JPH07118863A - Method for plating carrier - Google Patents

Abstract

PURPOSE:To uniformly carry out electroless plating on a carrier by fixing ions of Pd, Ni, etc., on the carrier with negative charges and subjecting the surface of the carrier to electroless plating. CONSTITUTION:Ions of Pd, Ni, Co or Cu are fixed on a carrier with negative charges. In the case of a carrier with no negative charges, latex prepd. from vinyl ester of acetic acid and acrylic acid is fixed on the carrier and then the ions are fixed. The surface of the carrier with the fixed ions is subjected to electroless plating as usual. Regardless of the carrier, electroless plating is uniformly carried out.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an improved method for electroless plating a carrier.

[0002]

2. Description of the Related Art Today, immunoassays are used in many fields such as clinical examinations. The immunoassay method is roughly divided into the heterogeneous method that requires B / F separation,
It can be divided into a homogeneous method that does not require B / F separation. Although there are various separation methods in the heterogeneous method, B / F separation using a magnetic carrier is often used.

The method of producing a magnetic carrier by electroless plating is
There is US Pat. No. 4,177,253. This method
Inorganic compounds, organic compounds, ceramics, glass, metals,
Electroless plating is carried out using a natural polymer, an artificial polymer or the like as a carrier, but the surface characteristics of the carrier itself are not mentioned. During electroless plating, a palladium chloride solution is applied to the surface of the carrier, and after cleaning, the plating solution is brought into contact with the carrier.Therefore, how to uniformly trap palladium on the surface of the base carrier becomes an important issue. There is.

[0004]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned conventional drawbacks, and an object thereof is to provide a method for uniform electroless plating regardless of the carrier. .

[0005]

The present inventors have arrived at the present invention as a result of extensive studies on the above problems. That is, the present invention, a carrier having a negative charge, palladium ions,
This is a method of plating a carrier, which comprises immobilizing nickel ions, cobalt ions or copper ions and then subjecting the surface to electroless plating. Further, the present invention is a carrier characterized by immobilizing a substance having a negative charge on the surface of the carrier, immobilizing palladium ions, nickel ions, cobalt ions or copper ions thereon, and subjecting the surface to electroless plating. This is the plating method. Hereinafter, the present invention will be described in more detail.

The carrier used in the present invention is not particularly limited and, for example, metal, resin, glass, ceramic, wood, ion exchanger and the like can be used. Further, the size and shape thereof are not particularly limited, and they can be applied to particles, fibers, plates and the like. When the carrier itself has a negative charge, it is possible to proceed to the next step as it is.

However, in the case of a carrier having no negative charge,
A substance having a negative charge must be immobilized on its surface. As such a substance, those which do not have reactivity or interaction with a carrier are preferable, and examples thereof include latexes using vinyl acetate and acrylic acid as raw materials, long-chain fatty acids, or polymers having carboxylic acid as a functional group. can give. The method of immobilization depends on the type of the carrier and the substance having a negative charge, but it is convenient to carry out coating, spraying, dipping and the like and drying.

A substance having a positive charge is immobilized on such a carrier having a negative charge on its surface or itself. Examples of the substance having a positive charge include palladium ion, nickel ion, cobalt ion or copper ion. The immobilization method is not particularly limited,
If it is brought into contact with or applied to the surface of the carrier, it is immobilized by electrostatic action.

Next, electroless plating is applied to the carrier on which the cations are fixed. The method of electroless plating is not particularly limited, and it can be performed by a commonly used method.

[0010]

According to the present invention, the surface of the carrier can be uniformly electroless plated. This is a simple method regardless of the size and shape of the carrier and has the advantage that the formed plating is difficult to remove. The carrier electrolessly plated according to the present invention can be widely used as a carrier for immobilization, not limited to the field of biochemistry such as a carrier for immobilized enzyme and a carrier for immunoassay.

[0011]

【Example】

Example 1 A latex suspension (concentration 5.5%) using vinyl acetate and acrylic acid as raw materials was applied on the surface of an ethylene vinyl acetate copolymer (UP polyethylene-EVA710, diameter 1.2 mm) manufactured by Tosoh Corporation. After drying, it was immersed in a 2.5% palladium chloride solution at 25 ° C. for 4 minutes. The palladium chloride solution was removed and dried. Then, it was immersed in a plating solution having the following composition twice (5 minutes per time).

Composition of plating solution 112 g CoSO ₄ .7H ₂ O 565 g sodium potassium tartrate 330 g ammonium sulfate 2.8 g boric acid 1.3 g sodium hypophosphite was dissolved in water (pH 9.5) to make a total volume of 4 liters.

The third time, it was immersed in the plating solution for 2 hours, and then the carrier was washed to obtain the desired plated carrier.

Example 2 An ion exchanger (IR-120B, average particle diameter 0.5 mm) manufactured by Organo Corporation was added to a 2.5% palladium chloride solution to prepare 25
Immerse at 4 ° C. for 4 minutes. The palladium chloride solution was removed by centrifugation and then dried. Then, it was immersed in a plating solution having the same composition as in Example 1 for 10 minutes. The color of the particles changed from transparent to black, and a plating layer was formed on the surface of the carrier. After washing, the desired plated carrier was obtained.

Example 3 An ion exchanger manufactured by Tosoh Corporation (TSKgelSP-Toyopearl 650, average particle size 50 μm) was immersed in a 2.5% palladium chloride solution at 25 ° C. for 4 minutes. The palladium chloride solution was removed by centrifugation and then dried. Then, it was immersed in a plating solution having the same composition as in Example 1 for 5 minutes.
The color of the particles changed from translucent to black, and a plating layer was formed on the surface of the carrier. After washing, the desired plated carrier was obtained.

Claims (2)

[Claims] 1. A method of plating a carrier, which comprises immobilizing palladium ions, nickel ions, cobalt ions or copper ions on a carrier having a negative charge and then subjecting the surface to electroless plating. 2. A carrier characterized by immobilizing a substance having a negative charge on the surface of the carrier, immobilizing palladium ions, nickel ions, cobalt ions or copper ions thereon, and subjecting the surface to electroless plating. Plating method.