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History of ASTM International
The American Society for Testing and Materials (ASTM) is an organization that currently provides over 12,500 international standards. Its roots date back to 1898, when ASTM was formed by a group of scientists and engineers to address the frequent rail breaks affecting the fast-growing railroad industry. The group developed a standard for the steel used to fabricate rails.
Originally, this organization was called the «American Society for Testing Materials» (1902) and was changed to the «American Society for Testing and Materials» in 1961. In 2001, ASTM officially changed its name to «ASTM International» and added the tagline «Standards Worldwide». This tagline was modified in 2014 to «Helping our world work better». Now, aside from the US, ASTM International also has offices in Belgium, Canada, China, and Peru.
ASTM International aims to ensure that quality and standard requirements are met when using materials for engineering projects. Therefore, they had to agree upon a single language for engineers and technicians to enhance compatibility, and ultimately developed a system grouped according to industries in the form of letters A–G. Currently, there are over 12,500 ASTM standards used by about 150 countries. This has increased trade in different markets by instilling and strengthening consumer confidence.
ASTM Committee D02 on Petroleum Products, Liquid Fuels, and Lubricants
Formed in 1904, ASTM Committee D02 currently meets twice per year for five days of technical meetings, attended by approximately 1000 members (out of around 2500). D02 has jurisdiction over 814 standards with a prominent role in all aspects relating to the standardization of petroleum products and lubricants, which are published in the Annual Book of ASTM Standards (Volumes 05.01 through 05.06).
Near-infrared spectroscopy—an ASTM compliant tool to assess the quality of petrochemical products
Near-infrared spectroscopy (NIRS) has been an established method for fast and reliable quality control within the petrochemical industry for more than 30 years. However, many companies still do not consistently consider the implementation of NIRS in their QA/QC labs. The reasons could be either limited experience regarding application possibilities or a general hesitation about implementing NIRS as an alternative technology.
Many companies are not aware that now there are many ASTM standards about how to implement NIR spectroscopy as an alternative to conventional methods. Several NIRS-related ASTM guidelines are shown in Figure 1.
ASTM E1655 (method development quantitative NIR analysis) and ASTM E1790 (method development qualitative NIR analysis) are applicable for all industries (e.g., polymer, chemical, petrochemical, etc.).
ASTM D6122 (method validation), ASTM D8321 (development and validation of multivariate analysis), and ASTM D8340 (performance qualification) are dedicated for the petrochemical industry. These three standards were released recently in 2020, and ASTM D8340 was updated at the end of 2021.
Method development
ASTM E1655: Standard Practices for Infrared Multivariate Quantitative Analysis
«These practices cover a guide for the multivariate calibration of infrared spectrometers used in determining the physical or chemical characteristics of materials. These practices are applicable to analyses conducted in the near infrared (NIR) spectral region (roughly 780 to 2500 nm).»
ASTM E1790: Standard Practice for Near Infrared Qualitative Analysis
«This practice covers the use of near-infrared (NIR) spectroscopy for the qualitative analysis of liquids and solids. The practice is written under the assumption that most NIR qualitative analyses will be performed with instruments designed specifically for this purpose and equipped with computerized data handling algorithms.»
Method validation
ASTM D6122: Standard Practice for Validation of the Performance of Multivariate Online, At-Line, Field and Laboratory Infrared Spectrophotometer, and Raman Spectrometer Based Analyzer Systems
«This practice covers requirements for the validation of measurements made by laboratory, field, or process (online or at-line) infrared (near- or mid-infrared analyzers, or both), and Raman analyzers, used in the calculation of physical, chemical, or quality parameters (that is, properties) of liquid petroleum products and fuels.»
These requirements include the following topics:
- Analyzer calibration
- Correlation of NIRS vs. lab method (treated and untreated samples)
- Probationary validation
- General & Continual validation
Results validation
ASTM D8321: Standard Practice for Development and Validation of Multivariate Analyses for Use in Predicting Properties of Petroleum Products, Liquid Fuels, and Lubricants based on Spectroscopic Measurements
«This practice covers a guide for the multivariate calibration of infrared (IR) spectrophotometers and Raman spectrometers used in determining the physical, chemical, and performance properties of petroleum products, liquid fuels including biofuels, and lubricants. This practice is applicable to analyses conducted in the near infrared (NIR) spectral region (roughly 780 nm to 2500 nm).»
The main purpose for this standard is to establish the validity of test results during calibration.
ASTM D8340: Standard Practice for Performance-Based Qualification of Spectroscopic Analyzer Systems
«This practice covers requirements for establishing performance-based qualification of vibrational spectroscopic analyzer systems intended to be used to predict the test result of a material that would be produced by a Primary Test Method (PTM) if the same material is tested by the PTM.»
Furthermore, it includes the prescriptive requirements regarding multivariate models, including Multi Linear Regression (MLR), Partial Least Square (PLS), Principal Component Regression (PCR), Cross validation, and Outlier statistics, as well as instrument considerations.
Regarding the required accuracy of the NIRS method the expected agreement and user requirements is that the Standard Error of Prediction for the NIRS value should be equal to or smaller than the laboratory method reproducibility.
ASTM D8340 compliance with the NIRS DS2500 Petro Analyzer and Vision Air
Temperature stability, section 5.4:
There are prescriptive requirements included in this norm regarding temperature stability of the NIRS Analyzer. Section 5.4 requires sample temperature to be carefully controlled in the analyzer system hardware or that effects of temperature change be compensated in the modeling or software. Metrohm’s solution to this issue for the NIRS DS2500 Petro Analyzer is shown in Figure 2.
Learn more about the possibilities of petrochemical analysis with Metrohm NIRS DS2500 Petro Analyzers in our free brochure.
Analyzer wavelength accuracy and precision, section 6.3:
Section 6.3 requires that the analyzer shall include a means of demonstrating that it is operating within the vendor’s specification. Therefore, the analyzer shall incorporate instrument performance tests to demonstrate that it is operating within historically expected limits. Furthermore, the analyzer shall have a means of validating wavelength/frequency precision and accuracy. Also, the wavelength precision must be sufficient to allow spectra to be collected and used in creating a multivariate model that meets or exceeds user’s specifications. The wavelength precision of the analyzer used for calibration and the analyzer-to-analyzer wavelength accuracy and reproducibility must be sufficient to allow analyzers to be validated by Practice D6122. Metrohm’s solution to this is the Vision Air software shown in Figure 3.
Vendor created global multivariate model, section 8.2.2:
The multivariate model can be that of a standardized test method, a user/vendor-created global multivariate model, or a user-created site-specific multivariate model. A global multivariate model is one developed by use of samples and data that may represent materials produced at multiple facilities or locations. Some locations may start with a global model and add site-specific sample to it. Metrohm offers several pre-calibrations for the NIRS DS2500 Petro Analyzer, listed in Figure 4.
Discover our selection of NIRS pre-calibrations available for the petrochemical industry in our free brochure.
Brochure: Quality control of fuels - Fast results with NIR pre-calibrations
Outlier statistics, sections 9.3, 9.4, and 9.5:
The requirements of outlier handling are described in these sections. Identification and handling of outliers is important to the success of meeting this performance-based practice. It is permissible for the identification and handling of outliers to be performed by the same or separate software used for generating predictions from spectra. For analysis of a sample for the purposes of determining property values, the software shall indicate whether the spectrum is identified as an outlier, based on the criteria set by the user. The sample analysis may indicate that expected performance is not reached for a sample identified as an outlier.
Vision Air is Metrohm’s universal software for Vis-NIR spectroscopy. Vision Air accounts for the unique needs of each type of instrument user. It offers specific interfaces optimized for the most common tasks – simplifying routine measurement, method development, outlier handling, and both data and instrument management. Vision Air is also compatible with third-party software like Unscrambler (Figure 5).
Summary
In the petrochemical industry, typical requirements from management are usually that quality control should be quick, operating costs should be low, feedback should be fast, and operation should be safe.
Typical requirements from the user are that the analysis should be accurate and precise, and the instrumentation should be easy to use, fast, and safe.
NIR spectroscopy is compliant with all of these requirements, and as shown in this blog series, the technology is supported by several ASTM guidelines for method development, method validation, and results validation.
By utilizing NIRS in the petrochemical industry, manufacturers not only improve the efficiency of screening and quality control of petrochemical products, but also fully adhere to internationally accepted standards.
Other installments in this series
This blog article was dedicated to the topic of ASTM norms and how NIR spectroscopy can be used as the ideal QC tool for the petrochemical / refinery industry. Other installments are dedicated to:
