JPH0752188B2 - Alkaloid analysis method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for analyzing an alkaloid having a hydroxyl group. More specifically, it relates to an analytical method for selectively and highly sensitively separating and quantifying the above-mentioned alkaloids in a silylated solution by using direct gas chromatography.

(B) Conventional Technology In general, analysis of amine compounds is important in analysis of biological samples, pharmaceutical analysis, etc., and analysis by gas chromatography has been conventionally performed. In this case, a low molecular weight amine compound having no hydroxyl group can be directly introduced into a gas chromatograph (hereinafter referred to as GC) for separation and analysis, but an amine compound having a hydroxyl group can be adsorbed on a column or the like. It tends to occur and lacks quantitativeness, so its hydroxyl groups have been previously silylated, especially trimethylsilyl (hereinafter TM
It was common practice to write it as S) and attach it to the GC. It is also known that when a high molecular weight amine compound having a hydroxyl group is analyzed by GC, silylating the hydroxyl group also prevents decomposition of the compound at high temperature for gasification. .

On the other hand, in the case of separating and quantifying silylated amine compounds by GC as described above, the detector used is a thermal ionization detector (hereinafter referred to as FTD), which is known to have a high sensitivity for nitrogen compounds. It was being done.

(C) Problems to be solved by the invention However, when the TMS-forming amine compound is directly introduced into the GC using the FTD as it is as the TMS-forming reaction mixture and detection is continued, the Si component in the TMS-forming agent is detected. It has a drawback that it adheres to the alkali metal salt of FTD as a combustion residue and the sensitivity of FTD itself becomes poor. Therefore, in the FTD-based GC, the TMS agent removed from the sample solution must be introduced, but the TMS agent usually used has a high boiling point and is difficult to remove. Even if the TMS agent can be removed, the operation is complicated and takes a very long time. From the above, when analyzing a sample containing a silylating agent by GC
The method using FTD has a problem that accurate quantification and continuous analysis cannot be performed.

As a result of intensive studies in view of the above circumstances, the present inventors have discovered a method for rapidly and selectively separating and quantifying a hydroxyl group-containing alkaloid by GC with high sensitivity.

(D) Means and Actions for Solving Problems Thus, according to the present invention, a sample of an alkaloid having a hydroxyl group is treated with a silylating agent to mask the hydroxyl group of the alkaloid in advance, and then the reaction solution is directly gasified. Emission of cations by subjecting the separated gas to chromatography on the hot metal surface of a heated electrode made of heated metallic platinum, molybdenum, rhenium or iridium or oxides of these metals or mixtures thereof. Then, the emitted cations are captured by the collector electrode, and the captured cations are measured as an ion current by an electrometer to provide a qualitative and quantitative analysis method for an alkaloid.

The alkaloids to be analyzed in the present invention are those having a hydroxyl group such as scopolamine and atropine, and the present invention is a suitable method for easily and highly quantitatively analyzing these alkaloids.

The silylating agent is reacted with the alkaloid under anhydrous condition and under moisture proof, and it is preferable to use an excess of the silylating agent so that the hydroxyl groups are sufficiently silylated. This reaction can be carried out under reaction conditions known per se. Suitably, the silylating agent is a TMS agent. Bistrimethylsilylacetamide and the like are preferable as the TMS agent.

The detector used in the method of the present invention uses a so-called surface ionization method in which a sample gas is incident on a high temperature metal surface to emit positive ions. It is equipped with a collector electrode for trapping ions, an electrometer for measuring trapped cations as an ion current, and a nozzle electrode.

A nozzle electrode is attached to the tip of the sample gas outlet of the separation column, a heating electrode is provided so as to face the nozzle electrode, and a cylindrical collector electrode is arranged so as to surround the electrode.

The heating electrode has a large work function, and is made of a stable metal and / or oxide thereof at a high temperature of 700 to 1000 ° K.
Molybdenum, rhenium, iridium and their oxides are suitable.

In the present invention, a carrier gas is used to carry the sample gas. However, since coexistence of oxygen gas can improve the sensitivity, an oxygen gas supply means may be provided.

An oxygen-containing gas is used as the oxygen gas. The oxygen-containing gas is a gas containing oxygen, and the gas component coexisting with oxygen must be an inert gas. Therefore, oxygen gas, air, etc. are generally used as the oxygen-containing gas. However, hydrogen gas must be avoided. This is because it is possible to detect positive ions while avoiding generation of hydrogen plasma.

In the method according to the invention, the nozzle electrode is connected to the positive side of the high-voltage power supply and a positive DC voltage is applied, so that the collector electrode is negative. On the other hand, the heating electrode is connected to the heating power source.

In the configuration diagram of the detector (1) for amine compounds used in the present invention shown in FIG. 1, the sample gas flowing out from the separation column (2) is introduced from the pipe (5) at the T-joint (3). Is mixed with air. This mixed sample gas is fed from the tip of the quartz nozzle (4) to the ionization chamber (7).
However, the amine compound is ionized to generate positive ions by contacting the heated electrode (15) and thermally decomposing. The positive ions are captured by the collector electrode (11) and amplified by the electrometer (18) for detection.

(E) Examples The present invention will be described in detail below with reference to Examples, but the present invention is not limited thereto.

Scopolamine was selected as a sample, and after strictly drying them, bistrimethylsilylacetamide, which is a TMS agent, was added thereto in an excess amount under a moisture-proof condition and reacted at about 80 ° C. for about 20 minutes. After that, 0.8μ of the obtained reaction mixture was injected into a GC using a surface ionization detector (hereinafter referred to as SID) using a platinum coil electrode as a heatable electrode, and the result was measured to obtain the chromatograph shown in FIG. It was The GC measurement conditions were as follows.

GC column: CBPI 12m × 0.53mm id Fused Silica Column temperature: 250 ℃ Carrier gas: He 2ml / min SID temperature: 300 ℃ Split method: Split ratio 10: 1 Gas chromatograph: GC-7A (SID detector ) From the above results, it is shown that the TMS agent and the scopolamine peak of the sample are remarkably separated, and moreover, stable and highly sensitive measurement is possible, and therefore the quantification and reproducibility are good. .

(F) Effect of the Invention In the method of the present invention, a hydrazine machine such as scopolamine, atropine, etc. has a large molecular weight, a high boiling point, and a small amount of alkaloids that are easily decomposed at high temperature can be stably and rapidly increased. It becomes possible to perform quantitative analysis with sensitivity. Further, the same measurement can be performed for a high molecular weight primary or secondary amine compound having no hydroxyl group by hiding the amino group with a suitable silylating agent. This has recently been applied to the rapid detection and quantification of stimulants with a risk of intentionally or unintentionally increasing the dose, that is, amphetamine, metaphetamine, etc., and can make a great contribution to the fields of pharmaceutical analysis and drug management. Is.

[Brief description of drawings]

FIG. 1 is an explanatory view of the main part of a SID for implementing the method of the present invention,
FIG. 2 is a gas chromatogram diagram of a sample liquid containing scopolamine and a TMS agent mixed by the method of the present invention. (5) …… Air supply pipe, (8) …… Nozzle electrode, (9) …… High voltage power supply, (10) …… Air supply port, (11) …… Collector electrode, (12) …… Inner collector electrode , (13) …… Outer collector electrode, (14) …… Insulator, (15) …… Platinum electrode, (16) …… Transformer, (17) …… Power controller, (18) …… Electrometer, ( A) ... Bistrimethylsilylacetamide, (B) ... scopolamine.

Claims (1)

[Claims] 1. A sample of an alkaloid having a hydroxyl group is treated with a silylating agent to mask the hydroxyl group of the alkaloid in advance, and then the reaction solution is directly subjected to gas chromatography to separate the separated gas into a heated metallic form. Of platinum, molybdenum, rhenium or iridium or an oxide of these metals or a mixture thereof, and contacting the hot metal surface of the heating electrode to emit cations, and the emitted cations are captured by the collector electrode, An alkaloid analysis method characterized by qualitative and quantitative analysis by measuring captured cations as an ion current with an electrometer.