GB2352298A

GB2352298A - Method of detecting organic substances on surfaces in humans.

Info

Publication number: GB2352298A
Application number: GB0017994A
Authority: GB
Inventors: Jan Glauder; Hektor Hebert
Original assignee: Clariant GmbH
Current assignee: Clariant Produkte Deutschland GmbH
Priority date: 1999-07-21
Filing date: 2000-07-21
Publication date: 2001-01-24
Also published as: DE19934242A1; GB0017994D0

Abstract

A method of detecting organic substances, in particular raw materials from cosmetic preparations, on skin or hair by means of Time of Flight Secondary Ion Mass Spectrometry (ToF-SIMS). Firstly the untreated surface of skin or hair is measured, then the mass spectra of pure organic substances whose type and amount are to be determined on the surface are recorded. The hair or skin sample treated with a cosmetic preparation containing the organic compound is then measured before and optionally after washing and mass spectra obtained, and the comparison of the typical mass lines shows whether or not the organic substance is present on the skin or hair.

Description

2352298 Clariant GmbH 1999DE428 Dr. KO/sch

Description

Method of detecting organic compounds on surfaces in humans It is known to analyze organic compounds on solid surfaces by means of the ToFSIMS method (Time of Flight Secondary Ion Mass Spectrometry). It has now been found that this method is also suitable for qualitatively and semi-quantitatively detecting organic compounds on surfaces in humans. Using this method, it is possible to detect the type and amount of such organic compounds on surfaces in humans. In particular, the method is suitable for detecting raw materials which are part of cosmetic preparations and are applied in such cosmetic preparations to the surface of humans, i.e. for example to skin, hair or nails. Suitable raw materials of this type are, for example, surfactants, active ingredients, emulsifiers, pearlizing agents, solvents, solubilizers, care substances, quaternary ammonium compounds, dyes, polymers and thickeners.

The invention thus provides a method of detecting organic compounds on surfaces in humans, these organic compounds being identified by means of Time of Flight Secondary Ion Mass Spectrometry (ToF-SIMS method).

In the ToF-SIMS method (Time of Flight Secondary Ion Mass Spectrometry) the surface of a solid sample is bombarded with primary ions. This detaches positive and negative secondary ions from the surface of the sample, and these are then analyzed in a time of flight mass spectrometer. The information depth is 1 to 3 atomic layers. By removing the upper atomic layer (sputtering) it is also possible to carry out analyses in deeper layers. In a typical analytical instrument of this type Ga" ions (typical ionic energies 15 kV or 25 W, ionic currents 60 pA, 600 pA or 2 nA) are used as primary ions. The lateral resolution is < 500 nm, and the largest scanning area is 300 x 300 pm. Mass spectra of positively or negatively charged secondary ions up to a mass of 10,000 can be recorded. From a measured image it is possible to prepare a distribution diagram from each mass, or to create mass spectra from 2 any desired point. The high mass resolution of the time of flight mass spectrometer permits mass separation up to 10-3 mass units, i.e. particles with the same nominal mass (e.g. Si and C21-14) can be readily differentiated.

In detail, the method according to the invention is carried out by firstly measuring the untreated surface, for example skin or hair. Independently thereof, the mass spectra of the pure organic substances whose type and amount is to be detected on the hair and the skin are recorded. Thirdly, the hair or skin sample treated with a cosmetic preparation comprising the organic compound and subsequently optionally washed is measured. Comparison of the typical mass lines shows whether the organic substance, according to the standard measured previously, is still present on the skin or on the hair or not. Optionally the hair or skin may be washed after treatment with the cosmetic preparation and the mass lines then show whether the substance is still present on-the skin or hair or not.

In addition to this purely qualitative detection, this method can also be used for an at least semi-quantitative detection of the residual amount of organic substances which remain on skin or hair after rinsing. The method according to the invention is particularly suitable for detecting any type of ingredients used in the form of cosmetic preparations of all types for the treatment of skin and hair.

Examples

Compounds or products used:

1. C11/C18-Alkyl-CONCH2CH2 - N(CH2COOH)2 - Genagen LAA I "OH2CH20H 2. C12/CI4-N-Methylglucamide (commercial product with a content of about 81 % by weight of glucamide) 3. Shampoo base consisting of 13% by weight of alkyl diglycol ether sulfate, Na salt, 2% by weight of cocamidopropyllbetaine ad 100% by weight of water 3 Procedure Firstly, Genagen LAA, N-methylglucamide and the untreated hair were measured. Genagen LAA (a liquid) was applied to a substrate and dried in air at RT.

N-Methylglucamide (solid) was smeared on the surface of a substrate. The hairs were cut off and attached to a sample holder. Positive and negative mass spectra were recorded from these samples. The spectra were recorded using a primary ion energy of 15kV and a primary ion current of 2 nA. The measured area was 200 PM2 Genagen LAA and N-methylglucamide were each prepared twice in order to see whether the characteristic mass lines for each substance appeared for both preparations. After the starting materials had been measured, the hairs were washed with the shampoo base/water 1:1 (in a beaker) and rinsed under running water (hand-hot). They were then washed either in the shampoo solution containing Genagen LAA or N-methylglucamide, and then likewise rinsed under running water. Preparation was carried out as described above. The measurement parameters were not changed either. The only change was that for some measurements the measured area was reduced to 50 PM2. The two hair samples were each measured at two different points.

Results In order to find typical mass lines for the pures substances Genagen LAA and N-methylglucamide, their spectra were compared with that for the untreated hair.

What is important here is that typical mass lines are not found in the other substance or on the hairs.

Table I lists the typical mass lines for Genagen LAA and Nmethylglucamide. These masses cannot be detected (or detected only with a very low intensity) on the untreated hairs and are therefore highly suitable for identifying the substances.

4 Table 1

Genagen LAA N-Methylglucamide Positive mass lines 226, 309, 389, 491 196,21,378,400,422,428 Negative mass lines 93,224 59,71,212,227,376 The underlined masses 226 for Genagen LAA and 196 for N-methylglucamide are those with the highest intensity, and are therefore to be used as the main identification feature. All the masses together can be used as fingerprint identification. 10 It is important that the typical mass lines (fingerprint) always result when the corresponding substance is present. Since preparations of each of Genagen LAA and N-methylglucamide were measured which produced the same typical mass lines, these are considered to be valid. 15 The typical groups of mass lines as given above measured for pure Genagen LAA and N-methylglucamide were also measured in the case of the measurement of the hair samples treated with the shampoo comprising the abovementioned surfactant in each case. This shows that both substances are present on the surface of the hair.

Claims

CLAIMS:

1. A method of detecting organic compounds on surfaces in humans, which comprises identifying these organic substances 5 by means of Time of Flight Secondary Ion Mass Spectrometry.

2. A method of detecting the presence of an organic compound on a human surface which comprises the step of recording a Time of Flight Secondary Ion Mass Spectrum of a sample of the surface that had been treated with a composition comprising the organic compound.

3. A method of detecting the presence of an organic compound on the surface of a human which comprises the step of recording a Time of Flight Secondary Ion Mass Spectrum of a sample of the surface that had been treated with a composition comprising the organic compound and the step of comparing that spectrum with a Time of Flight Secondary Ion Mass Spectrum of a sample of the compound that is to be detected.

4. A method as claimed in any one of-claims 1, 2 or 3 which comprises the steps of a.) recording a Time of Flight Secondary Ion Mass Spectrum of a sample of the surface, b.) recording a Time of Flight Secondary Ion Mass Spectrum of an organic compound that is to be detected c.) treating a sample of the surface with a composition comprising the organic compound d.) recording a Time of Flight Secondary Ion Mass Spectrum of a sample of the treated surface and e.) comparing the spectra obtained in steps a.), b.) and d.) 6

5. A method as claimed in claim 3 or claim 4 wherein the highest intensity mass line for the organic compound is 5 compared between the spectra.

6. A method as claimed in any one of claims 1 to 5 wherein a plurality of organic compounds are detected in a single operation. 10

7. A method as claimed in any one of claims 4 to 6 wherein the surface is rinsed or washed between steps c.) and d.).

8. A method as claimed in any one of claims 1 to 7 wherein 15 the surface is that of skin or hair.

9. A method as claimed in claim 8 wherein the surface is that of hair.

20.

10. A method as claimed in any one of claims 1 to 9 wherein the compound(s) to be detected is (are) an ingredient(s) in a cosmetic preparation.

11. A method as claimed in claim 10 wherein the cosmetic 25 preparation is a shampoo.

12. A method of detecting the presence of an organic compound on a human surface which comprises the steps of a.) removing a sample of the surface from the human b.) recording a Time of Flight Secondary Ion Mass Spectrum of the sample of the surface, c.) recording a Time of Flight Secondary Ion Mass Spectrum of an organic compound that is to be detected, 7 d.) treating a sample of the surface with a composition comprising the organic compound e.) removing a treated sample of the treated surface from the human f.) recording a Time of Flight Secondary Ion Mass Spectrum of the sample of the treated surface and 9.) comparing the spectra obtained in steps a.), h.) and f.)

13. A method as claimed in claim 12 wherein the surface is rinsed or washed between steps d.) and e.) and/or between steps e.) and f.).

14. A method as claimed in claim 1, claim 2, claim 3 or 15 claim 12 carried out substantially as herein described with reference to the Example.