Nitrogen/protein analyser to ensure high sample throughput for lab

Environmental research institute required an instrument with the capacity to efficiently and accurately analyse nitrogen/protein in animal feed and in human food samples.

The Research Institute - Gruppo CSA SpA was founded in 1985 by a group of self-professed 'young and enthusiastic' researchers, with the intent of creating an institute that nurtured the innovative development of environmental analyses in a multidisciplinary way. Located in Rimini, Italy, the laboratory processes 70000 samples and determines over 800000 parameters every year. Divisions within Gruppo CSA cover a broad range of areas including environmental sampling, physical analyses, industrial hygiene, food hygiene, water analyses, research and development and agriculture. The institute is accredited according to the standard UNI CEI EN ISO/IEC 9001:2008 and UNI CEI EN ISO/IEC 14001: 2004 for chemical analysis and environmental services, certifying the quality of both the methods used and the data obtained within the institute laboratories. Working in collaboration with multiple university research institutes and private and public laboratories, CSA offers an innovative and professional service to a diverse customer base.[Page Break]

The challenge

The institute's food laboratory division performs a broad range of analyses including nutritional evaluation, multi-residual pesticide analysis and the analysis of protein within animal feed and human food samples. Protein is one of the most important nutrients when determining the nutritional quality of a product and is typically calculated through the determination of nitrogen. When determining the quantity of protein in a product, Gruppo CSA must adhere to the AOAC method 992.23 which indicates that the suitable fineness of grind must be determined to achieve precision that gives RDS of ≤2 percent for 10 successive determinations of nitrogen.

On an ongoing basis the company is required to conduct nitrogen/protein analysis on alfalfa, a common hay crop primarily used as live stock feed due to its high protein content. A recent initiative established by The Commission of the European Communities provides a financial incentive for farmers producing dehydrated alfalfa with levels of protein above 15 percent. As a result, Gruppo CSA receives a particularly high demand for the rapid analysis of nitrogen/protein in high quantities of dehydrated alfalfa.

Since the company's inception, the laboratory has utilised the traditional Kjeldahl method for protein analysis. However, this method suffers from a number of challenges. One of the key drawbacks for Gruppo CSA is that the Kjeldahl method is extremely time consuming, requiring over four hours to complete a single analytical cycle while also being limited to a maximum of just 20 samples per cycle. This is due to the various time consuming stages involved in the process, including sample digestion in boiling sulfuric acid, neutralisation with sodium hydroxide solution, distillation of the resulting ammonia gas into a trapping solution, titration with an acid solution and determination of nitrogen/protein content by calculation.

Dr Pierpaolo Tentoni, chairman of Gruppo CSA comments: "Although the Kjeldahl method has been modified and improved since its initial development, the method still requires the use of acids at extremely high temperatures. This can have a corrosive effect on our instrumentation alongside posing a serious health and safety threat to our technicians." Additionally, the Kjeldahl method suffers from issues of toxic waste generation due to the deployment of mercury or selenium as catalysts for digestion. As a result, a chimney is required within the laboratory to remove the waste, which incurs a high expense and raises the problem of pollution excreted into the environment. Due to these factors, the Kjeldahl method cannot be operated continuously which reduces sample throughput, and as a consequence drives up the cost of these services for the institute.

To overcome these challenges the laboratory required a solution that would increase overall productivity and cost-efficiency, while also improving health and safety conditions and remaining compliant with existing industry regulations. In order to achieve its goals, Gruppo CSA began to explore alternative protein analysis techniques.[Page Break]


Gruppo CSA has recently implemented the Thermo Scientific FLASH 4000 nitrogen/protein analyser for the determination and quantification of protein in dehydrated alfalfa and other forms of animal feed. The analyser has been designed to work with the Dumas combustion method for protein analysis which is recognized by the Association of Official Analytical Chemists (AOAC) and the American Oil Chemist Society (AOCS) as an alternative to the Kjeldahl method.

Prior to the purchase of the FLASH 4000 nitrogen/protein analyser, Gruppo CSA had extensive experience with Thermo Scientific instruments, which instilled confidence in their new selection. Dr Tentoni said: "Before selecting the Thermo Scientific FLASH 4000 nitrogen/protein analyser, we spent time comparing competitive solutions. After conducting a comprehensive evaluation of the FLASH 4000 it became clear that the analyser is unmatched in terms of capacity for accuracy, sample throughput and sheer efficiency when facilitating the Dumas technique. Our decision was also informed by the institute's positive experiences with a range of other Thermo Scientific instrumentation, including an OEA unit which was purchased eight years ago and continues to be an efficient and valuable tool in the laboratory."[Page Break]

Key benefits

Since the implementation of the new analyzer, Gruppo CSA has experienced significant benefits for its protein analyses. Previously when using the Kjeldahl method, the laboratory was limited to a batch of 20 samples per cycle. The FLASH 4000 now enables the team to process up to 50 samples in a single cycle. In addition, the four hour cycle time has been dramatically reduced to just 10 minutes, increasing throughput by over 50 per cent. It is estimated that the laboratory will now be able to process over 7000 samples each year.

Dr Tentoni comments: "In contrast to the Kjeldahl method which requires constant monitoring by our technicians, the FLASH 4000 requires no human presence. As a result, analytical cycles can be left to run overnight and unattended, saving technician time and increasing overall throughput. Due to the limited sample capacity and the high cost associated with the Kjedlahl method, we were previously unable to analyze animal feed samples for farmers and producers, who required large quantities of samples to be analyzed at low cost. With the high sample capacity and cost-efficiency of the FLASH 4000, for the first time ever we have been able to provide animal feed analysis as a key service."

An additional benefit of the FLASH 4000 is the elimination of aggressive mixtures such as base acid and fumes. Dr Tentoni says: "The new instrument does not require the use of corrosive acids, making it much safer for our laboratory technicians and more environmentally friendly. Furthermore, the removal of the acids and toxic reagents has meant that the instrument is much easier to clean and maintain, particularly with the inclusion of the self-cleaning filter, saving both time and money."[Page Break]


To meet its objectives Gruppo CSA needed an alternative to the Kjeldahl method for protein analysis that would improve overall productivity within the laboratory while also ensuring the safety of the institute's technicians and reducing overall costs. The institute also required a method that would enable the team to provide cost-effective animal feed analysis as a service, particularly with complex matrices such as dehydrated alfalfa which is currently in high demand within the agricultural community.

Prior to the purchase of the FLASH 4000 nitrogen/protein analyzer, Gruppo CSA was unable to provide nitrogen/protein analysis of animal feed as a service due to sample throughput being limited to just 20 samples per cycle. Since implementing the new analyzer, the laboratory's throughput has doubled enabling the institute to expand its services and customer base significantly. In addition, with the removal of dangerous and corrosive acids used for the Kjeldahl method, the health and safety conditions within the laboratory have improved.

Dr Tentoni comments: "We selected the Thermo Scientific FLASH 4000 nitrogen/protein analyser based on its capacity to work with the Dumas method. Since its deployment we have been able to expand our services and increase the speed and quantity of samples being processed, while also improving the precision and accuracy of our results."

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