Chapter 921: Showing One's True Self in Front of Others (Please Vote and Subscribe!!!)

The police found no trace of blood in the bathroom, and the always-tried luminol reagent failed.

Even the detergent was washed away completely.

How much water did the prisoners use?

Sakaki once said that if there is a prisoner who can perfectly remove traces of blood from a crime scene, then he must be a born criminal or a top chemist.

Only prisoners who truly understand how the luminol reagent works can find ways to avoid reagent detection.

"This place must have been scrubbed!"

Conan scratched his hair irritably:

"How come there are no traces?"

"This is the bathroom."

Glancing at him, Sakaki said calmly:

“What better place to clean up traces than in the bathroom?”

"As long as the prisoner wants, he can use tons of water to wash away the blood on the ground."

"The detection amount of the luminol reagent can reach one part per million! There should be traces left!"

Everyone's expressions were ugly. They could roughly guess that the prisoner used some method to completely remove the blood residue, but...

They don't know what method the other party used.

Mere conjecture cannot be used as evidence.

Conan hated this feeling. For the first time, he felt as if he had lost. He had lost at what he was best at. The prisoner was like the night watcher playing with the maze, and he was the little sheep who mistakenly entered the maze, looking around. The walls kept moving violently, trembling, and the whole day was filled with panic.

Unraveling the mystery of the prisoner seems to be an important factor in breaking the situation.

"Two great detectives, please have a word!"

Kyoukichi Ishimoto shouted:

"You have arrested so many criminals, do you think they have to be imprisoned in Hakone?"

Mouri Kogoro lit a cigarette and remained silent. His eyes were hidden in the smoke, as if he wanted to see through the secrets hidden behind the smoke.

As for Sakaki Makoto

Rubbing his eyebrows, he felt a little headache.

To be honest, it is not that he has never encountered powerful prisoners, but a prisoner who can remove traces of blood from the scene does not need to resort to such unbelievable methods as killing people and hanging their bodies, as if he was taking revenge on Naoki Seiichi.

"have no idea"

Just when everyone was helpless, Miss Miyano, who was standing alone, suddenly said in a cold voice:

"Have you ever heard of disodium EDTA?"

"Disodium EDTA?"

Sakaki raised his eyebrows:

"Isn't this an industrial chelating agent?"

"Yes, the chemical formula of disodium EDTA is C10H14N2Na2O8. It is a very important compound used to chelate a variety of metal ions in hard water, including but not limited to calcium, magnesium, iron, lead, iron, and copper ions."

The corners of her mouth raised. This is Miss Miyano's area of ​​expertise. Her talent is not just about developing APTX4869:

"The so-called chelation refers to the coordination ring formation process between two or more coordination atoms in the same ligand and the same central atom, just like the two big claws of a crab clamping food, calcium, Metal ions such as magnesium and iron will be forcibly changed and replaced from their original structure under the action of chelates. "

"What does this have to do with the luminol reagent?"

Ishimoto Kyoukichi said doubtfully:

"Could it be that disodium EDTA can damage the blood structure and avoid detection by the luminol reagent?"

"As long as you use it correctly, it can be done."

Turning on the light in the bathroom, everyone's eyes focused on Miss Miyano. They saw her holding her arms, and an easy-to-understand explanation came from her cherry-red lips:

"Many people only know that luminol reagents can detect traces of blood, and they can still detect traces of blood even after decades, but they don't know the luminescence principle of luminol reagents."

"The luminescence of the luminol reagent originates from oxidation, and human blood contains hemoglobin. Hemoglobin is a special protein that transports oxygen in red blood cells. It is composed of globin and heme. Each heme is composed of 4 pyrrole subunits. Ring, the center of the ring is a ferrous ion, and iron can catalyze the decomposition of hydrogen peroxide (hydrogen peroxide), turning the hydrogen peroxide into water and monooxygen, and the monooxygen makes luminol glow, so..."

"The luminol reagent is essentially detecting the heme left behind at the crime scene."

"oh!"

Patting his thigh, Ishimoto Kyoukichi seemed to understand:

"So the luminol reagent needs to be mixed with luminol solids in hydrogen peroxide and prepared on site, otherwise the chemically unstable hydrogen peroxide will decompose itself over time!"

"That's right."

Nodding, Miss Miyano continued:

"As I said just now, disodium EDTA, as a chelating agent, can chelate a variety of metal ions in hard water, including ferrous ions."

"Following the steps, as long as the prisoner first washes the blood with common 84 disinfectant mixed with water, it can cover traces in a short time and damage DNA and other blood proteins, causing hemoglobin to decompose and produce hemolysis, but the hemoglobin is still there."

"After the hemoglobin is decomposed and the heme is exposed, the ground needs to be washed with a 1:1 concentrated solution of disodium EDTA to chelate all the metal ions in the blood. The overbearing concentrated solution of disodium EDTA will forcefully tear open the heme ring and remove the hemoglobin ring. The ferrous ion that goes to the center.”

"At the end of this step, use a dilute solution of disodium EDTA for a second cleaning to completely remove all residues. Finally, use a large amount of clean water to wash the ground to complete the destruction of evidence."

"Now."

Miss Miyano glanced at everyone:

"Do you understand?"

"I understand, I understand."

For some reason, everyone nodded repeatedly, with cold sweat covering their backs. They couldn't say a single word, and were unilaterally suppressed by the momentum.

this.

Is it the power of knowledge?

"Ahem, that one"

Ishimoto Kyoukichi cleared his throat and bravely stepped forward:

"Miss Haiyuan, where were you between 3 and 4 o'clock this morning?"

".You suspect that I am a prisoner?"

"No no no no."

With his head shaking like a rattle, Ishimoto Kyoukichi denied repeatedly:

"It's just a routine review."

"Between 3 a.m. and 4 a.m., Xiaolan and I stayed in the room and never left."

Miss Miyano smiled contemptuously:

"Also, Mr. Police, you don't think that the prisoner would be stupid enough to reveal his modus operandi, do you?"

"Of course it's impossible, I'm really just doing a routine review!"

Ishimoto Kyoukichi retreated instantly, was defeated, and lost the courage to continue his attacks.

Sakaki suddenly felt someone tapping his arm from both sides, one left and one right, up and down.

Turn around and look.

Kidd and Conan both had expressions of lingering fear, and there was a lot of emotion in their sighs:

"It's really not easy for you. You have such a girlfriend. If you let her down one day, you may die without knowing how."

"Yes, yes."

Conan agreed with deep understanding:

"With her professional knowledge, the Savior is not easy to use."

"You two are here to stir up trouble? Do you like it?"

"Mad, we can't control her, don't harm anyone!!!"

Ps: As a biology and chemistry expert (pseudo), isn’t this worth a ticket?