1132-61-2 Good Buffer Solutions 3-(Cyclohexylamine)-1-Propanesulfonic Acid CAPS Buffer

The buffer capacity and various uses of 3-(cyclohexylamine)-1-propanesulfonic acid CAPS buffer

3-(cyclohexylamine)-1-propanesulfonic acid is abbreviated as CAPS, which is a biological buffer. CAS1135-40-6, its molecular formula is C9H19NO3S, molecular weight is 221.32, it is white crystalline powder.

CAPS white crystalline powder

Brief introduction

Buffer capacity of 3-(cyclohexylamine)-1-propanesulfonic acid buffer solution:

Adding a small amount of strong acid or alkali to the buffer solution will not change the pH value of the solution much, but if the amount of acid and alkali is large, the buffer solution will lose its buffering effect. This shows that its buffer capacity is limited.

The buffer capacity of the buffer solution is related to the concentration of the components that make up the buffer solution. The buffer solution composed of 0.1mol·L-1HAc and 0.1mol·L-1NaAc has a greater buffering capacity than the buffer solutions of 0.01mol·L-1HAc and 0.01mol·L-1NaAc. This point can be confirmed by calculation. But the concentration of the components of the buffer solution should not be too high, otherwise, the effect between ions cannot be ignored.

When the ratio of the two components of the buffer solution is not 1:1, the buffering effect is reduced and the buffering capacity is reduced. When c (salt)/c (acid) is 1:1, the △pH is the smallest and the buffering capacity is large. Whether for acid or alkali, it has a greater buffering effect. The pH value of the buffer solution can be calculated by the following formula:

At this time, the buffer capacity is large. The farther the ratio of the buffering components is from 1:1, the smaller the buffering capacity, and it may not even play a buffering role. For any buffer system, there is an effective buffer range, which is roughly within one pH unit on each side of pKaφ (or pKbφ).

Weak acid and its salt (weak acid and its conjugate base) system pH=pKaφ±1

Weak base and its salt (weak base and its conjugate acid) system pOH=pKbφ±1

For example, the pKaφ of HAc is 4.76, so HAc and NaAc are suitable for preparing a buffer solution with a pH of 3.76 to 5.76, which has a greater buffering effect in this range. The buffering capacity is the largest when preparing the buffer solution with pH=4.76, at this time (c(HAc)/c(NaAc)=1. 3-(cyclohexylamine)-1 propanesulfonic acid has a wide range of uses, 3-cyclohexylaminopropanesulfonic acid Acid (CAPS) is relatively stable in nature, with a pKa value of 10.4 at 25°C and a pH buffer range of 9.7-11.1. It is widely used in biochemical analysis and in vitro diagnostic industries.

CAPS 3-(cyclohexylamine)-1 propanesulfonic acid has a wide range of uses:

CAPS is widely used as a biological buffer: used in biochemical diagnostic kits, DNA/RNA extraction kits and PCR diagnostic kits; used in enzymatic chemistry and HPLC separation of alkaline drugs buffer. When CAPS is used as a biological buffer, it needs better purity. Generally, it needs to be analytically pure. When used in industry, the purity requirement is relatively low, but it must be treated differently for different applications.

CAPS is used in industry: for new coatings and new materials, CAPS is also a raw material for manufacturing welding materials, air-conditioning equipment and manufacturing metal lithium.

Used as analytical reagent, heat exchange carrier, and also used in the pharmaceutical industry. Used for air conditioning, but also for making fireworks; dry batteries and making metal lithium, also used as flux and desiccant.

For the coating industry, it is used as a water-based isohydrogen ester curing agent. The water-based isocyanate curing agent can coexist stably with resins containing active groups (hydroxyl, carboxyl, amine, epoxy, etc.) for a long time at room temperature.