The principle of the EIM-IRMS® method is based on the dehydration of ethanol using an EIM catalyst, specially developed by SG Isotech, followed by pyrolysis of gas and measurement of the relative ratio of Hydrogenstable isotopes in the Hydrogen gas created.
All products containing ethanol or fermentable sugars can be prepared for analysis by the EIM-IRMS method and equipment. As the abbreviation EIM itself suggests, it is an Ethanol Isotope Measurement concept, so the main analyte under test is Ethanol. Fermentable sugars must first be converted to Ethanol, which is analyzed for the botanical origin of the starting material used in production.
The alcoholic strength of the wine distillate should be greater than 92% vol.
From 30 to 40 samples can be analyzed within a single sequence.
Analytical kits for each type of product being tested are available for purchase. These kits contain everything needed for the analysis and can be purchased from SG Isotech. One kit is sufficient for the analysis of 100 to 400 samples depending on the kit purchased.
EIMPyro uses AI1310 Liquid Autosampler peripheral, but will also work with AS3000 or GC Pal Autosamplers for liquid samples.
When performing analysis, 3-5 injections or each sample should be done.
SG Isotech has developed software called “EIM9000” which is used for calculation of dDn results. It comes as a standard package with EIM-Pyro. It also calculates average dDn value and SD for each analyzed sample.
After connecting the EIM-Pyro peripherals to the isotope ratio MS and after raising the temperature in the reactors, it is necessary to determine whether all the connections are leak-free before starting the sequence. By switching the mass on the middle detector to 40 (Argon) it is necessary to monitor the background which should be below 40 mV. Leak checking must be performed before each analysis begins. If the leakage is higher, it is necessary to check all connections. As a rule start from the closest connection to the furthest connection from IRMS.
The NMR concept is based on the technique of counting deuterium atoms on a methyl and methylene group of ethanol, which oscillate at appropriate frequencies in a strong magnetic field. EIM technique is based on determining the dD values of non-exchangeable stable isotopes of Hydrogen in ethanol. The analytical values obtained by both techniques are very precise, but there is a difference in the natural ranges of these analytical parameters for ethanol with a different botanical origin, and accordingly a difference in the level of detection of illegal production practices in the production of wine, fruit juices, alcoholic beverages, and honey. For NMR this difference for ethanol with the different botanical origin is only 1 ppm, while for EIM it is about 50 ‰ on a relative scale, making EIM method a lot more precise.
The accuracy of measurement is expressed by the precision limits of the repeatability and reproducibility which can be calculated from the sample standard deviation of the results. The repeatability precision limit (r) and the reproducibility precision limit (R) for EIM-IRMS are calculated as follows:
r = 2.8 × sr = 2.7‰ ;
R = 2.8 × sR = 2.13 ‰
Where:
- sR - Interlaboratory Reproducibility standard deviation as Standard deviation of all measurements of the same sample expressed in ‰
- sr − Interlaboratory Repeatability standard deviation as the average standard deviation for the same sample expressed in ‰
The analysis of one sample takes 5-8 minutes.
Yes, there is no problem to analyze ethanol samples from different sources.
Ethanol is firstly quantitatively dehydrated without isotopic fractionation over specifically designed EIM Catalyst and then pyrolyzed and elemental Hydrogen gas is obtained.
If by any chance a distillate of less than 92% vol is obtained, the distillation process of the sample should be repeated and the alcoholic strength and recovery determined again.
EIM-Pyro peripheral automatically controls the temperature of the reactors. There is no need to manually raise or lower the temperature, but this option also exists.
Approximately 3-4 hours.
EIM-Pyro works under standard room temperature conditions, just like the IRMS it is connected to. Recommended room temperature is 15°C to 25°C.
EIM-PADS is a shortcut for Ethanol Isotope Measurement – Preparation Automatic Distillation System. It is a fully automated distillation system.
EIM-PADS system can contain up to 10 distillation units in any denomination.
Wine, fermented fruit juices, fermented honey as well as alcoholic beverages can be distilled on the EIM-PADS system.
Of course, it is possible to distill multiple samples simultaneously, regardless of their origin.
The volume of the sample to be distilled is always the same, and is 250 mL.
The volume of the distillation flask is 500 mL.
The whole distillation process is fully automated and software-driven, so the process ends automatically when ethanol is completely pre-distilled and converted to the distillate.
Distillation begins when the temperature at the top of the distillation unit reaches 78.2 °C and ends when the temperature exceeds the value of 79 °C. The ethanol evaporation temperature is between this range. As soon as the temperature exits this range, it means that there is no more ethanol in the superheated steam and that the distillation process is complete.
Temperature is controlled by EIM9000 software, which comes with the system.
Sample names can be entered into the EIM9000 program.
The distillation time depends on the amount of ethanol in the sample. The average distillation process varies from 1 to 2 hours.
Distillation may be stopped at any time, but it is not advisable. In case it was only partially distilled, it is not advisable to use distillate for authentication because the process is not complete and is not quantitative by itself. Ethanol must be quantitatively extracted from the sample to be analyzed in order for the results to be reliable and valid.
It is advisable to keep ethanol distillate samples in the refrigerator at low temperature to avoid evaporation and hence isotopic fractionation and loss of sample origin information.
It is not possible to concentrate ethanol by standard distillation to the ethanol concentrations obtained on EIM-PADS.
The space occupied by EIM-PADS depends on the number of distillation units within a single battery. Dimensions and weight of one distillation unit is 500mm x 400mm x 1500mm (W x D x H); 30kg NET weight.
SG Isotech specializes in research, development, and production of analytical instrumentation equipment for the authentication of food products. Our technology is based on the determination of stable isotopes of light elements such as Hydrogen, Carbon, Oxygen, Nitrogen, and Sulfur.
SG Isotech was founded in 2013 in the Republic of Serbia.
SG Isotech currently has collaborations with scientific institutions and scientific teams (laboratories and research centers) in the US, Austria, Hungary, and the Russian Federation.