Nitrogen/Protein Determination In Milk Proteins By Dumas Combustion Method

Muhammad Ali,1 Bilal Khan,1 Liliana Krotz2 and Guido Giazzi2 1Vitalus Nutrition Inc., Abbotsford, BC, V2T 5W5 Canada, 2Thermo Fisher Scientific, Rodano, Milan, Italy

2 Nitrogen/Protein Determination In Milk Proteins By Dumas Combustion Method

Nitrogen/Protein Determination In Milk Proteins By Dumas Combustion Method Muhammad Ali1, Bilal Khan1, Liliana Krotz2 and Guido Giazzi2

1Vitalus Nutrition Inc., Abbotsford, BC, V2T 5W5 Canada, 2Thermo Fisher Scientific, Rodano, Milan, Italy

Conclusion The Thermo Scientific FLASH 2000 Nitrogen/Protein Analyzer is a valuable solution for the analysis of Nitrogen/Protein in terms of accuracy, reproducibility, sensitivity, automation, speed of analysis and cost per analysis. The system allows the analysis without matrix effect when changing the sample nature and Nitrogen content. The FLASH 2000 Elemental Analyzer also requires very low maintenance and is extremely robust and practical. Sample preparation is much easier as compared with Kjeldahl method and there are no hazardous wastes either. The system allows analyzing several different matrices with minimum or no changes to the methodology and the instrument itself. The auto-samplers are extremely efficient and is a very effective way of time and cost saving. Using autosamplers, several samples can be prepared once and then can be run on the instrument. The system is easy to install and service and requires very few changes to any laboratory systems and functionality.

Overview Purpose: Nitrogen/Protein determination by Dumas Combustion Method

Method: Milk protein concentrate samples are analyzed through an elemental analyzer with automatic autosampler.

Results: Nitrogen/Protein data of different milk protein concentrates and isolates demonstrates the validity of the method.

Introduction Milk proteins concentrates and isolates are used as ingredients in a wide variety of food applications. They are commonly found in infant formulas, enteral nutrition, bakery products, desserts, meat products, dairy based dry mixes (coffee whitener), dairy based drinks (UHT applications, coffee), sports nutrition and weight-loss beverages, protein bars, sauces, toppings, as well as processed cheese products. The composition and protein level is a determining factor in choosing the best MPC (Milk Protein Concentrate). One of the most important analysis in food ingredients is the determination of Nitrogen and Protein content applied for quality control and R&D purposes. So, for this, the use of accurate and automatic analytical techniques which allows the fast analysis with an excellent reproducibility is required. The Thermo Scientific™ FLASH™ 2000 Elemental Analyzer (Figure 1), based on the dynamic flash combustion of the sample, copes effortlessly with the wide array of laboratory requirements such as accuracy, day to day reproducibility and high sample throughput. This alternative to the classical Kjeldahl method, based on Dumas (combustion) method, has been developed and approved by different associations.

FIGURE 1. Thermo Scientific FLASH 2000 Elemental Analyzer.

FIGURE 2. N/Protein Layout.

Methods The Elemental Analyzer operates with the dynamic flash combustion of the sample. The sample is weighed in a Tin capsule and introduced into the combustion reactor via the Thermo Scientific™ MAS 200R™ Autosampler with a proper amount of Oxygen, ensuring a complete combustion of the sample. After the combustion, the produced gases are carried by a Helium flow to a second reactor filled with Copper, then swept through CO2 and H2O traps, a GC column and finally detected by the Thermal Conductivity Detector. Total run is 5 minutes (Figure 2). A complete N/Protein report is automatically generated by the Thermo Scientific™ Eager Xperience dedicated software and displayed at the end of the analysis.

Results Calibration method being used is the standard calibrating method developed by Thermo Scientific. For powder samples, 80-100 mg of aspartic acid is used as a standard and 200 - 300 mg of Pasta Reference Material is used as a secondary reference to check the calibration. For liquid dairy samples, water soluble urea is used as a standard at a desired concentration and then 80 ul is injected as a calibration method, manually or by Thermo Scientific™ AS 1310 Liquid Autosampler into the instrument. K factor was used as a calibration method. The protein content was calculated using the protein factor of 6.38. The protein conversion factor may vary depending on the type of matrix. Different types of milk protein concentrates and isolates were analyzed to evaluate the reproducibility of the system. Samples are directly weighed or injected into the instrument without any pre-treatment or any digestion and the weight used for analysis depends of the nature: 80 — 100 mg Milk Protein Concentrate samples, 100 — 150 mg Liquid cream samples and 80 — 100 mg ul Liquid concentrate samples. No memory effect on the results was observed changing the sample nature. Table 1 shows the protein results obtained with Milk Protein Concentrate samples when 80 — 100 mg of samples were analyzed in duplicate.

All trademarks are the property of Thermo Fisher Scientific and its subsidiaries. This information is not intended to encourage use of these products in any manners that might infringe the intellectual property rights of others. encourage use of these products in any manners that might infringe the intellectual property rights of others. Published at the Pittcon Conference and Expo, USA, New Orleans, March 2015. PO42226

TABLE 1. N/Protein data of Milk Protein Concentrate samples.

Table 2 shows the N/Protein results obtained when Liquid Concentrate samples were run on the instrument using the solids methodology. In this case, 30 - 50 mg of Chromosorb was used to absorb approximately 100 - 150 mg of samples. Samples were analyzed in duplicate.

TABLE 2. N/Protein data of Liquid Concentrate samples.

FIGURE 3. Thermo Scientific FLASH 2000 Analyzer. Table 3 shows the N/Protein results obtained when Dairy Liquid samples were run on the FLASH 2000 Analyzer using the liquid injection method; 80 ul of sample was injected and each sample was analyzed in duplicate.

TABLE 3. N/Protein data of Dairy Liquid samples.

3Thermo Scienti� c Poster Note • PITTCON • PN42226-EN 0215S

Nitrogen/Protein Determination In Milk Proteins By Dumas Combustion Method Muhammad Ali1, Bilal Khan1, Liliana Krotz2 and Guido Giazzi2

1Vitalus Nutrition Inc., Abbotsford, BC, V2T 5W5 Canada, 2Thermo Fisher Scientific, Rodano, Milan, Italy

Conclusion The Thermo Scientific FLASH 2000 Nitrogen/Protein Analyzer is a valuable solution for the analysis of Nitrogen/Protein in terms of accuracy, reproducibility, sensitivity, automation, speed of analysis and cost per analysis. The system allows the analysis without matrix effect when changing the sample nature and Nitrogen content. The FLASH 2000 Elemental Analyzer also requires very low maintenance and is extremely robust and practical. Sample preparation is much easier as compared with Kjeldahl method and there are no hazardous wastes either. The system allows analyzing several different matrices with minimum or no changes to the methodology and the instrument itself. The auto-samplers are extremely efficient and is a very effective way of time and cost saving. Using autosamplers, several samples can be prepared once and then can be run on the instrument. The system is easy to install and service and requires very few changes to any laboratory systems and functionality.

Overview Purpose: Nitrogen/Protein determination by Dumas Combustion Method

Method: Milk protein concentrate samples are analyzed through an elemental analyzer with automatic autosampler.

Results: Nitrogen/Protein data of different milk protein concentrates and isolates demonstrates the validity of the method.

Introduction Milk proteins concentrates and isolates are used as ingredients in a wide variety of food applications. They are commonly found in infant formulas, enteral nutrition, bakery products, desserts, meat products, dairy based dry mixes (coffee whitener), dairy based drinks (UHT applications, coffee), sports nutrition and weight-loss beverages, protein bars, sauces, toppings, as well as processed cheese products. The composition and protein level is a determining factor in choosing the best MPC (Milk Protein Concentrate). One of the most important analysis in food ingredients is the determination of Nitrogen and Protein content applied for quality control and R&D purposes. So, for this, the use of accurate and automatic analytical techniques which allows the fast analysis with an excellent reproducibility is required. The Thermo Scientific™ FLASH™ 2000 Elemental Analyzer (Figure 1), based on the dynamic flash combustion of the sample, copes effortlessly with the wide array of laboratory requirements such as accuracy, day to day reproducibility and high sample throughput. This alternative to the classical Kjeldahl method, based on Dumas (combustion) method, has been developed and approved by different associations.

FIGURE 1. Thermo Scientific FLASH 2000 Elemental Analyzer.

FIGURE 2. N/Protein Layout.

Methods The Elemental Analyzer operates with the dynamic flash combustion of the sample. The sample is weighed in a Tin capsule and introduced into the combustion reactor via the Thermo Scientific™ MAS 200R™ Autosampler with a proper amount of Oxygen, ensuring a complete combustion of the sample. After the combustion, the produced gases are carried by a Helium flow to a second reactor filled with Copper, then swept through CO2 and H2O traps, a GC column and finally detected by the Thermal Conductivity Detector. Total run is 5 minutes (Figure 2). A complete N/Protein report is automatically generated by the Thermo Scientific™ Eager Xperience dedicated software and displayed at the end of the analysis.

Results Calibration method being used is the standard calibrating method developed by Thermo Scientific. For powder samples, 80-100 mg of aspartic acid is used as a standard and 200 - 300 mg of Pasta Reference Material is used as a secondary reference to check the calibration. For liquid dairy samples, water soluble urea is used as a standard at a desired concentration and then 80 ul is injected as a calibration method, manually or by Thermo Scientific™ AS 1310 Liquid Autosampler into the instrument. K factor was used as a calibration method. The protein content was calculated using the protein factor of 6.38. The protein conversion factor may vary depending on the type of matrix. Different types of milk protein concentrates and isolates were analyzed to evaluate the reproducibility of the system. Samples are directly weighed or injected into the instrument without any pre-treatment or any digestion and the weight used for analysis depends of the nature: 80 — 100 mg Milk Protein Concentrate samples, 100 — 150 mg Liquid cream samples and 80 — 100 mg ul Liquid concentrate samples. No memory effect on the results was observed changing the sample nature. Table 1 shows the protein results obtained with Milk Protein Concentrate samples when 80 — 100 mg of samples were analyzed in duplicate.

All trademarks are the property of Thermo Fisher Scientific and its subsidiaries. This information is not intended to encourage use of these products in any manners that might infringe the intellectual property rights of others. encourage use of these products in any manners that might infringe the intellectual property rights of others. Published at the Pittcon Conference and Expo, USA, New Orleans, March 2015. PO42226

TABLE 1. N/Protein data of Milk Protein Concentrate samples.

Table 2 shows the N/Protein results obtained when Liquid Concentrate samples were run on the instrument using the solids methodology. In this case, 30 - 50 mg of Chromosorb was used to absorb approximately 100 - 150 mg of samples. Samples were analyzed in duplicate.

TABLE 2. N/Protein data of Liquid Concentrate samples.

FIGURE 3. Thermo Scientific FLASH 2000 Analyzer. Table 3 shows the N/Protein results obtained when Dairy Liquid samples were run on the FLASH 2000 Analyzer using the liquid injection method; 80 ul of sample was injected and each sample was analyzed in duplicate.

TABLE 3. N/Protein data of Dairy Liquid samples.

4 Nitrogen/Protein Determination In Milk Proteins By Dumas Combustion Method

Nitrogen/Protein Determination In Milk Proteins By Dumas Combustion Method Muhammad Ali1, Bilal Khan1, Liliana Krotz2 and Guido Giazzi2

1Vitalus Nutrition Inc., Abbotsford, BC, V2T 5W5 Canada, 2Thermo Fisher Scientific, Rodano, Milan, Italy

Conclusion The Thermo Scientific FLASH 2000 Nitrogen/Protein Analyzer is a valuable solution for the analysis of Nitrogen/Protein in terms of accuracy, reproducibility, sensitivity, automation, speed of analysis and cost per analysis. The system allows the analysis without matrix effect when changing the sample nature and Nitrogen content. The FLASH 2000 Elemental Analyzer also requires very low maintenance and is extremely robust and practical. Sample preparation is much easier as compared with Kjeldahl method and there are no hazardous wastes either. The system allows analyzing several different matrices with minimum or no changes to the methodology and the instrument itself. The auto-samplers are extremely efficient and is a very effective way of time and cost saving. Using autosamplers, several samples can be prepared once and then can be run on the instrument. The system is easy to install and service and requires very few changes to any laboratory systems and functionality.

Overview Purpose: Nitrogen/Protein determination by Dumas Combustion Method

Method: Milk protein concentrate samples are analyzed through an elemental analyzer with automatic autosampler.

Results: Nitrogen/Protein data of different milk protein concentrates and isolates demonstrates the validity of the method.

Introduction Milk proteins concentrates and isolates are used as ingredients in a wide variety of food applications. They are commonly found in infant formulas, enteral nutrition, bakery products, desserts, meat products, dairy based dry mixes (coffee whitener), dairy based drinks (UHT applications, coffee), sports nutrition and weight-loss beverages, protein bars, sauces, toppings, as well as processed cheese products. The composition and protein level is a determining factor in choosing the best MPC (Milk Protein Concentrate). One of the most important analysis in food ingredients is the determination of Nitrogen and Protein content applied for quality control and R&D purposes. So, for this, the use of accurate and automatic analytical techniques which allows the fast analysis with an excellent reproducibility is required. The Thermo Scientific™ FLASH™ 2000 Elemental Analyzer (Figure 1), based on the dynamic flash combustion of the sample, copes effortlessly with the wide array of laboratory requirements such as accuracy, day to day reproducibility and high sample throughput. This alternative to the classical Kjeldahl method, based on Dumas (combustion) method, has been developed and approved by different associations.

FIGURE 1. Thermo Scientific FLASH 2000 Elemental Analyzer.

FIGURE 2. N/Protein Layout.

Methods The Elemental Analyzer operates with the dynamic flash combustion of the sample. The sample is weighed in a Tin capsule and introduced into the combustion reactor via the Thermo Scientific™ MAS 200R™ Autosampler with a proper amount of Oxygen, ensuring a complete combustion of the sample. After the combustion, the produced gases are carried by a Helium flow to a second reactor filled with Copper, then swept through CO2 and H2O traps, a GC column and finally detected by the Thermal Conductivity Detector. Total run is 5 minutes (Figure 2). A complete N/Protein report is automatically generated by the Thermo Scientific™ Eager Xperience dedicated software and displayed at the end of the analysis.

Results Calibration method being used is the standard calibrating method developed by Thermo Scientific. For powder samples, 80-100 mg of aspartic acid is used as a standard and 200 - 300 mg of Pasta Reference Material is used as a secondary reference to check the calibration. For liquid dairy samples, water soluble urea is used as a standard at a desired concentration and then 80 ul is injected as a calibration method, manually or by Thermo Scientific™ AS 1310 Liquid Autosampler into the instrument. K factor was used as a calibration method. The protein content was calculated using the protein factor of 6.38. The protein conversion factor may vary depending on the type of matrix. Different types of milk protein concentrates and isolates were analyzed to evaluate the reproducibility of the system. Samples are directly weighed or injected into the instrument without any pre-treatment or any digestion and the weight used for analysis depends of the nature: 80 — 100 mg Milk Protein Concentrate samples, 100 — 150 mg Liquid cream samples and 80 — 100 mg ul Liquid concentrate samples. No memory effect on the results was observed changing the sample nature. Table 1 shows the protein results obtained with Milk Protein Concentrate samples when 80 — 100 mg of samples were analyzed in duplicate.

All trademarks are the property of Thermo Fisher Scientific and its subsidiaries. This information is not intended to encourage use of these products in any manners that might infringe the intellectual property rights of others. encourage use of these products in any manners that might infringe the intellectual property rights of others. Published at the Pittcon Conference and Expo, USA, New Orleans, March 2015. PO42226

TABLE 1. N/Protein data of Milk Protein Concentrate samples.

Table 2 shows the N/Protein results obtained when Liquid Concentrate samples were run on the instrument using the solids methodology. In this case, 30 - 50 mg of Chromosorb was used to absorb approximately 100 - 150 mg of samples. Samples were analyzed in duplicate.

TABLE 2. N/Protein data of Liquid Concentrate samples.

FIGURE 3. Thermo Scientific FLASH 2000 Analyzer. Table 3 shows the N/Protein results obtained when Dairy Liquid samples were run on the FLASH 2000 Analyzer using the liquid injection method; 80 ul of sample was injected and each sample was analyzed in duplicate.

TABLE 3. N/Protein data of Dairy Liquid samples.

5Thermo Scienti� c Poster Note • PITTCON • PN42226-EN 0215S

Nitrogen/Protein Determination In Milk Proteins By Dumas Combustion Method Muhammad Ali1, Bilal Khan1, Liliana Krotz2 and Guido Giazzi2

1Vitalus Nutrition Inc., Abbotsford, BC, V2T 5W5 Canada, 2Thermo Fisher Scientific, Rodano, Milan, Italy

Conclusion The Thermo Scientific FLASH 2000 Nitrogen/Protein Analyzer is a valuable solution for the analysis of Nitrogen/Protein in terms of accuracy, reproducibility, sensitivity, automation, speed of analysis and cost per analysis. The system allows the analysis without matrix effect when changing the sample nature and Nitrogen content. The FLASH 2000 Elemental Analyzer also requires very low maintenance and is extremely robust and practical. Sample preparation is much easier as compared with Kjeldahl method and there are no hazardous wastes either. The system allows analyzing several different matrices with minimum or no changes to the methodology and the instrument itself. The auto-samplers are extremely efficient and is a very effective way of time and cost saving. Using autosamplers, several samples can be prepared once and then can be run on the instrument. The system is easy to install and service and requires very few changes to any laboratory systems and functionality.

Overview Purpose: Nitrogen/Protein determination by Dumas Combustion Method

Method: Milk protein concentrate samples are analyzed through an elemental analyzer with automatic autosampler.

Results: Nitrogen/Protein data of different milk protein concentrates and isolates demonstrates the validity of the method.

Introduction Milk proteins concentrates and isolates are used as ingredients in a wide variety of food applications. They are commonly found in infant formulas, enteral nutrition, bakery products, desserts, meat products, dairy based dry mixes (coffee whitener), dairy based drinks (UHT applications, coffee), sports nutrition and weight-loss beverages, protein bars, sauces, toppings, as well as processed cheese products. The composition and protein level is a determining factor in choosing the best MPC (Milk Protein Concentrate). One of the most important analysis in food ingredients is the determination of Nitrogen and Protein content applied for quality control and R&D purposes. So, for this, the use of accurate and automatic analytical techniques which allows the fast analysis with an excellent reproducibility is required. The Thermo Scientific™ FLASH™ 2000 Elemental Analyzer (Figure 1), based on the dynamic flash combustion of the sample, copes effortlessly with the wide array of laboratory requirements such as accuracy, day to day reproducibility and high sample throughput. This alternative to the classical Kjeldahl method, based on Dumas (combustion) method, has been developed and approved by different associations.

FIGURE 1. Thermo Scientific FLASH 2000 Elemental Analyzer.

FIGURE 2. N/Protein Layout.

Methods The Elemental Analyzer operates with the dynamic flash combustion of the sample. The sample is weighed in a Tin capsule and introduced into the combustion reactor via the Thermo Scientific™ MAS 200R™ Autosampler with a proper amount of Oxygen, ensuring a complete combustion of the sample. After the combustion, the produced gases are carried by a Helium flow to a second reactor filled with Copper, then swept through CO2 and H2O traps, a GC column and finally detected by the Thermal Conductivity Detector. Total run is 5 minutes (Figure 2). A complete N/Protein report is automatically generated by the Thermo Scientific™ Eager Xperience dedicated software and displayed at the end of the analysis.

Results Calibration method being used is the standard calibrating method developed by Thermo Scientific. For powder samples, 80-100 mg of aspartic acid is used as a standard and 200 - 300 mg of Pasta Reference Material is used as a secondary reference to check the calibration. For liquid dairy samples, water soluble urea is used as a standard at a desired concentration and then 80 ul is injected as a calibration method, manually or by Thermo Scientific™ AS 1310 Liquid Autosampler into the instrument. K factor was used as a calibration method. The protein content was calculated using the protein factor of 6.38. The protein conversion factor may vary depending on the type of matrix. Different types of milk protein concentrates and isolates were analyzed to evaluate the reproducibility of the system. Samples are directly weighed or injected into the instrument without any pre-treatment or any digestion and the weight used for analysis depends of the nature: 80 — 100 mg Milk Protein Concentrate samples, 100 — 150 mg Liquid cream samples and 80 — 100 mg ul Liquid concentrate samples. No memory effect on the results was observed changing the sample nature. Table 1 shows the protein results obtained with Milk Protein Concentrate samples when 80 — 100 mg of samples were analyzed in duplicate.

All trademarks are the property of Thermo Fisher Scientific and its subsidiaries. This information is not intended to encourage use of these products in any manners that might infringe the intellectual property rights of others. encourage use of these products in any manners that might infringe the intellectual property rights of others. Published at the Pittcon Conference and Expo, USA, New Orleans, March 2015. PO42226

TABLE 1. N/Protein data of Milk Protein Concentrate samples.

Table 2 shows the N/Protein results obtained when Liquid Concentrate samples were run on the instrument using the solids methodology. In this case, 30 - 50 mg of Chromosorb was used to absorb approximately 100 - 150 mg of samples. Samples were analyzed in duplicate.

TABLE 2. N/Protein data of Liquid Concentrate samples.

FIGURE 3. Thermo Scientific FLASH 2000 Analyzer. Table 3 shows the N/Protein results obtained when Dairy Liquid samples were run on the FLASH 2000 Analyzer using the liquid injection method; 80 ul of sample was injected and each sample was analyzed in duplicate.

TABLE 3. N/Protein data of Dairy Liquid samples.

PN42226-EN 0215S

Nitrogen/Protein Determination In Milk Proteins By Dumas Combustion Method Muhammad Ali1, Bilal Khan1, Liliana Krotz2 and Guido Giazzi2

1Vitalus Nutrition Inc., Abbotsford, BC, V2T 5W5 Canada, 2Thermo Fisher Scientific, Rodano, Milan, Italy

Conclusion The Thermo Scientific FLASH 2000 Nitrogen/Protein Analyzer is a valuable solution for the analysis of Nitrogen/Protein in terms of accuracy, reproducibility, sensitivity, automation, speed of analysis and cost per analysis. The system allows the analysis without matrix effect when changing the sample nature and Nitrogen content. The FLASH 2000 Elemental Analyzer also requires very low maintenance and is extremely robust and practical. Sample preparation is much easier as compared with Kjeldahl method and there are no hazardous wastes either. The system allows analyzing several different matrices with minimum or no changes to the methodology and the instrument itself. The auto-samplers are extremely efficient and is a very effective way of time and cost saving. Using autosamplers, several samples can be prepared once and then can be run on the instrument. The system is easy to install and service and requires very few changes to any laboratory systems and functionality.

Overview Purpose: Nitrogen/Protein determination by Dumas Combustion Method

Method: Milk protein concentrate samples are analyzed through an elemental analyzer with automatic autosampler.

Results: Nitrogen/Protein data of different milk protein concentrates and isolates demonstrates the validity of the method.

Introduction Milk proteins concentrates and isolates are used as ingredients in a wide variety of food applications. They are commonly found in infant formulas, enteral nutrition, bakery products, desserts, meat products, dairy based dry mixes (coffee whitener), dairy based drinks (UHT applications, coffee), sports nutrition and weight-loss beverages, protein bars, sauces, toppings, as well as processed cheese products. The composition and protein level is a determining factor in choosing the best MPC (Milk Protein Concentrate). One of the most important analysis in food ingredients is the determination of Nitrogen and Protein content applied for quality control and R&D purposes. So, for this, the use of accurate and automatic analytical techniques which allows the fast analysis with an excellent reproducibility is required. The Thermo Scientific™ FLASH™ 2000 Elemental Analyzer (Figure 1), based on the dynamic flash combustion of the sample, copes effortlessly with the wide array of laboratory requirements such as accuracy, day to day reproducibility and high sample throughput. This alternative to the classical Kjeldahl method, based on Dumas (combustion) method, has been developed and approved by different associations.

FIGURE 1. Thermo Scientific FLASH 2000 Elemental Analyzer.

FIGURE 2. N/Protein Layout.

Methods The Elemental Analyzer operates with the dynamic flash combustion of the sample. The sample is weighed in a Tin capsule and introduced into the combustion reactor via the Thermo Scientific™ MAS 200R™ Autosampler with a proper amount of Oxygen, ensuring a complete combustion of the sample. After the combustion, the produced gases are carried by a Helium flow to a second reactor filled with Copper, then swept through CO2 and H2O traps, a GC column and finally detected by the Thermal Conductivity Detector. Total run is 5 minutes (Figure 2). A complete N/Protein report is automatically generated by the Thermo Scientific™ Eager Xperience dedicated software and displayed at the end of the analysis.

Results Calibration method being used is the standard calibrating method developed by Thermo Scientific. For powder samples, 80-100 mg of aspartic acid is used as a standard and 200 - 300 mg of Pasta Reference Material is used as a secondary reference to check the calibration. For liquid dairy samples, water soluble urea is used as a standard at a desired concentration and then 80 ul is injected as a calibration method, manually or by Thermo Scientific™ AS 1310 Liquid Autosampler into the instrument. K factor was used as a calibration method. The protein content was calculated using the protein factor of 6.38. The protein conversion factor may vary depending on the type of matrix. Different types of milk protein concentrates and isolates were analyzed to evaluate the reproducibility of the system. Samples are directly weighed or injected into the instrument without any pre-treatment or any digestion and the weight used for analysis depends of the nature: 80 — 100 mg Milk Protein Concentrate samples, 100 — 150 mg Liquid cream samples and 80 — 100 mg ul Liquid concentrate samples. No memory effect on the results was observed changing the sample nature. Table 1 shows the protein results obtained with Milk Protein Concentrate samples when 80 — 100 mg of samples were analyzed in duplicate.

All trademarks are the property of Thermo Fisher Scientific and its subsidiaries. This information is not intended to encourage use of these products in any manners that might infringe the intellectual property rights of others. encourage use of these products in any manners that might infringe the intellectual property rights of others. Published at the Pittcon Conference and Expo, USA, New Orleans, March 2015. PO42226

TABLE 1. N/Protein data of Milk Protein Concentrate samples.

Table 2 shows the N/Protein results obtained when Liquid Concentrate samples were run on the instrument using the solids methodology. In this case, 30 - 50 mg of Chromosorb was used to absorb approximately 100 - 150 mg of samples. Samples were analyzed in duplicate.

TABLE 2. N/Protein data of Liquid Concentrate samples.

FIGURE 3. Thermo Scientific FLASH 2000 Analyzer. Table 3 shows the N/Protein results obtained when Dairy Liquid samples were run on the FLASH 2000 Analyzer using the liquid injection method; 80 ul of sample was injected and each sample was analyzed in duplicate.

TABLE 3. N/Protein data of Dairy Liquid samples.

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