Frederick trained as an apothecary in Germany before coming to London in 1793 and where threw himself into the scientific scene. He established himself as freelance researcher, lecturer and purveyor of chemical equipment. He worked on various projects, for example experiments with gas lighting, and, for a time, he was employed as Humphry Davy’s assistant.
In 1820 he published, A Treatise on Adulterations of Food and Culinary Poisons, which explained that much of the food and drink being sold was not what it claimed to be. The book sold out very quickly. Some of the practices revealed were fraudulent, e.g. selling roasted peas and beans as coffee, while others were downright dangerous, e.g. the use of poisonous chemicals, such as lead, copper and mercury, to enhance the colour wine and sweets. As well as describing the problem and explaining how to test for adulterants, the brave (of foolhardy) Frederick published the names and addresses of traders convicted of adulteration. This made him some powerful enemies and, probably, lead to his public disgrace.
Shortly after the publication of his book Frederick was accused of vandalising books from Royal Institution’s library. This might have been a set up but he was found guilty and in 1821 he fled to Germany where he worked as a teacher.