter is gaining popularity because it allows fast analysis of all 3 contaminants in a single run.

Problem : Manual sample preparation as part of the analysis is labor intensive and reaction times are critical for accurate quantification of glycidol and to obtain adequate reproducibility. This leaves the method highly susceptible to human error while the used reagents are also harmful.

Approach : Our automated setup, including preparation of calibration and recovery samples, uses the GERSTEL MPS (MultiPurpose Sampler) and is based on fast alkaline transesterification. An additional automated evaporation step allows for the efficient removal of excess derivatizing agent. Analysis of phenyl boronic derivates is performed via gas chromatography coupled to tandem mass spectrometry (GC-MS/MS). An additional automated evaporation step allows for the efficient removal of excess derivatizing agent. An additional automated evaporation step allows for the efficient removal of excess derivatizing agent.

Outcome : A configuration that will deliver results in an extremely robust manner with only one manual step: placing the vial in the autosampler prior to analysis. It also offers the possibility of changing your sequence last-minute and adding samples at any time depending on urgency. As an added benefit, reduced amounts of derivatizing agents reduce the need for source clean-up or column/pre-column exchange which translated into significantly less downtime. This setup can easily be installed in QC labs product release.