An ISO Guide 34

A brief history of Guide 34

The first edition of ISO Guide 34, released in 1996, addressed the interpretation of ISO/IEC Guide 25 in the area of Reference Material Production (RMP). At the time, Inorganic Ventures was a Guide 25 RMP; accreditation to Guide 34 was not available.

Interpreting Guide 25 as it relates to RMP was a popular and important topic when it first came out. Assessing the competency of reference material producers became increasingly important, and the second edition of ISO Guide 34 was published in 2000 to meet this demand.

Guide 34:2000 outlines all the general requirements that a reference material producer must establish compliance with. A2LA made it available for accreditation. Inorganic Ventures, together with Brammer Standard and Bethlehem Steel, was among the first three organizations to be accredited to Guide 34:2000.

Inorganic Ventures received this accreditation in July 2000, only five months after Guide 34:2000 was made accessible. The 2009/current edition makes these standards mandatory and aligns with ISO/IEC 17025:2005. The third version also involves the production of non-certified reference materials and CRMs.

The development of RMs leaves CRM needs such as material purity characterization, stability evaluation, property value and uncertainty assignment, and metrological traceability to the RMP's discretion.

If you opt to purchase an RM rather than a CRM, consult with your Quality Manager first; otherwise, you may find yourself out of compliance during an audit. The third version requires compliance with the following guides:

• ISO Guide 30, Terms and Definitions used in Connection with Reference Materials
• ISO Guide 31, Reference Materials — Contents of Certificates and Labels
• ISO Guide 35, Reference Materials — General and Statistical Principles for Certification
• ISO/IEC Guide 17025, General Requirements for the Competence of Testing and Calibration Laboratories

ISO Guide 34 - Standards

In analytical chemistry, a true value is a theoretical objective that every RMP and analyst aims for, but can never fully achieve.

A perfect measurement would produce the true value, but since perfection is impossible, the best an RMP can offer is a certified value with an uncertainty designed to contain it.

In other words, it is desirable to create an accurate CRM. Since 1987, when ISO established the ISO 9000 Series Standards, RMPs have only used ISO standards for Quality Management and Assurance.

ISO Guide 34, which particularly addresses CRM creation, has significantly improved the reliability of RMP-produced CRMs. This section is for analysts who have been informed that they must purchase Certified Reference Materials (chemical calibration standards) that correspond to ISO Guide 34.

It is normal to wonder what the distinctions are between Guide 34 CRMs and what they use. Guide 34 CRMs are rapidly becoming a standard requirement for companies engaged in international trade.

The ISO quality standards have considerably reduced the risks of conducting business with unfamiliar international, national, and local enterprises. However, Guide 34 cannot ensure that your analytical measurement will not be incorrect owing to an error in the CRM. The aim of a Guide 34 CRM is to be as close to perfect as humanly possible.

Inorganic Ventures took the following actions and safeguards in accordance with the standards of Guide 34:2009 and its interpretation of them:

• All testing techniques are traceable to the SI. The acronym SI stands for Système International d'Unités (International System of Units).
• Validated methods are used for testing and ensuring accuracy.
• Each test or assay undergoes quality control, CRM analysis, and statistical assessment to ensure appropriate method execution and no changes since validation.
• Multiple testing procedures are employed for CRM-verified stock values whenever they are available.
• Multiple stock samples are collected for CRM certification.
• All CRM batches/lots undergo homogeneity testing before and after packaging.
• All CRMs undergo long-term stability testing.
• CRMs are delivered to harsh temperatures and tested for short-term stability during transportation.
• The uncertainty for each Certified Value is calculated using an error budget that considers characterization, long-term stability, short-term (shipping) stability, and homogeneity.
• Controlled techniques are used to select, test, and clean packaging containers that meet product specifications.
• Quality critical volume measuring equipment, including pipettes, burettes, and volumetric flasks, are identified, calibrated, verified, and maintained in accordance with Class A standards.
• The temperature in all quality-critical laboratory areas is controlled at 20 ± 1 °C. Temperature adjustments are applied to temperature-sensitive measurements.
• Balances are certified, examined, and reported for each use.
• Controlled records cover all aspects of CRM design, manufacturing, storage, delivery, and technical support.
• All materials, chemicals, equipment, and laboratory supplies are sourced from licensed sources.
• ISO Guide 34 RMPs are audited and must comply with the following ISO Guides.
  • ISO Guide 30, terms and definitions used in connection with reference materials,
  • ISO Guide 31, Reference materials—Contents of certificates and labels,
  • ISO Guide 35, Reference materials—General and statistical principles for certification
  • ISO/IEC Guide 98-3, Uncertainty of measurement—Part 3: Guide to the expression of uncertainty in measurement (GUM),
  • ISO/IEC 17025, General requirements for the competence of testing and calibration laboratories.
• CRMs are evaluated for commutability.
  • Post-certification stability monitoring is performed as needed.
• Provide adequate post-distribution services for reference material clients.

ISO Guide 34 - pH buffers

Inorganic Ventures manufactures a wide variety of ISO Guide 34 pH buffers ranging from 1.68 to 12.45 pH units. Custom pH CRMs are also available on request. NIST produces primary pH standards (PS), ensuring traceability to the International System of Units (SI).

All of IV's pH buffers are directly measured against NIST standards, and the pH measurements are carried out using the following cell. Reference electrode: KCl solution (pH (NIST STD) or unknown) | glass electrode.

The uncertainty of pH standards provided by a commercial RMP should be carefully considered by the analyst.

NIST, a National Meteorology Institute (NMI), uses a Harned Cell to produce a PS with uncertainties of approximately 0.004 pH units. Commercial producers, such as Inorganic Ventures, use a glass electrode with errors of no more than 0.02 pH units.

When using a hydrogen gas electrode, cells used by an NMI do not suffer transference errors, however cells used by commercial RMPs have.

Inorganic Ventures and companies have found that employing a glass electrode can result in an uncertainty of up to 0.02 pH units. These uncertainties provide a realistic, dependable measure you can trust.

ISO Guide 34 - Conductivity buffers

Inorganic Ventures offers stock and customized electrolytic conductivity CRMs ranging from two to 175,000 µmhos/cm. Custom Conductivity CRMs are also available on request. All its electrolytic conductivity CRMs are created using 18 MΩ water and high grade KCl. Electrolytic conductivity CRMs are certified by comparing them directly to NIST SRMs.

The stability of these CRMs has been rigorously assessed, covering factors such as biological growth, evaporation, leaching, surface adsorption, and CO₂ absorption from the air.

Each product's uncertainty encompasses characterisation uncertainty, long-term stability, short-term stability, and homogeneity. Its uncertainties are designed to offer you an accurate and trustworthy amount of uncertainty, as well as values you can trust.

ISO Guide 34 - Evaluating suppliers

Many business, medical, and legal decisions depend on chemical data. This puts additional pressure on the analysts to deliver precise and reliable data to justify a particular judgment, explain an event, prepare for the future, or predict an outcome.

Many companies now require their analysts and suppliers to use certified reference materials (CRMs) manufactured by an ISO Guide 34 authorized reference material producer (RMP).

CRMs are likely to be used in a variety of applications, including calibration of testing equipment, validation of test procedures, and quality control samples. Calibrating, validating, and monitoring the quality of your analytical results are all key steps toward ensuring data correctness.

Inaccurate CRMs produce erroneous data, resulting in poor decisions. The following is a list of factors for potential customers before selecting an RMP supplier:

• Make sure your RMP is accredited. A CRM maker that claims to follow Guide 34 but is not accredited may not suit your company's needs. The RMP's Certificate of Accreditation should include a Certificate number and validation period, which is usually available on the company’s website.
• Ensure you get a Certified Reference Material CRM, not a noncertified Reference Material (RM). The third edition of Guide 34 allows for the production of noncertified Reference Materials. The generation of RMs leaves CRM requirements, such as material purity characterization, stability evaluation, property value and uncertainty assignment, and metrological traceability, to the RMP's discretion. If you opt to buy an RM rather than a CRM, make sure to consult with your Quality Manager first; otherwise, you may find yourself out of compliance during an audit.
• Ensure the CRM you want to buy is included in the Scope of Accreditation. Although an RMP is accredited to Guide 34, this does not imply that all items are created in accordance with CRM criteria. Thus, locating a product on the Scope of Accreditation is crucial. Hopefully, the RMP will make the procedure easier for you. Check a sample certificate of analysis to ensure that your major areas of priority have been addressed to your and your Quality Manager's satisfaction. If you are still unsure after inspecting a sample certificate, request that the actual Certificates of Analysis be supplied for your approval before purchase. This should be available for all stock items. If you have technical doubts concerning the CRM's applicability for the planned purpose, contact RMP. No question is too small when ensuring compliance and accuracy.
• To ensure aqueous atomic spectroscopic CRMs fulfill accuracy criteria, weigh them one month after opening and calculate the percentage rise in concentration at the expiration date. An extended expiration date may end up costing far more than it saves.

ISO Guide 34 - Summary

Accurate calibration, quality control, and validation data are essential to reliable results. Precise test measurement data necessitates accurate CRMs. In support of this fact, ISO published Guide 34, which can be used to assess the competency of reference material makers.

The ISO Guides have been crucial in tearing down international trade barriers, with Guide 34 being a critical component. Reference material producers (RMPs) from all around the world are now evaluated using the same Quality Standards.

In a world where chemical test findings are increasingly used to make business choices, using CRMs manufactured by a Guide 34 RMP is a requirement for doing business.

• Stock ICP-OES single element CRMs
• Stock ICP-MS single element CRMs
• Stock ICP-MS single element isotopic CRMs
• Stock speciation CRMs
• Stock Multielement CRMs for instrument tuning, set-up and calibration with instrument manufacturer cross-referencing
• Stock Multielement CRMs for EPA Methods using ICP-OES and ICP-MS
• Stock Ion Chromatography single anion CRMs at 1000 µg/mL
• Stock Ion Chromatography single cation CRMs at 1000 µg/mL
• Stock multicomponent CRMs for Ion Chromatography including EPA Methods 300.0 and 300.1 (parts A and B)
• Stock Conductivity CRMs ranging from 2 to 175,000 µmhos/cm at 25 °C
• Stock pH CRMs at 1.68, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, and 12 pH units
• Customized CRMs for ICP-OES, ICP-MS, Ion Chromatography, Conductivity and pH

About ESSLAB

ESSLAB (Essex Scientific Laboratory Supplies Limited) is a leading global supplier of analytical consumables for chemical analysis. Founded in 1982, ESSLAB has built a strong reputation in the fields of chromatography, spectroscopy, and electrochemistry. Known for their expertise in precision liquid handling, ESSLAB offers a wide range of high-quality products that go beyond just laboratory instruments.

As a key distributor for some of the world’s top Reference Material producers, ESSLAB provides a full range of Certified Reference Materials (CRMs) — both organic and inorganic. These materials are essential for industries to ensure product quality, meet regulatory standards, and improve processes. ESSLAB’s commitment to quality has earned it a reputation as a "gold standard" supplier, trusted by customers worldwide.

The company is also known for its team of highly skilled specialists, who offer expert advice and customized solutions to help clients meet their specific needs. Whether it's navigating complex technical challenges or choosing the right products, ESSLAB’s team adds significant value to every customer interaction.

In addition to its high-quality products and expertise, ESSLAB provides exceptional logistics support. The company’s IATA-qualified team ensures safe and timely shipping of hazardous materials, following all relevant regulations. With a network of trusted carriers, ESSLAB can deliver products efficiently to customers in the UK, Europe, and the Middle East.

Why choose ESSLAB?

ESSLAB is the preferred choice for laboratories and scientific organizations for several reasons:

• IATA Dangerous Goods Regulations Authorized Shipper: ESSLAB ensures all shipments comply with strict safety standards.
• Flexible Shipping Options: The company partners with specialist freight handlers to provide tailored shipping solutions.
• International Trade Expertise: ESSLAB is accredited by the UK Department for International Trade and has over 20 years of experience in exporting.
• Responsive Customer Service: ESSLAB offers live chat, WhatsApp support, and priority response to inquiries.
• Accredited Quality Management: ESSLAB holds ISO 9001 (Quality Management) and ISO 14001 (Environmental Management) certifications.
• Large UK Stock Availability: ESSLAB maintains a large stock of chromatography consumables for quick and reliable delivery.

With its focus on customer satisfaction, high-quality products, and efficient service, ESSLAB is proud to be a trusted partner for laboratories, research institutions, and industries around the world. Whether you need reference materials, precision instruments, or expert logistics support, ESSLAB has the expertise and service to meet your needs.

Sponsored Content Policy: News-Medical.net publishes articles and related content that may be derived from sources where we have existing commercial relationships, provided such content adds value to the core editorial ethos of News-Medical.Net which is to educate and inform site visitors interested in medical research, science, medical devices and treatments.