Liquid Nitrogen Level When Using Isothermal Jackets

When isothermal jackets are used, it is important not to overfill the liquid nitrogen in the Dewar. At the start of an analysis, the liquid nitrogen level should be no higher than 1/4 in. (0.64 cm) from the top of the isothermal jacket. Overfilling overrides the function of the isothermal jacket and prevents effective control […]

Can I Calculate Density From Free Space

A frequent question is often posed by users, can density be calculated from free space measured on a gas adsorption analyzer instead of using an instrument that is designed to obtain density? This tech note will explore the possibility of using such a method and compare with results obtained by the Micromeritics AccuPyc II. Gas […]

Expanding the Material Characterization “Toolbox” for Excipient and Active Pharmaceutical Ingredient (API) Vendor Qualification

Physical characterization of pharmaceutical excipients is not only a requirement but can also provide data that can be predictive in nature regarding the performance of final dosage forms including tablets, capsules, inhaled dosage forms, transdermals, and others. Manufacturers generally provide some of this physical testing data, such as particle size. In the case of particle […]

Degas Backfill Gas Selection for Micromeritics Gas Adsorption Instruments

Introduction Specific surface areas and pore volume distributions are often determined using gas adsorption techniques. Prior to analysis, any adsorbed gas or vapor phase (such as water or other volatiles) should be removed from the sample. This process is often referred to as degassing the sample. Degassing usually involves either heating the sample or flowing […]

Measuring the Isosteric Heat of Adsorption of CO2 on Micro-Porous Carbons

This application note details the method for obtaining the isosteric heat of adsorption of CO2 on a range of adsorbent grade activated carbons. CO2 adsorption isotherms below saturation vapor pressure were collected using a Micromeritics® 3Flex Surface Analyzer equipped with an iso-controller unit for temperature control. Isosteric heat of adsorption is calculated across the fullest […]

Calculating Free Space with Micromeritics Static (Manometric) Adsorption Instruments

Introduction Specific Surface Area and the Pore Volume Distribution of materials are frequently determined from the adsorption isotherm, which is the quantity of gas that is adsorbed onto the surface and within the pores of a material as a function of pressure above the sample. These analyses are frequently conducted at cryogenic temperatures to enhance […]

Characterization of Carbons Using a Micromeritics 3Flex

Dr. Darren Lapham, MCA Services, Cambridgeshire, UK. This application note describes the analysis of full gas adsorption / desorption isotherms of carbon black samples using a Micromeritics 3Flex micropore instrument. From the isotherms, BET surface area together with micro-pore, meso-pore and small macro-pore size distributions can be ascertained along with pore volume and pore area. […]

Adding a Custom Model to the NLDFT Library – A CO2 GCMC Model for Carbons

New models for determining the pore volume and pore size distribution of porous solids may be easily added to MicroActive™. These kernels developed using NLDFT, GCMC and other variants have been available for more than 20 years. Traditionally instrument manufacturers have supplied these proprietary models. To introduce new powerful capabilities for users, Micromeritics has developed […]

Characterization of Medicinal Tablet Surface Area with the Gemini Series

Gas adsorption surface area values can predict the reaction rate of compounds such as medicinal products in tablet or powder form. The dissolution rates of these products are directly related to the magnitude of their surface areas. Tablets and powders generally have low gas adsorption surface area values. The Materials Analysis Lab (MAL) at Micromeritics […]

Sample Preparation for Breakthrough Analysis

Introduction Breakthrough analysis is a powerful technique for determining the adsorption capacity of adsorbent materials under flow conditions. Breakthrough analysis allows users to more closely mimic process conditions than what can be achieved through static adsorption measurements. Additionally, it allows for easy multicomponent measurements when utilizing a mass spectrometer to determine the outlet species from […]