Analytical measurement systems bring automation to sample preparation

Analytical determinations are of great importance in various fields such as chemical, pharmaceutical or biotechnological research, tracking of reactions and production processes or quality control of consumer products. The 24/7 full utilization of analytical systems in sequential processes is necessary and important. For this reason, today almost no corresponding instruments are sold without automation technology. Automation mainly exists in the realization of automated sample tasks and/or ensuring sample changes.

Measurement technology preparation for determinations is often required in the sample preparation phase, in order to separate the sample to be measured from accompanying substances or to transport it in a measurable form. There are only a few instruments or instrument systems that can be used with the necessary sample preparation. It is absolutely necessary that if there is sample preparation, it must be carried out online directly before the analysis in order to avoid the decomposition of sample components.

Requirements

Since the costs in sample preparation are different for each different analytical system and subject, the requirements for automated sample preparation are also different. Sample preparation, such as the accurate determination of the dosage of substances or the dilution of solutions, can already be carried out by an ordinary liquid handler. If heavy water concentration, filtration, centrifugation and/or derivatization steps are required, the necessary automation costs for this are also significantly higher. Depending on the implementation, it is also necessary to consider implementation under specialized conditions such as inert conditions (chemical solutions) or sterile conditions (biological, especially cell-based systems).

There are two essential issues for automated system solutions:

a) Sequential vs. simultaneous sample preparation.

The decision on sequential or simultaneous sample preparation depends on the specific reaction requirements. Therefore, the issues of required material throughput, time requirements and the number of preparations to be carried out must be considered. Applications in the clinical, cell or genomic fields can usually be automated relatively easily; or the number of samples is relatively large, for which reason the degree of parallelization has been greatly improved. In the chemical field there are many tasks that require automation technology, because the control of the atmosphere may even take place under varying pressures, or work with different, partially volatile substances may occur. With small sample quantities and high automation costs, work is usually still carried out sequentially.

b) Full automation vs. partial automation

In principle, it is possible to automate all work steps, thus ensuring a comprehensive process. In this regard, it must be noted that the entire process also requires consumption programming, and the reaction possibilities are still limited by the results of the data feedback. By gradually introducing instruments to automate simple laboratory operations and to automate the implementation of complete tasks, decentralized automation systems can be created. Compared to most centralized systems, this offers greater flexibility. An error in one instrument does not lead to the collapse of the entire system, errors can be more easily localized and eliminated. Another point is the price/use assessment. Complete automation requires a lot of development work to promote the integration of existing modules and the development of the modules themselves. If this is not a pure research device, the cost of automation to promote the work steps must not exceed the expected benefits.

Solutions for chemical methods

Analysis of chemical samples Sample preparation is generally liquid handling. Liquid handling systems occupy a central position in laboratory automation. Simple systems limit the dosage of liquids to single or multiple tubes through pipettes or needles. In order to be able to automate the entire process, the integration of other functions such as shaking, heating, filtering, etc. is of great significance.

The corresponding system can be realized on the basis of the PAL pipette robot. The xyz robot is combined with different steps, so that the work of sample preparation steps, derivatization and sample delivery can be carried out in a measurable form. Integration with analytical measuring systems can be realized for GC 6890, GC/MS 5973, HPLC 1100, HPLC-MS VL (Agilent Technologies), HPLC LaChrom 7000 (Merck-Hitachi), Quattro II (Micromass) or FTICRMS Apex III (Bruker). Due to the flexible basic structure of the system, the number of possible derivatization programs is unlimited and can also be used for acylation, methylation, methylsilylation or analytical specific programs as well as simple sample preparation (dilution, standard adducts). Working under sample inert conditions is also possible. The system processes different sample formats, all of which, however, are added to the basic layout of the microtiter plate (Figure 1).

Figure 1 Kombi-PAL system for automated sample preparation and chemical sample analysis

If complex sample preparations are to be carried out in addition to pure liquid handling procedures, such as handling of solids as well as transport and processing of different containers, then a complex fully automated system is used. Such systems are generally not available on the market, but there are customer-specific solutions that can be designed and implemented under special conditions. The central machine is not combined with a number of individual steps (liquid handling, shaker, heater, stirrer, etc.), but assumes the function of a system integration that combines all the individual steps. The difficulty of this type of complex system is that instruments from different manufacturers and different hardware and software are combined to achieve continuous operation of the equipment. In order to control the complex system, a software solution is necessary, which allows operators without much project knowledge to operate it.

The corresponding system will be developed by the Institute of Automation Technology on the basis of the Zymate system. In addition to simple liquid handling in dosing pumps, it can also be used in the functional scope of the PAL system in conjunction with the above-mentioned Zymate machine. In addition to this, the system can also perform solid dosing, heating, shaking and stirring as well as handling of sample bottles (opening, closing, crimping). The connection of different analytical systems (GC, GC/MS, HPLC) enables complete automation of the analysis. Initially, the system was developed for complex sample preparation, as well as ground and water samples contaminated with chemical and biological agents, to reduce the need for personnel to handle toxic samples. Due to the flexible structure of the system, methods in the fields of PAK, chlorophenols, as well as catalysis or reaction optimization can be automated (Figure 2).

Biological sample preparation

In general, biological methods are based on simple analytical procedures, such as absorption, fluorescence or luminescence. However, before the actual measurement, many individual steps are often required. Sample preparation for biological methods places real demands, especially with regard to automation solutions. On the one hand, unlike chemical methods, large numbers of samples are required for the multi-step process. This also applies to the handling of individual samples and containers. Microtiter plates with up to 1536 wells are the standard. In addition, the handling of biological samples requires sterile conditions. The handling of cells or cell systems also presents great difficulties. [page]In addition

to simple automation solutions that allow for multi-step liquid handling, systems based on complex transfer machines are also being used in the field of biological sample preparation. Central machines combine the different steps (seals, piercers, incubators, card readers, gaskets, etc.) for sample transport. A high degree of flexibility in the basic system architecture is also a prerequisite. In order to be able to quickly adapt to different enzyme- or cell-based assays, the large number of samples to be processed and the time priorities of the individual steps place particularly high demands on the scheduling of the program, which should ensure the optimal use of the entire system.

Sometimes the requirement for aseptic conditions in cell systems makes automation more difficult. In addition to the cost issue, aseptic conditions must be achieved by storing the machine in ice. In particular, it must be ensured that all parts of the system used meet the sterility requirements (number of irradiated parts). This results in the system being able to be used in the aseptic area as well.

Future developments in the field of biological sample preparation are primarily related to the topic of automated cell handling. Automated cell cultivation will play an important role here, as will automated cell separation solutions (e.g. systems from Aviso GmbH). Solutions will be affected by the complete automation of the corresponding procedures (Figure 3).

Software solutions

Automated solutions also require rapid software development. This includes both the area of ​​programming experiments and equipment as well as the analytical use and archiving of the relevant data. In essence, this is a direct connection between sample preparation and analysis systems. It is therefore of certain importance to the user that all test-related data is entered into the computer once and the data is transferred via intelligent software solutions. The realization of a uniform software interface is an essential prerequisite for user acceptance (Figure 4).

For complex solutions, devices and systems that require many devices to implement, laboratory information management systems (LIMS) are available. Today, they are not only used for experimental planning, but also increasingly have direct instrument connections, which enable bidirectional data exchange. There is currently a growing trend towards the use of network-based systems. This is possible based on standardized intersections and integration with popular software packages. In addition, software upgrades can be simple, as there will be compatibility in the server range; however, additional and regular installations are not necessary for all users of computers, especially in systems with many users.

Outlook

The future development of sample preparation automation will depend on the situation of method development (chemical, biological, HTS, single sample processing or simultaneous sample processing), both in the field of single systems with a limited range of functions and in the field of complex stages or systems. In this regard, complex systems can be realized on a large scale in the future, first of all depending on the number of samples to be processed. In addition, the flexible combination of devices, which allows customers to operate without much procedural knowledge, will continue to play a key role in the acceptance or rejection of fully automated complex systems.

The introduction of unified integration formats is worth celebrating. In this way, the engineering costs for the integration and connection of different instruments and systems will be reduced and cost-effective solutions will appear on the market. The development of user-friendly software packages and LIM systems for the planning, implementation and documentation of analyses will also have a higher priority among other areas.