Chromatographic Analysis – Sample and Standard Preparation

Chromatographic analysis with techniques like HPLC, UHPLC or GC is commonly used in analytical R&D and QC labs to identify, quantify and purify individual components of a mixture. Component purity, concentration and composition have a major influence on final product quality, which can impact product efficiency, safety, shelf-life, and many other important features. To obtain quantitative results, calibration standards or reference substances in known concentrations are needed.

Why weighing is important?

In analytical chromatography, accurate weighing, proper calculation of concentrations and error-free transfer of data have a significant impact on the quality of chromatographic results. Sample preparation can use up to 60% of analytical laboratory time and effort. Moreover, data management such as results transcription and archiving can use up to 25% of working time. Underlying the importance of state-of-the-art process automation and data management: the more tasks that can be automated and simplified without compromising accuracy, the better in terms of conserving resources and enhancing throughput and accuracy.

Chromatography is a technique commonly used in analytical R&D and QC laboratories. Gravimetric preparation of standard solutions is not only more accurate and reliable than preparation by volumetric methods, but also allows a reduction in the quantities required. With automatic dispensing of powders and liquids, standard preparations for HPLC analysis can be further accelerated. The XPR automatic balance makes standard preparation more efficient and accurate with smaller sample volumes. Watch the video to discover how.

1. Identify reference standard
2. Weigh reference standard
3. Add solvent, shake and mix
4. Dilute to prepare suitable concentrations
5. Calculate/record results
6. Label flasks
7. Filtrate and transfer to analysis vials
8. Analysis by variety of analytical techniques:
   • HPLC, GC, NMR
   • ICP-MS, ICP-OES
   • AA, Organic Elemental Analysis
   • Titration, Karl Fisher
9. Data evaluation
10. Result calculation
11. Reporting
12. Secure data storage
13. Data retrieval (for audit)

Gravimetric sample preparation – weighing both the solid and the solvent – is a state-of-the-art approach to preparing samples and solutions that is specifically described in USP chapter 1251 "Weighing on an analytical balance" in the section "Types of dosing" USP36-NF31 (2013). For more information, consult our White Paper “Gravimetric Sample Preparation – Reducing Sample Size and OOS Errors”.

Is chromatographic analysis one of the "time-eaters" in your laboratory? Lay the foundation for your lab of the future and invest in an automated and digitized sample and standard preparation for your chromatographic analyses. Let us show you how the modular elements of our automated solutions – tailored to your specific requirements – can make your chromatography processes more efficient and safer.

Manual volumetric vs. automated gravimetric liquid powder and dispensing

Manually weighing out powdery substances with a spatula can be a tedious and challenging task. Especially when amounts are in the low milligram range, it takes skill and experience to weigh accurately.

Even in the best of hands, traditional solution preparation with volumetric glassware is time-consuming and prone to error. An operator will typically weigh a substance onto weighing paper and then transfer it into an Erlenmeyer flask. Does the operator back weigh the paper to ensure no substance is left behind? If not, doubt is created about process accuracy. If so, extra time is added to the workflow. Neither choice is ideal.

With the amount of laboratory time spent processing standard solutions estimated to be greater than 60%, measures that can reduce such incidences can significantly improve overall accuracy and laboratory productivity.

Data management, transfer and traceability

Data handling and traceability of chromatographic data is laborious and prone to error. For example, a lab technician must be diligent in recording each step of a dataset’s journey when switching among instruments and systems. Especially when a high throughput is necessary and data must be traceable, software-driven workflows and networked systems lead to a modern and highly efficient lab.

Accelerate your processes — apply automation and digitalization strategically

Automation is increasingly employed in laboratories to keep productivity high, reduce results subjectivity, and free scientists for high-value experimentation. The tactical adoption of instruments and software aligned with day-to-day procedures can substantially benefit operations.

Where higher throughput is necessary, laboratories can leverage software-driven workflows that integrate instruments into a network and ensure that complete data is collected and securely recorded for every sample.

Here, we provide an overview of our solutions that can help you automate and digitalize your sample and standard preparation for chromatographic analyses. Which one is right for you based on your current chromatographic analyses and throughput requirements?

Manual weighing processes are time-consuming and labor-intensive, and any mistakes can lead to major errors in downstream processing. Automated weighing addresses these challenges. Our innovative approach to automation saves time and delivers highly reproducible results, giving you the freedom to focus on other critical elements of your analysis.

Reliable analytical results begin with accurate weighing. METTLER TOLEDO's XPR Analytical Balances offer readabilities from 0.002 mg to 0.1 mg and a capacities up to 320 g. With a vast range of proven innovative technologies and advanced quality assurance functions, you can be sure of fast, reliable and valid results every time you weigh.

XPR Analytical Balances enable manual and volumetric workflows by means of manual powder solvent dispensing into a volumetric flask. Investing in a XPR Analytical Balance is an excellent start for future automation and digitization of your sample and standard preparation for chromatographic analyses. Many labs consider automation and digitalization prohibitively expensive. With our modular approach, the latest solutions are affordable.

Choose your level of automation and put together your individual digitalized solution. You can either upgrade your analytical balance for accuracy or opt for a more automation and time savings with the XPR Automatic Balance or robotic solution.

The appropriate software can be used at any level of weighing with an XPR balance. Upgrade your sample and standard preparation process and benefit from:

• Seamless data management
• Fewer steps for greater efficiency
• Smaller volumes/sample sizes, less material needed
• Higher accuracy and reproducibility
• Automation of single or multiple process steps

Connect your XPR Balance to LabX™ Balance Software. LabX enables solution preparation with automatic documentation and data processing. Metadata is automatically captured and saved in a centralized database. LabX guides you step-by-step through your SOP with clear on-screen instructions. All calculations are performed automatically and transcription errors are eliminated.

Watch the video: LabX Software for Accurate HPLC Standard Preparation in Pesticide Residue Testing

Add the LabX - OpenLab Plugin to transfer weighing data and metadata from LabX Balance software to the Agilent OpenLab Chromatography Data System (CDS). This Balance–LC/GC bridge lets you greatly reduce error risk, as it eliminates manual calculations and data transcription for the HPLC analysis process.

By making the switch to gravimetric standard preparation, both solids and solvents are measured by weight, not volume. The user defines the concentration required and the target amount of solution. Then, the system software calculates the target amount of solid to dispense and delivers the appropriate amount of diluent according to the actual amount of solid dispense. This assure an extremely accurate and precise concentration.

Add a QLX3 liquid dispensing module to your XPR Analytical Balance, automate the liquid dispensing step and make the switch to the more accurate gravimetric solution preparation with less material required. This is a simple and inexpensive solution for automated calculation and automated gravimetric dispensing of solvents based on manually weighed solid substances (even non-powders).

Gravimetric standard and sample preparation offers the following benefits:

• Lower minimum weight
• Improved accuracy of prepared solutions and results quality
• Fewer workflow steps, better efficiency and productivity
• Sample is weighed directly into a vial
• Solvent is added accurately based on weight
• Less sample, standard, and solvent is needed and less waste is created
• Reduced risk of overfilling
• No subjective or temperature dependent meniscus reading
• No cleaning of volumetric flasks or pipettes

Upgrade your balance to an XPR Automatic Balance with powder and liquid dispensing modules and benefit from an automated solution for the gravimetric dispensing of powders and solvents. Automatic weighing reduces the minimum weight by up to 30% and enables material savings of up to 70%, giving you an extraordinarily fast return on your investment.

This application note presents a quick and easy way to prepare accurate reference standards for HPLC and other chromatographic methods. The method enables using less substance and solvent, ultimately significantly saving time and money.

Add the QS3 sample changer accessory to your XPR Automatic Balance and upgrade it with a semi-automated vial handling to create a solution with increased throughput for up to 30 target vials.

Fully automate your sample and standard preparing processes with the CHRONECT XPR robotic dispensing system and prepare up to 288 solutions in one run, consisting of up to 32 powders and 6 liquids and enabling many-to-many methods. The unique system combines the advanced weighing and dispensing technology of the XPR Automatic Balance with a state-of-the-art 6-axis robotic arm and the easy-to-use CHRONOS software. Reduce time spent at the bench and attend to more valuable tasks.

Watch the video: fully automated sample and standard preparation with CHRONECT XPR robotic dispensing

CHRONECT XPR features fully automated dispensing of powders and liquids, including robotic vial handling. It offers unprecedented accuracy, repeatability, efficiency, and flexibility. Samples and reference standards for chromatographic analyses can be prepared conveniently overnight, making them ready for next steps in the morning.

Our application note presents a fully automated, robotic process for preparing accurate samples and reference standards for chromatographic analyses like HPLC. The method allows scientists to reduce time spent at the lab bench and attend to more valuable tasks.