Can silver needles be used for drug testing, and what is the principle of silver needle drug testing

Silver needles cannot be tested for poison.

Among the people, it is widely said that silver can detect drugs. As early as the famous forensic scientist Song Ci in the Song Dynasty, there was a record of using a silver needle to perform an autopsy. However, the poison referred to by the ancients mainly refers to the highly toxic arsenic, that is, arsenic trioxide.

In ancient times, the production technology was backward, resulting in arsenic containing small amounts of sulfur and sulfide. The sulfur contained in it can be in contact with silver, and a chemical reaction can be initiated, causing a black layer of "silver sulfide" to be formed on the surface of the silver needle. Therefore, the silver needle test only detected the sulfur in the arsenic, so the silver needle could not identify the poison, let alone be used as a tool for drug detection.

It is not scientific to use silver needles to test drugs, it is very limited to contain sulfide in contact with silverware, it can play a chemical role, silver needles will be black, some items do not contain poison, but contain a lot of sulfur, on the contrary, some are very toxic items, but do not contain sulfur, such as poisonous weeds, nitrites, pesticides, rat poison, etc., silver needles and they are in contact, and there will be no black reaction. Therefore, silver needles cannot identify poisons, let alone be used as a tool for drug testing.

Ancient arsenic was often accompanied by a small amount of impurities such as sulfur or sulfide. Sulfur or sulfide has a certain corrosiveness to silver, and a chemical reaction will occur after touching the silver needle, resulting in the formation of a layer of black silver scale (scientific name: silver sulfide film) on the surface of the silver needle.

This is the principle of the "silver needle drug test" in the TV series.

Silver can't detect all poisons, but it can disinfect:

Silver ions have been shown to have a certain bactericidal effect, and as little as 1 milligram of silver ions per liter of water can kill most bacteria in water. The principle is that silver can form positively charged ions in water, which can adsorb bacteria in water and gradually enter the bacteria, so that its catalyst-amidium system is closed and inactivated, so that the bacteria lose their metabolic ability and die. The use of silver tableware and silver jewelry in daily life may be beneficial to human health to a certain extent.

What is the principle of the "silver needle drug test" in the TV series? It turns out that we have been deceived for so many years.

Yes, silver needles turn black when they encounter drugs.

In fact, the silver needle test does not react with the poison, but with the sulfide in the poison. Realgar (AS2S2) and orpiment (AS2S3), after they encounter the silver needle, they will form a black oxide on the surface of the silver needle - silver sulfide (AG2S), which is based on this principle, so there is a silver needle test poison test.

The world is made up of matter, and there are two main forms of change: chemical change and physical change.

Different from particle physics and nuclear physics, which study smaller scales, the material structure of atoms, molecules, and ions (clusters) studied in chemistry interact with chemical bonds and intermolecular forces, and the scale in which they are located is the closest to the macrocosm in the microscopic world, so their natural laws are also most closely related to the physical and chemical properties of substances and materials in the macrocosm of human existence.