Author: Dragan Krsta

At ADKL Labs a recent project was centred around emerging Persistent Organic Pollutants (POPs). Exposure to POPs can lead to serious health effects and the analysis and monitoring of such substances is critical to ensuring a safe environment for us all. We found the topic very interesting and eye opening. Below we have some background information on this project focused on short-chain chlorinated paraffins (SCCPs).

In the past, SCCPs were mostly used as coolants in metalwork fluids, lubricants and polyvinyl chloride (PVC) processing systems. However, SCCPs are commonly found in many other products, including plasticizers and flame retardants in paints, adhesives, polymers, sealants and textiles. 

Health and environmental impacts of SCCPs was recognised with their inclusion into the Stockholm Convention in 2017. The Stockholm Convention on Persistent Organic Pollutants (POPs) is a global treaty aiming to preserve human and environmental health from persistent chemical contaminants. SCCPs have demonstrated persistence, wide environmental mobility, bioaccumulation, biological toxicity and potential for carcinogenicity. 
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The most commonly applied technique for analysis of SCCPs in water, sediment, sludge and other matrixes remains gas chromatography-mass spectrometry with electron capture negative ionization (GC-ECNI-MS). Three standard methods have been published (listed below) in an effort to harmonize the international approach to SCCPs. The future of SCCP and chlorinated paraffin (e.g., medium and long chain chlorinated paraffins) analysis more widely is towards comprehensive gas chromatography techniques (GC × GC). 

International Standards Organization (ISO) methods:
1.  ISO 12010:2019 — Determination of short-chain polychlorinated alkanes (SCCP) in water — Method using gas chromatography-mass spectrometry (GC-MS) and negative-ion chemical ionization (NCI)
2.  ISO 18635:2016 — Determination of short-chain polychlorinated alkanes (SCCPs) in sediment, sewage sludge and suspended (particulate) matter — Method using gas chromatography-mass spectrometry (GC-MS) and electron capture negative ionization (ECNI)
3.  ISO 18219:2015 — Determination of chlorinated hydrocarbons in leather — Chromatographic method for short-chain chlorinated paraffins (SCCP)

Employing comprehensive gas chromatography enables the user to qualitatively identify groups of chlorinated paraffins by carbon chain length as well as chlorination level. Unfortunately, the processing and interpretation of such data becomes significantly more difficult to execute in a production environment. On the other hand, high resolution mass spectrometry, coupled with improved sample clean-up and better mathematical tools (e.g., multiple linear regression, PCA) can streamline the data interpretation and analysis. While this technology is more widely available than ever, costs related to hardware and expertise remain prohibitive. Analysis of SCCPs remains a difficult task. 

The trend towards increased qualitative and quantitative analysis techniques aligns with the desire of governing bodies to perform informed risk management, source identification and prepare specific remediation plans. The implementation of comprehensive, multidimensional chromatography techniques is not a trivial exercise for any application. The process is particularly complicated for a production (routine) or testing lab where inhouse R&D can be very difficult to execute. ADKL Labs offers carefully tailored advice to ensure successful implementation of any project, focused on three key areas:

1.  Preserving budgets
2.  Upholding timelines 
3.  Building confident users 

Partnering with ADKL Labs ensures the project scope and outcomes are precisely matched to a configuration of hardware, software and user expertise. Confidence in the system robustness and performance is combined with a trained, confident user to maintain performance. 

Please contact ADKL Labs​ if you would like to find out more about our method development and consulting services, as well as our training workshops. 

Note: The views and opinions expressed herein are those of the author and do not necessarily reflect the official position of ADKL Labs.

Author: Dragan Krsta

During a recent Introduction to Gas Chromatography workshop at ADKL Labs the topic of sample discrimination came up. Many factors combine to impact sample discrimination and a thorough understanding of the sample and chromatography system are required to address the issue. The workshop concluded with a wonderful set of example data to demonstrate inlet discrimination, which we've shared below. 

Most users will be familiar with a version of discrimination. For example, volatile components might be introduced onto the column at a different rate compared to high-boilers. Where there is discrimination it can be hard to quantify (or even see) some components within a sample mixture even though you know they are present. You may miss components completely if they do not make their way onto the column after introduction into the GC inlet. The best way to minimize discrimination is to perform on-column injection. However, this technique presents its own practical limitations and also introduces a lot of non-volatile components onto the column. The vast majority of laboratories stick with the proven, robust vaporizing split/splitless inlet. 

In order to demonstrate inlet discrimination during a recent workshop we performed a series of splitless injections using a typical hydrocarbon series. The workshop participants initially struggled to grasp the affect of discrimination. We acquired the below example data while discussing the different parameters and their contribution(s) to sample discrimination. 

All parameters were the same for each injection, except the inlet temperature which was varied from 200-300 ⁰C. You can see a comparison of the chromatograms from this experiment below. There is a lack of late-eluting, high-boiling components within the hydrocarbon series when the inlet is at 200 ⁰C (last eluting peak is n-Tetracontane, C40). However, as the temperature of the inlet increases the peak intensity of the high-boiling components increases. In this scenario, the inlet temperature is likely to be causing discrimination of high-boilers by incomplete elution from the needle and also the inlet liner itself.

Adjusting the inlet temperature can help to reduce discrimination in this case, but other factors should also be considered including potential for thermal degradation of other components, inlet pressure, inlet liner design, liner transit time, column position, needle position, injection speed and more. In this recent workshop discrimination had previously been a problem for the attendees and we tailored the content accordingly.

We hope you found this short example helpful, please contact ADKL Labs with any feedback. 

​Please contact ADKL Labs if you would like to find out more about our training workshops. You can also visit the training page to learn more. We have training workshops from novice to advanced, as well as custom application and method development services.  

Note: The views and opinions expressed herein are those of the author and do not necessarily reflect the official position of ADKL Labs.

Author: Dragan Krsta

The days of “in-house” methods are long gone, or are they? Depending on where you are in the world the need for accreditation often limits the analyses your laboratory can perform. But in most cases the design, development and validation of methods is left to the laboratory performing them. Only the data and quality systems are accredited. Therefore, we see laboratories carry forward legacy methods and procedures, developed many years ago on superseded equipment. Avoiding regular exercises in method development limits accessible efficiency gains. Therefore, at ADKL Labs we develop training packages focused on continuous improvement principles. 

The ADKL Labs team is pleased to announce that we have secured a new location! We are very happy with the new facility and encourage anyone interested in working with the team to contact us to organise a visit!

ADKL Labs is pleased to announce the expanded capabilities within our team. After extensive research the team has expanded internal capacity and capability through the introduction of accurate mass spectrometry to our inventory of analytical equipment. Through the use of high-resolution accurate mass spectrometry we are enhancing our ability to perform accurate impurity analysis followed by deconvolution and library matching.

We are pleased to welcome you to our new website at ADKL Labs.
Over the coming months we aim to grow the content, services and ultimately company.
​The entire team is looking forward to the challenges ahead!