{"id":2183,"date":"2021-06-23T14:35:44","date_gmt":"2021-06-23T14:35:44","guid":{"rendered":"https:\/\/www.thermofisher.com\/blog\/analyteguru\/charged-aerosol-detection-inspiring-next-generation-separations\/"},"modified":"2026-08-25T23:31:14","modified_gmt":"2026-08-25T23:31:14","slug":"charged-aerosol-detection-inspiring-next-generation-separations","status":"publish","type":"post","link":"https:\/\/www.thermofisher.com\/blog\/analyteguru\/charged-aerosol-detection-inspiring-next-generation-separations\/","title":{"rendered":"Charged Aerosol Detection (CAD): Inspiring Next-Generation Separations"},"content":{"rendered":"
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*Cue the Star Trek music and Captain James T. Kirk voiceover*<\/strong><\/p>\n

Detectors: the eyes of your HPLC. This is the story of charged aerosol detection. Over 15 years: vastly expanding the scope of liquid separations. Allowing liquid chromatographers to see new compounds, boldly showing you what no chemist has seen before.<\/strong><\/p>\n

*End cue*<\/strong><\/p>\n

\"\"Before the invention of charged aerosol detection, liquid chromatographers used detectors such as refractive index, low wavelength UV absorbance, and evaporative light scattering for quantitative analyses.<\/p>\n

While these HPLC detection methods were useful for analyzing compounds incompatible with higher wavelength absorbance with UV-Vis detectors they were also limited because of low sensitivity and quantitation challenges, which severely impacted method development and prohibited research progression.<\/p>\n

Then in the early 2000s, a group of analytical scientists did what scientists do best. They created a more sensitive and universal detection method, which led to the award-winning invention of charged aerosol detector (CAD).<\/p>\n

History of the CAD<\/strong><\/h3>\n

Used exclusively in liquid-chromatographic separations, charged aerosol detection is a universal technique for quantitative analysis and overcomes the detection sensitivity and analyte versatility issues of other universal approaches.<\/p>\n

The first CAD, the Corona\u00ae CAD\u00ae, was introduced to the scientific community at the Pittsburgh Conference in 2005 and commercially available soon after. The creation of this revolutionary technology resulted from a successful collaboration between TSI<\/a> and ESA Biosciences Inc (now part of Thermo Fisher Scientific<\/a>), a chromatography company specializing in high-sensitivity electrochemical detectors.<\/p>\n

In recognition of its potential, the Corona CAD received both thePittsburgh Conference Silver Pittcon Editor\u2019s Award<\/a>(2005) and the R&D 100 award<\/a> (2005).<\/p>\n

<\/u>Fast forward to 2021, CAD is now an integral part of HPLC and UHPLC analysis driven by the sensitive and near-universal analyte response plus standard free quantitation, thanks to over a decade of continued advancements in the technology.<\/p>\n

Background to ESA Biosciences<\/strong><\/h3>\n

ESA, Inc. was founded in 1968 by a group of graduates from MIT who developed an anodic stripping voltammetry-based instrument to measure minute levels of lead in human blood samples. Lead exposure causes severe changes in brain function and interferes with brain chemistry.<\/p>\n

One approach to study changes in brain chemistry is HPLC with electrochemical detection (HPLC-ECD). Unfortunately, commercially available ECDs, at the time, were unreliable and had considerable downtime due to the need for routine maintenance.<\/p>\n

ESA, Inc. solved this problem by developing a more robust and reliable instrument using their novel \u201ccoulometric<\/a>\u201d sensor. Research into novel HPLC-based detectors continued, where they later formed ESA Biosciences and introduced the Corona CAD in 2005.<\/p>\n

ESA Biosciences, Inc.\u2019s first two CADs were strictly designed for HPLC methods and were compatible with any HPLC system. ESA Biosciences Inc was then acquired by Dionex and CADs were redesigned to be integrated into the Thermo Scientific UltiMate 3000 HPLC and UHPLC systems. This integration allowed for more ease of use with the seamlessly integrated system with components designed to fit and work together.<\/p>\n

Thermo Fisher Scientific went on to develop the Thermo Scientific Vanquish LC platform.<\/p>\n

A timeline of CAD evolution<\/strong><\/h3>\n

Like all great inventions, design changes over the years improved detector performance and the overall user experience. The stepwise evolution of this technology dramatically transformed the CAD from a research and development tool to an established quality control detector.<\/p>\n

\"\"<\/span>Table 1. Timeline of CAD evolution.<\/p>\n

Thermo Fisher Scientific\u2019s contribution to advancing CAD <\/strong><\/h3>\n

By far, the most impactful technology advancement happened in 2013 when the CAD was fully redesigned and introduced by Thermo Fisher Scientific as the Thermo Scientific, and later the Thermo Scientific Vanquish Charged Aerosol Detectors.<\/a><\/p>\n

These major redesigns markedly improved the CAD performance and user-friendliness in a few ways:<\/p>\n