Analysis of Cholesterol Overload in the Cerebral Cortex of Alzheimer Disease Patients by Secondary Ion Mass Spectrometry (SIMS) (CAT#: STEM-ST-1723-CJ)

Secondary Ion Mass Spectrometry (SIMS) is a technique used to analyze the composition of solid surfaces and thin films by sputtering the surface of the specimen with a focused primary ion beam and collecting and analyzing ejected secondary ions. The mass/charge ratios of these secondary ions are measured with a mass spectrometer to determine the elemental, isotopic, or molecular composition of the surface to a depth of 1 to 2 nm.

Biochemistry; Biomedicine

1. Sample preparation: The sample is prepared by cleaning it to remove any contaminants that could interfere with the analysis. The sample may also be coated with a thin layer of conductive material to prevent charging during analysis.
2. Primary ion bombardment: The sample is bombarded with a beam of high-energy primary ions, typically from an ion gun. The primary ions interact with the atoms on the surface of the sample, causing the ejection of secondary ions, neutrals, and electrons.
3. Secondary ion extraction: The secondary ions are extracted from the sample surface using a high voltage electric field. The extracted ions are accelerated towards the mass spectrometer.
4.Mass separation: The ions are separated by their mass-to-charge ratio (m/z) using a mass spectrometer. The ions are then detected by an ion detector, which measures their abundance.
5. Data analysis: The data is analyzed to determine the elemental and isotopic composition, as well as the chemical structure and molecular fragmentation patterns of the sample. This information can be used to identify the material and understand its properties and behavior.

• Sample: Solid thin layer; Flat surface material; Powder; Metals; Semiconductors and Insulators & More
• Equipment: Dynamic Secondary Ion Mass Spectrometry (D-SIMS) instruments

1. Due to the large variation in ionization probabilities among elements sputtered from different materials, comparison against well-calibrated standards is necessary to achieve accurate quantitative results.
2. SIMS is the most sensitive surface analysis technique, with elemental detection limits ranging from parts per million to parts per billion.