Tracer Substances for SVC Analysis

Abstract

The present invention relates to novel tracer substances useful in the analysis for semi-volatile organic contaminants (SVCs) such as PCBs (polychlorinated biphenyls). The invention also describes methods for establishing multilayered sealant barriers towards SVCs, which barriers contain said tracer substances, and methods for assessing the integrity of such barriers.

Claims

1. A compound of Formula I for use as a tracer substance in coating compositions: ##STR00005## wherein R.sub.1 is selected from hydrogen, deuterium, hydroxy, C.sub.1-C.sub.6 alkoxy, trifluoromethoxy, 1,1,1-trifluoroethoxy or 1,1,1-trifluoropropoxy, and R.sub.2 is selected from hydrogen, deuterium, hydroxy, C.sub.1-C.sub.6 alkoxy, trifluoromethoxy, 1,1,1-trifluoroethoxy or 1,1,1-trifluoropropoxy, and R.sub.3 is selected from hydrogen, deuterium, fluorine, C.sub.1-C.sub.6 alkyl, trifluoromethyl or trifluoromethoxy, and R.sub.4 is selected from hydrogen, deuterium, fluorine, C.sub.1-C.sub.6 alkyl, trifluoromethyl or trifluoromethoxy, and wherein the linker group G may be absent or the linker group G is a carbon atom linked to 1 or 2 C.sub.1-C.sub.6 alkyl groups optionally substituted with up to 6 fluorine atoms and/or up to 6 deuterium atoms, and wherein the compound contains at least one deuterium atom and/or one fluorine atom.

2. A compound according to claim 1 which is 4,4-bis(2,2,2-trifluoroethoxy)-1,1-biphenyl and having the following structure: ##STR00006##

3. A compound according to claim 1 which is 2,2-Bis(4-hydroxyphenyl)propane-d.sub.16 and having the following structure: ##STR00007##

4. (canceled)

5. A coating composition comprising the following three components: 1. an epoxysiloxane of formula
R.sub.1Si(OR.sub.2).sub.3 wherein R.sub.1 is a C.sub.5 to C.sub.30 alkyl group containing one or more epoxy groups and R.sub.2 is a C.sub.1 to C.sub.6 alkyl group, and 2. an aminosiloxane of formula
R.sub.3Si(OR.sub.4).sub.3 wherein R.sub.3 is a C.sub.5 to C.sub.30 alkyl group containing one or more amino groups and R.sub.4 is a C.sub.1 to C.sub.6 alkyl group, and 3. a compound of Formula I as defined in claim 1.

6. A process for treating surfaces comprising the steps of: a. forming a first barrier over a surface, the first barrier comprising a first coating composition and a compound of Formula I as defined in a claim 1, and b. once the first barrier has cured, forming a second barrier over the first barrier, the second barrier comprising a second coating composition, and c. once the second barrier has cured, forming a third barrier over the second barrier, the third barrier comprising a third coating composition.

7. A process for treating surfaces according to claim 6, wherein the first coating composition is a coating composition comprising the following three components: 1. an epoxysiloxane of formula
R.sub.1Si(OR.sub.2).sub.3 wherein R.sub.1 is a C.sub.5 to C.sub.30 alkyl group containing one or more epoxy groups and R.sub.2 is a C.sub.1 to C.sub.6 alkyl group, and 2. an aminosiloxane of formula
R.sub.3Si(OR.sub.4).sub.3 wherein R.sub.3 is a C.sub.5 to C.sub.30 alkyl group containing one or more amino groups and R.sub.4 is a C.sub.1 to C.sub.6 alkyl group, and 3. the compound of Formula I.

8. A multi-layered barrier covering a surface comprising two or more cured or hardened layers of one or more coating compositions, wherein the first applied layer contains a compound of Formula I as defined in claim 1.

9. A multi-layered barrier according to claim 8, wherein the first applied layer of coating composition is a coating composition comprising the following three components: 1. an epoxysiloxane of formula
R.sub.1Si(OR.sub.2).sub.3 wherein R.sub.1 is a C.sub.5 to C.sub.30 alkyl group containing one or more epoxy groups and R.sub.2 is a C.sub.1 to C.sub.6 alkyl group, and 2. an aminosiloxane of formula
R.sub.3Si(OR.sub.4).sub.3 wherein R.sub.3 is a C.sub.5 to C.sub.30 alkyl group containing one or more amino groups and R.sub.4 is a C.sub.1 to C.sub.6 alkyl group, and 3. the compound of Formula I.

10. A multi-layered barrier according claim 8 comprising at least three cured or hardened layers of one or more coating compositions.

11. A multi-layered barrier according to claim 8 obtainable by the process for treating surfaces comprising the steps of: a. forming a first barrier over a surface, the first barrier comprising a first coating composition and the compound of Formula I, and b. once the first barrier has cured, forming a second barrier over the first barrier, the second barrier comprising a second coating composition, and c. once the second barrier has cured, forming a third barrier over the second barrier, the third barrier comprising a third coating composition.

12. A coating composition kit, comprising the following parts: a. Component 1 admixed with a tracer substance of Formula I according to claim 1 b. Component 1 without tracer substance, c. Component 2, and d. a set of instructions for mixing Component 1 and 2, and for carrying out the surface treating process for treating surfaces comprising the steps of: forming a first barrier over a surface, the first barrier comprising a first coating composition and the compound of Formula I, and once the first barrier has cured, forming a second barrier over the first barrier, the second barrier comprising a second coating composition, and once the second barrier has cured, forming a third barrier over the second barrier, the third barrier comprising a third coating composition, and wherein Component 1 (with and without added tracer substance) and Component 2 of the kit are separate parts.

13. An analytical method for field testing surfaces covered by a multilayered barrier according to claim 8 to determine the co-presence of an semi-volatile contaminant (SVC) and one or more tracer substances of Formula I, using automated test equipment including a gas chromatographic (GC) column connected to a mass spectrometric (MS) detector and a microprocessor including a memory in which is located data regarding magnitudes and retention times for a plurality of standard SVC mixtures and tracer substances, said method comprising the following steps: a. preparing a sample by using a High Volume Sampler (HVS) for SVCs in ambient air, or a standardized wipe sample for surfaces potentially contaminated with SVCs; b. separating and analyzing the components in said sample on a said gas chromatographic column using said MS detector which has an input for receiving said sample and an output for providing separated component peaks; c. providing an electrical output signal including information regarding the magnitude and retention time of component peaks using said mass spectrometric detector which is connected to the output of said GC column; d. comparing said electrical output with the contents of said memory through the use of said microprocessor; and e. indicating one of the following: i. the presence of said SVC in said analytical sample based upon comparison with data in said microprocessor memory, ii. the co-presence of said SVC in said analytical sample together with said one or more tracer substances or, iii. no SVC or tracer substance is present in the analytical sample, wherein the co-presence in the analytical sample of said SVC together with said one or more tracer substances is indicative of cracks or other faults in said multi-layer barrier, whereas the presence of said SVC alone in the analytical sample indicates a new source of the SVC.

14. A coating composition according to claim 5, wherein the compound of Formula I is 4,4-bis(2,2,2-trifluoroethoxy)-1,1-biphenyl.

15. A coating composition according to claim 5, wherein the compound of Formula I is 2,2-Bis(4-hydroxyphenyl)propane-d.sub.16.

16. A process according to claim 6 further comprising applying one or more layers of a primer.

17. A multi-layered barrier according to claim 8, wherein the compound of Formula I is 4,4-bis(2,2,2-trifluoroethoxy)-1,1-biphenyl.

18. A multi-layered barrier according to claim 8, wherein the compound of Formula I is 2,2-Bis(4-hydroxyphenyl)propane-d.sub.16.

19. A coating composition kit according to claim 12, wherein Component 1 comprises an epoxysiloxane of formula R.sub.1Si(OR.sub.2).sub.3, wherein R.sub.1 is a C.sub.5 to C.sub.30 alkyl group containing one or more epoxy groups and R.sub.2 is a C.sub.1 to C.sub.6 alkyl group, and Component 2 comprises an aminosiloxane of formula R.sub.3Si(OR.sub.4).sub.3, wherein R.sub.3 is a C.sub.5 to C.sub.30 alkyl group containing one or more amino groups and R.sub.4 is a C.sub.1 to C.sub.6 alkyl group.

20. An analytical method according to claim 13, wherein the one or more tracer substances of Formula I comprises 4,4-bis(2,2,2-trifluoroethoxy)-1,1-biphenyl.

21. An analytical method according to claim 13, wherein the one or more tracer substances of Formula I comprises 2,2-Bis(4-hydroxyphenyl)propane-d.sub.16.

Description

FIGURES

[0101] FIG. 1: [0102] a) shows a sideway view of a contaminated surface from which a SVC like eg. PCB evaporates (wavy arrows). [0103] b) the same surface as in FIG. 1 a) with a first layer of coating applied, which contains a tracer substance. This layer of coating blocks the evaporation of the SVC. The added tracer substance evaporates from the surface of the first layer of coating (wavy, dotted arrows). [0104] c) the same surface as in FIG. 1 b) with a second layer of coating applied. This layer of coating blocks the evaporation of the tracer substance and provides additional protection against evaporation of the SVC (angular reflected arrows). [0105] d) the same surface as in FIG. 1 c) with a third layer of coating applied. This layer of coating provides additional protection against evaporation of the SVC.

[0106] FIG. 2: [0107] a) shows a sideway view of a surface permeated by a SVC from the surrounding soil, eg radon (wavy arrows). [0108] b) the same surface as in FIG. 2 a) with a first layer of coating applied, which contains a tracer substance. This layer of coating blocks the permeation of the SVC (angular reflected arrows). The added tracer substance evaporates from the surface of the first layer of coating (wavy, dotted arrows). [0109] c) the same surface as in FIG. 2 b) with a second layer of coating applied. This layer of coating blocks the evaporation of the tracer substance and provides additional protection against permeation of the SVC. [0110] d) the same surface as in FIG. 2 c) with a third layer of coating applied. This layer of coating provides additional protection against permeation of the SVC.

[0111] FIG. 3: [0112] a) shows a sideway view of a contaminated surface with three layers of coating applied, including a first layer of coating containing a tracer substance. The resulting barrier is intact, and protects against evaporation of the SVC. [0113] b) the same surface as in FIG. 3 a) wherein cracks have developed in the barrier over time. Both the SVC and the tracer substance evaporate (wavy arrows, both solid and dotted).

[0114] FIG. 4: [0115] General formula for polychlorinated biphenyls.

[0116] FIG. 5: [0117] Three exemplary tracer substance for PCBs: 4,4-bis(2,2,2-trifluoroethoxy)-1,1-biphenyl, 4,4-dimethoxy-1,1-biphenyl-d.sub.6 and biphenyl-d.sub.10

[0118] FIG. 6: [0119] General formula for bisphenols and the specific structure for bisphenol A.

[0120] FIG. 7: [0121] Three exemplary tracer substance for bisphenols: 4,4-(4,4,4-trifluorobutane-2,2-diyl)diphenol; 2,2-bis(4-hydroxyphenyl) propane-d.sub.16 and 2,2-bis(4-hydroxyphenyl) propane-methyl-d.sub.6.

[0122] FIG. 8: [0123] Experimental set-up for example 4.1 with concrete bricks having different areas sealed.

[0124] FIG. 9: [0125] Stainless steelbox with attached sampling tube for air sampling

[0126] FIG. 10: [0127] Graphs showing relation between the available relative area for evaporation and the air concentration of PCBs and the tracer substance 4,4-2,2,2-trifluoroethoxy biphenyl

[0128] FIG. 11: [0129] Experimental set-up for example 4.2 with concrete bricks having different areas sealed.

[0130] FIG. 12: [0131] Experimental set-up for example 4.3 with concrete bricks having different areas sealed.

DETAILED DESCRIPTION OF THE INVENTION

[0132] In a first aspect of the invention a tracer substance is selected from compounds according to the following Formula I:

##STR00002##

wherein
R.sub.1 is selected from hydrogen, deuterium, hydroxy, C.sub.1-C.sub.6 alkoxy, trifluoromethoxy, 1,1,1-trifluoroethoxy or 1,1,1-trifluoropropoxy, and
R.sub.2 is selected from hydrogen, deuterium, hydroxy, C.sub.1-C.sub.6 alkoxy, trifluoromethoxy, 1,1,1-trifluoroethoxy or 1,1,1-trifluoropropoxy, and
R.sub.3 is selected from hydrogen, deuterium, fluorine, C.sub.1-C.sub.6 alkyl, trifluoromethyl or trifluoromethoxy, and
R.sub.4 is selected from hydrogen, deuterium, fluorine, C.sub.1-C.sub.6 alkyl, trifluoromethyl or trifluoromethoxy,
and wherein
the linker group G may be absent, ie the two aromatic rings are directly linked by a single bond, or
the linker group G is a carbon atom linked to 1 or 2 C.sub.1-C.sub.6 alkyl groups optionally substituted with up to 6 fluorine atoms and/or up to 6 deuterium atoms,
and wherein the tracer substance contains at least one deuterium atom and/or one fluorine atom.

[0133] In Formula I the open carbon atom positions are numbered 2 to 6 in the left ring and 2 to 6 in the right ring. The positions 2, 2, 6 and 6 are also called ortho-positions (o-); 3, 3, 5 and 5 are also called meta-positions (m-), and 4 and 4 are called para-positions (p-).

[0134] In a preferred embodiment of the first aspect of the invention the compounds according to Formula I wherein the linker group G is absent, are particularly well-suited as tracer substance for polychlorinated biphenyls (PCBs).

[0135] In a particular embodiment there is provided the use of a compound of Formula I as a tracer substance in sealing compositions for PCB-containing surfaces.

[0136] The following positional isomers are further particularly preferred embodiments of the first aspect of the invention wherein the linker group G is absent:

##STR00003##

[0137] Even though the compounds of Formula I wherein the linker group G is absent are preferably employed as specific tracer substances for PCBs, they can also be used as tracer substance for other natural or man-made contaminants SVCs according to the present invention, such as chlorinated dibenzofurans and benzodioxines having similar diffusion properties and boiling points.

[0138] In a preferred embodiment the compound of Formula 1 contains at least one fluorine atom.

[0139] In another preferred embodiment the compound of Formula 1 contains at least one deuterium atom.

[0140] In another preferred embodiment the compound of Formula 1 contains at least one trifluoromethyl (CF.sub.3), trifluoromethoxy (OCF.sub.3) or trifluoroethoxy (OCH.sub.2CF.sub.3) group.

[0141] In another preferred embodiment the compound of Formula 1 contains at least one trideuteromethyl (CD.sub.3) group.

[0142] In a further preferred embodiment the linker group G is absent, R.sub.3 and R.sub.4 are both hydrogen and R.sub.1 and R.sub.2 are both 1,1,1-trifluoroethoxy placed in the 3, 3, 4 or 4 positions.

[0143] In a particularly preferred embodiment, the compound of Formula 1 is 4,4-bis(2,2,2-trifluoroethoxy)-1,1-biphenyl, ie R.sub.1=R.sub.2=CF.sub.3CH.sub.2O, where R, and R.sub.2 are placed in the 4- and 4-positions of the compound of Formula I, respectively.

[0144] In a particular embodiment there is provided the use of 4,4-bis(2,2,2-trifluoroethoxy)-1,1-biphenyl, ie R.sub.1=R.sub.2=CF.sub.3CH.sub.2O, where R, and R.sub.2 are placed in the 4- and 4-positions of the compound of Formula I, respectively, as a tracer in sealing compositions for PCB-containing surfaces.

[0145] In another preferred embodiment of the first aspect of the invention the compounds according to Formula I wherein the linker group G is a carbon atom linked to 1 or 2 C.sub.1-C.sub.6 alkyl groups optionally substituted with up to 6 fluorine atoms and/or up to 6 deuterium atoms, are particularly well-suited as tracer substances for bisphenols, such as bisphenol A.

[0146] The following positional isomers are further particularly preferred embodiments of the first aspect of the invention wherein the linker group G is a carbon atom linked to 1 or 2 C.sub.1-C.sub.6 alkyl groups optionally substituted with up to 6 fluorine atoms and/or up to 6 deuterium atoms and R.sub.1, R.sub.2, R.sub.3 and R.sub.4 remain defined as above mentioned:

##STR00004##

[0147] Even though the compounds of Formula I wherein the linker group G is a carbon atom linked to 1 or 2 C.sub.1-C.sub.6 alkyl groups optionally substituted with up to 6 fluorine atoms and/or up to 6 deuterium atoms are preferably employed as tracer substance for bisphenols such as bisphenol A, they can also be used as tracer substance for other natural or man-made contaminants SVCs according to the present invention, such as chlorinated dibenzofurans and benzodioxines having similar diffusion properties and boiling points.

[0148] In a further preferred embodiment the compounds of Formula I, wherein the linker group G is a carbon atom linked to 1 or 2 C.sub.1-C.sub.6 alkyl groups optionally substituted with up to 6 fluorine atoms and/or up to 6 deuterium atoms, R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are all hydrogen and the compound of Formula I contain at least one CD.sub.3 and/or at least one CF.sub.3 group, such as one CD.sub.3 group, two CD.sub.3 groups, one CF.sub.3 group, two CF.sub.3 groups, or one CD.sub.3 group and one CF.sub.3 group.

[0149] In a particularly preferred embodiment, the compound of Formula 1 is perdeutero-Bisphenol A, ie. 2,2-Bis(4-hydroxyphenyl)propane-d.sub.16.

[0150] In another particular embodiment there is provided the use of 2,2-Bis(4-hydroxyphenyl)propane-d.sub.16, as a tracer in sealing compositions for Bisphenol A-containing surfaces.

[0151] In yet another embodiment, the compound of Formula 1 is 2,2-Bis(4-hydroxyphenyl)propane-methyl-d.sub.6 (i.e. R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are all hydrogen and G is a carbon atom linked to two CD.sub.3 groups).

[0152] In a second aspect of the invention there is provided a coating composition comprising the following three components: [0153] 1. an epoxysiloxane of formula

R.sub.1Si(OR.sub.2).sub.3 [0154] wherein [0155] R.sub.1=a C.sub.5 to C.sub.30 alkyl group containing one or more epoxy groups, [0156] R.sub.2=a C.sub.1 to C.sub.6 alkyl group, and [0157] 2. an aminosiloxane of formula

R.sub.3Si(OR.sub.4).sub.3 [0158] wherein [0159] R.sub.3=a C.sub.5 to C.sub.30 alkyl group containing one or more amino groups, [0160] R.sub.4=a C.sub.1 to C.sub.6 alkyl group, and [0161] 3. a compound of Formula I according to the first aspect of the present invention.

[0162] In a particular embodiment of the second aspect of the invention, the coating composition contains two or more compounds of Formula I according to the first aspect of the present invention.

[0163] In a third aspect of the invention there is provided a process for treating surfaces comprising the steps of: [0164] a. optionally applying one or more layers of a primer; [0165] b. forming a first barrier over a surface, the first barrier comprising a first coating composition, a tracer substance according to the first aspect of the invention, and optionally having a first color; [0166] c. once the first barrier has cured, forming a second barrier over the first barrier, the second barrier comprising a second coating composition, and optionally having a second color, and; [0167] d. once the second barrier has cured, forming a third barrier over the second barrier, the third barrier comprising a third coating composition, and optionally having a third color.

[0168] A coating composition of the present invention should have a high density signifying a dense structure that prevent fast diffusion of compounds through the layer. It should also have a low solubility for the SVC. Materials based on silicates, alumina silicates and/or other mixed metal oxide films containing mixtures of Si, Ti and Zr oxides will have these properties. To ensure a sufficient flexibility of the films, one or more organic compounds should be present in the film. Such compounds will preferentially contain an aromatic or heteroaromatic moiety with two or more reactive organometallic sites capable of linking into the metal oxide network. The curing process can be initiated by the presence of moisture or by photoinitialisers.

[0169] The one or more colors optionally used in the process according to the third aspect of the present invention may be Fluorescent Dyes, such as UV-, IR- or near-IR Fluorescent Dyes.

[0170] In a particular embodiment of the third aspect of the invention there is provided a process for treating surfaces, comprising the steps of: [0171] a. optionally applying one or more layers of a primer to the surface; [0172] b. forming a first barrier over the surface, the first barrier comprising a first coating composition according to the second aspect of the present invention, and optionally having a first color; [0173] c. once the first barrier has cured, forming a second barrier over the first barrier, the second barrier comprising a second coating composition, and optionally having a second color, and [0174] d. once the second barrier has cured, forming a third barrier over the second barrier, the third barrier comprising a third coating composition, and optionally having a third color,
wherein the second and third barriers do not contain a tracer substance according to the present invention, and may be formed using any suitable curing coating composition compatible with the silicate-based coating composition according to the second aspect of the present invention.

[0175] Surfaces to be treated according to the third aspect of the invention comprise both porous and non-porous surfaces. Examples of porous surfaces comprise concrete (medium to high porosity), brick (very high porosity), and examples of non-porous surfaces comprise wood (low porosity) and painted surfaces (very low porosity). For porous surfaces it is recommended to apply one or more layers of a primer before the first layer of a coating composition.

[0176] In a fourth aspect there is provided a multi-layered barrier covering a surface comprising two or more cured or hardened layers of one or more coating compositions, wherein the first applied layer of coating composition contains a tracer substance according to the first aspect of the invention. A multi-layered barrier according to the fourth aspect will typically have a thickness of between 250-300 m, including the first applied layer of coating composition containing a tracer substance.

[0177] In a preferred embodiment the multi-layered barrier according to the fourth aspect of the present invention comprises a cured layer of coating composition according to the second aspect of the invention.

[0178] As each layer of a multi-layered barrier according to the present invention may be prepared by a number of different application methods, eg by brush or spray, and as the nature and porosity of the surface to be coated will influence the exact thickness of each layer and the interaction between the applied layers, it is not meaningful to describe the multi-layered barrier according to the present invention in terms of absolute measurements of coat thickness etc., but rather as a result of following the instructions according to the third aspect of the invention.

[0179] Therefore, in another embodiment the multi-layered barrier according to the fourth aspect of the present invention is obtainable by the process described in the third aspect of the invention.

[0180] In a fifth aspect of the invention there is provided a coating composition kit, comprising the following parts: [0181] a. Component 1 admixed with one or more tracer substances according to the first aspect of the invention, [0182] b. Component 1 without tracer substance, [0183] c. Component 2, and [0184] d. A set of instructions for mixing Component 1 and 2, and for carrying out the surface treating process according to the second aspect of the invention

[0185] Component 1 (with and without added tracer substance) and Component 2 of the kit are separate parts, and may for example be held in separate storage containers such as bottles or canisters. The kit according to the fifth aspect may also contain the one or more tracer substances admixed with Component 2 instead of Component 1.

[0186] The kit according to the fifth aspect may also contain the tracer substance as a separate part, i.e. not admixed with either Component 1 or Component 2, for example as a solution in ethanol or another suitable solvent.

[0187] The kit according to the fifth aspect may contain as Component 1: [0188] an epoxysiloxane of formula

R.sub.1Si(OR.sub.2).sub.3 [0189] wherein [0190] R.sub.1=a C.sub.5 to C.sub.30 alkyl group containing one or more epoxy groups, [0191] R.sub.2=a C.sub.1 to C.sub.6 alkyl group,

and as Component 2:

[0192] an aminosiloxane of formula

R.sub.3Si(OR.sub.4).sub.3 [0193] wherein [0194] R.sub.3=a C.sub.5 to C.sub.30 alkyl group containing one or more amino groups, [0195] R.sub.4=a C.sub.1 to C.sub.6 alkyl group,
and additionally: [0196] one or more tracer substances according to the first aspect of the invention, optionally as a solution in ethanol or another suitable solvent, [0197] A set of instructions: [0198] For applying the one or more tracer substances to the surface to be treated, [0199] for mixing Component 1 and 2, and [0200] for carrying out the surface treating process according to the second aspect of the invention

[0201] In a sixth aspect there is provided an analytical method for field testing surfaces covered by a multi-layered barrier according to the fourth aspect of the present invention, in order to determine the co-presence of an SVC (such as a PCB) and a tracer substance according to the first aspect of the invention, using automated test equipment including a suitable gas chromatographic (GC) column connected to a mass spectrometric (MS) detector and a microprocessor including a memory in which is located data regarding magnitudes and retention times for a plurality of standard SVC mixtures and tracer substances, said method comprising the following steps: [0202] a. preparing a sample by using a High Volume Sampler (HVS) for SVCs in ambient air, or a standardized wipe sample for surfaces potentially contaminated with SVCs; [0203] b. separating and analyzing the components in said sample on a said gas chromatographic column using said MS detector which has an input for receiving said sample and an output for providing separated component peaks; [0204] c. providing an electrical output signal including information regarding the magnitude and retention time of component peaks using said mass spectrometric detector which is connected to the output of said GC column; [0205] d. comparing said electrical output with the contents of said memory through the use of said microprocessor; and [0206] e. indicating one of the following: [0207] i. the presence of said SVC in said analytical sample based upon comparison with data in said microprocessor memory, [0208] ii. the co-presence of said SVC in said analytical sample together with said tracer substance or, [0209] iii. no SVC or tracer is present in the analytical sample,
wherein the co-presence of an SVC together with the tracer substance (option e-ii) is indicative of cracks or other faults in said multi-layer barrier, whereas the presence of an SVC alone indicates a new source of the SVC.

EXAMPLES

Example 1: Tracer Substances

Example 1a

[0210] 4,4-bis(2,2,2-trifluoroethoxy)-1,1-biphenyl was prepared analogously to 1,4-bis(2,2,2-trifluoroethoxy)-benzene (Reference: A K Ray et al. U.S. Pat. No. 6,458,957 B1, Example 1), starting from 20 gr (65 mmol) 4,4-dibromo-1,1-biphenyl (CAS 92-86-4) instead of 1,4-dibromobenzene.

[0211] Yield: quantitative, mp. 115 C. (ethanol), bp. app. 367 C.

[0212] Analysis: .sup.1H NMR (400 MHz, CDCl.sub.3, tetramethylsilane int. ref) 4.38 ppm 4H q (OCH.sub.2CF.sub.3), 7.0 ppm 4H d (aromatic protons in 3, 3, 5 and 5 position), 7.5 ppm 4H d (aromatic protons in 2, 2, 6 and 6 positions).

[0213] Mass spectrometry: m/z=350, 267 (100%), 239, 156, 128.

Example 1b

[0214] 4,4-dimethoxy-1,1-biphenyl-d.sub.6, is prepared from 4,4-dihydroxy-1,1-biphenyl (CAS 92-88-6) by alkylation with methyl iodide-d3.

Example 1c

2,2-Bis(4-hydroxyphenyl)propane-methyl-d.SUB.6 .(Bisphenol A-(dimethyl-d.SUB.6.))

[0215] The target compound can be synthesized by condensation of hexadeutero acetone and phenol under acidic conditions, and is also commercially available (CAS 86588-58-1).

Example 1d

4,4-(4,4,4-trifluorobutane-2,2-diyl)diphenol

[0216] The target compound is synthesized by condensation of 4,4,4-trifluorobutan-2-one (CAS 2366-70-3) and phenol under acidic conditions.

Example 1e

Bisphenol A-d.SUB.16 .(2,2-Bis(4-hydroxyphenyl)propane-d.SUB.16.)

[0217] Commercially available (CAS Number 96210-87-6)

Example 2: Use of Sealing Compositions Comprising Tracer Substances

[0218] The surface to be sealed should be dry and free of dust. Surfaces which are very smooth or slippery can advantageously be roughened lightly with sanding paper or the like before applying the coating composition, to ensure a good adherence.

[0219] A typical sealant according to the present invention is a two-component silicate based coating composition, comprising an epoxysiloxane component and an aminosiloxane component. The two components are mixed shortly before the application to the surface.

[0220] For the first layer of coating composition to be applied, a relevant tracer substance according to the present invention is either added to the final mixture, or is present in one of the two components before mixing. Alternatively, the tracer substance may be applied neat or as a solution in a suitable solvent like eg. ethanol or cyclohexane/acetone 1:1 before the first layer of coating composition is applied to the surface.

[0221] For porous surfaces it is recommended to apply one or more layers of a suitable primer before applying the first layer of the coating composition.

[0222] The application of the coating composition can be performed using a paint brush, paint roll or by spraying the coating composition onto the intended surface. It is important that fresh paint tools are employed after applying the first layer in order to prevent small amounts of tracer substance to be added to the second and subsequent layers of coating composition.

[0223] Typically at least two layers of coating composition are applied, and normally three layers. The first layer to be applied contains a suitable amount of tracer compound, typically between 25-1000 ppm. The second (and subsequent) layer contains no tracer compound.

[0224] The first layer of coating composition containing the tracer substance is allowed to cure for about an hour, or until the surface is only slightly sticky. The second layer of coating composition is then applied (containing no tracer), and after another curing period of about an hour, a third layer of coating composition may be applied. Additional layers may be applied.

[0225] The resulting multilayer barrier is allowed to fully cure (about 24 hrs at 12 C.) before any further work is performed on the surface.

Example 3: Test for Integrity of the Multilayer Barrier

[0226] The first tests for the presence of SVCs are performed 1 month after the application of the sealant, as described above, to avoid re-volatization from secondary and tertiary surfaces.

[0227] Due to the low concentrations of SVCs in ambient air, large air volumes must be collected. Air volumes of about 1000-2000 m.sup.3 are frequently used, with typical flow rates of 25 m.sup.3/h. A High Volume Sampler (HVS), equipped with a glass-fibre filter for the collection of particulates and a polyurethane foam (PUF) adsorbent for sampling the semi-volatile compounds in the vapour phase, is the most suitable technique for the sampling of SVCs. The adsorbents commonly used for sampling SVCs in ambient air are PUF and an amberlite polymer XAD-2, which is more effective for trapping the more volatile SVCs.

[0228] As SVC partitioning between the gas phase and the particulate phase may be affected by the duration of the sampling, the total atmospheric concentration (i.e. the sum of the filter-retained and adsorbent-retained compounds) should be reported. A sampling time of 24 hours should give a rough estimate of the gas/particulate partitioning of the SVCs.

[0229] The recommended sampling time for air using an HVS is between 24-48 hours. When only a limited number of samples can be taken within a given time period (for example due to budgetary constraints) it is suggested that one 24 h sample is taken every 5 to 7 days. This would limit the number of samples to be analysed each year to 50-70; thus, seasonal changes may be detectable and it should be possible to calculate a reasonably reliable annual average concentration. Alternatively, the monitoring strategy could be based on short intensive measuring campaigns; for example, two campaigns (summer and winter) could be used to obtain information about the main seasonal changes and also about variations in concentration under different meteorological conditions. When re-volatization is important three campaigns could be considered; for example, one in winter, one in late spring/early summer (May-June) when ambient temperatures increase and one in late summer (August-September) when sea water temperatures reach a maximum.

[0230] Sampling can also be conducted as swab tests. If the surface to be sampled is smooth and impervious (e.g., unpainted metal surfaces), a wipe sample can be collected to determine if the surface is contaminated with SVCs. A standard wipe test uses a 10 cm by 10 cm (or equivalent that equals 100 cm.sup.2) template to outline the sample area and a gauze pad or glass wool that has been saturated with hexane or another suitable solvent like ethanol to collect the sample. The solvent-saturated wipe is used to thoroughly swab the area inside the 100 cm.sup.2 template. Care must be taken to assure proper use of the sampling template, as the sample results will be based on the 100 cm.sup.2 sample area (i.e., g per 100 cm.sup.2).

[0231] SVC analysis is then performed by means of gas chromatography coupled with mass spectrometry (GC/MS) using automated test equipment including a gas chromatographic (GC) column connected to a mass spectrometric (MS) detector and a microprocessor including a memory in which is located data regarding magnitudes and retention times for a plurality of standard SVC mixtures and tracer substances.

[0232] The SVC concentrations in the samples should be adjusted for any losses which may have occurred during analysis, by using internal standards. Field blanks and quality control samples should also be used. The analysis shall include the specific tracer substance as an internal standard.

Example 4: Test of Tracer Compounds Under Simulated Compromised Barrier Conditions

[0233] A number of experiments were carried out with the purpose of 1) demonstrating that a coating composition according to Example 2 of the present invention can withhold both semi-volatile compounds (SVCs) and also compounds which are practically non-volatile, and 2) that tracer compounds according to the present invention behave sufficiently similar to the contaminants in question, such that their presence in an analysis indicate a compromised barrier.

[0234] The conclusion of the various tests was, that a coating composition according to Example 2 of the present invention can withhold both types of contaminants, in this case PCBs and Bisphenol A. The tests also demonstrated that it was possible to find tracer compounds with relevant properties for both contaminants.

[0235] As an example of SVCs, PCBs were tested in evaporation tests using a couple of commercial mixtures of PCB congeners and a standardized air sampling procedure. As an example of a nonvolatile contaminant Bisphenol A was tested, using a swab test procedure.

[0236] The following two compounds were tested for their capacity as tracer substances for the PCBs and Bisphenol A (as mentioned above, the term PCBs cover any of 209 configurations (congeners) of a biphenyl ring with various amounts of chlorine atoms substituted around each ring (2 to 10 possible Cl atoms): [0237] 4,4-bis(2,2,2-trifluoroethoxy)-1,1-biphenyl [0238] 2,2-Bis(4-hydroxyphenyl)propane-d.sub.16 (d-Bisphenol A)

[0239] The boiling point of 4,4-bis(2,2,2-trifluoroethoxy)-1,1-biphenyl is app 367 C. at ambient pressure. d-Bisphenol A has a boiling point of app. 220 C./4 mmHg (for all practical purposes, Bisphenol A and its deuterated analogs are not volatile under the test conditions, and are only tested by a swab procedure).

Reagents Used

PCB Reference Mixtures:

Dutch Seven PCB Mixture (NEN 5734/VPR C.SUB.85-16., LGC Standards),

[0240] PCB mix (certified reference material bcr365, LGC Standards),

PCB202 2,2,3,3,5,5,6,6-Octachlorobiphenyl (13C12, 99%, LGC Standards)

[0241] Aroclor 1248 (certified reference material, 1000 g/mL in isooctane, Sigma Aldrich)

DBOB 4,4-Dibromooctafluorobiphenyl (Sigma Aldrich),

Other Reference Compounds:

Bisphenol A (Sigma Aldrich)

Tracer Compounds:

[0242] 4,4-2,2,2-trifluoroethoxy biphenyl prepared according to Example 1a Bisphenol A-d.sub.16 (Sigma Aldrich)

Example 4.1PCB Analysis by Air Sampling

[0243] The experiment comprises 6 concrete bricks (see FIG. 8). Each brick had one surface treated with 1.1 mL Aroclor 1000 ppm solution and 2 mL of a 1000 ppm solution of the tracer substance 4,4-2,2,2-trifluoroethoxy biphenyl. Subsequently 5 of the bricks were sealed twice with a coating composition according to Example 2, with an interval of 30 minutes between each coat. The sealing was finally allowed to cure for 24 hours. The bricks were then treated according to the legends in FIG. 8.

[0244] Subsequently each brick was placed in a stainless steelbox 303030 cm, see FIG. 9 (cleaned with acetone before use). The boxes were closed with duct tape and left standing for 30 minutes. An air sample was then taken from each box using a sampling tube with PUF/XAD-2/PUF-Sandwich sorbent material, with a flow of 2 L/min for 2 hours. Finally each sampling tube was analysed using the method described in the analytical method section.

[0245] The following individual PCB congeners and their isomers were analysed for:

TABLE-US-00001 Boiling Representative compound Congener # CAS# point ( C.) 2,4,4-Trichlorobiphenyl 28 7012-37-5 337 2,2,5,5-Tetrachlorobiphenyl 52 35693-99-3 360 2,2,4,5,5- 101 37680-73-2 381 Pentachlorobiphenyl 2,3,4,4,5- 118 31508-00-6 381 Pentachlorobiphenyl 2,2,3,4,4,5- 138 35065-28-2 400 Hexachlorbiphenyl 2,2,4,4,5,5- 153 35065-27-1 400 Hexachlorobiphenyl 2,2,3,4,4,5,5- 180 35065-29-3 417 Heptachlorobiphenyl

Analytical Method for PCB Testing (by Air Sampling)

[0246] The sampling tube was transferred to a glass beaker, and 5 ml cyclohexane/acetone (1:1) was added together with an extraction standard 4,4-Dibromooctafluorobiphenyl (DBOB). The beaker was then sonicated for 2 hours. 900 L extract was mixed with 100 L injection standard PCB 202 C.sup.13 and analysed by GC-MS in SIM mode. The concentration of the individual PCB congeners was determined based on peak area. The congener concentrations were finally added up and multiplied by 5 (a calibration factor). The concentration of the tracer substance 4,4-2,2,2-trifluoroethoxy biphenyl was determined directly by peak area.

Results of PCB Analysis by Air Sampling:

[0247]

TABLE-US-00002 Summarized results - PCB and tracer substance* in air Lab PCB conc Tracer conc # Sample in ng/m.sup.3 in ng/m.sup.3 1 Brick 1, sealed 100% 640 N.D. 2 Brick 2, sealed and scratched 710 N.D. 3 Brick 3, sealed, 720 13 25% of sealant removed 4 Brick 4, sealed, 775 17 50% of sealant removed 5 Brick 5, sealed, 3910 118 75% of sealant removed 6 Brick 6, not sealed (reference) 8950 219 *4,4-2,2,2-trifluoroethoxy biphenyl, N.D. not detected

TABLE-US-00003 Detailed PCB results PCB congeners in ng/m3 Lab # 28 52 101 118 138 153 180 7 PCB Factor Total PCB 1 90.0 38.0 N.D. N.D. N.D. N.D. N.D. 128.0 5.0 640 2 101.0 41.0 N.D. N.D. N.D. N.D. N.D. 142.0 5.0 710 3 106.0 38.3 N.D. N.D. N.D. N.D. N.D. 144.0 5.0 720 4 113.0 41.7 N.D. N.D. N.D. N.D. N.D. 155.0 5.0 775 5 383.0 333.0 65.3 N.D. N.D. N.D. N.D. 781.0 5.0 3910 6 775.0 638.0 138.0 178.0 33.2 26.3 N.D. 1790.0 5.0 8950

[0248] The above data have been plotted in the graphs shown in FIG. 10 and demonstrate the relation between the available relative area for evaporation and the measured air concentration of PCBs and the employed tracer substance 4,4-2,2,2-trifluoroethoxy biphenyl. As can be seen from FIG. 10, the graphs for the tracer substance and PCBs have almost identical slope from the point where the available area for evaporation reaches about 50%. This indicates that 4,4-2,2,2-trifluoroethoxy biphenyl is a suitable tracer substance for PCBs.

Example 4.2PCB Analysis by Swab Testing

[0249] The experiment comprises 3 concrete bricks (see FIG. 11). Each brick had one surface treated with a 250 ppm solution of 4,4-2,2,2-trifluoroethoxy biphenyl in 50/50 cyclohexane/acetone and with a 10.000 ppm solution of PCB. Subsequently 2 of the bricks were sealed twice with a coating composition according to Example 2, with an interval of 30 minutes between each coat. The last stone was used as an unsealed reference.

[0250] The sealing was allowed to cure for 24 hours, and the bricks were then treated according to the below table. Finally each brick was wiped with a cloth wetted with ethanol, and the cloth analysed using the method described in the analytical method section.

Analytical Method for Swab Testing of Solid Surfaces

[0251] The solid surface to be tested was wiped with a clean cloth wetted with ethanol, and the cloth transferred to a glass beaker. 40 ml cyclohexane/acetone (1:1) was added together with the extraction standard 4,4-Dibromooctafluorobiphenyl (DBOB). The beaker was then sonicated for 2 hours. 900 L extract was mixed with 100 L injection standard PCB 202 C.sup.13 and the sample was analysed by GC-MS in SIM mode. The concentration of the individual components in the mass spectrum was determined based on peak area.

Results of PCB Analysis by Swab Testing:

[0252]

TABLE-US-00004 Summarized results - PCB and tracer substance* Lab # Sample PCB conc. in g/m.sup.2 Tracer* conc. in g/m.sup.2 Wiped area 1 Brick 1 N.D. N.D. 14 21 cm 2 Brick 2 1070 8.9 14 21 cm, sealant removed from an area of 5.5 5.7 cm 3 Brick 3 13700 159 14 21 cm *4,4-2,2,2-trifluoroethoxy biphenyl, N.D. not detected Detailed PCB results PCB congener (g/m.sup.2) Lab # 28 52 101 118 138 153 180 7PCB Factor Total PCB 1 N.D. N.D. N.D. N.D. N.D. N.D. N.D. 5.0 N.D. 2 160.0 44.7 3.910 3.990 N.D. N.D. N.D. 213.0 5.0 1070 3 2010 585.0 58.9 77.20 N.D. N.D. N.D. 2730 5.0 13700

[0253] The results of testing Brick 1 indicate that the sealing composition according to the present invention can withhold both PCBs and the tracer substance, 4,4-2,2,2-trifluoroethoxy biphenyl as the analytical sample did not register any of these two compounds (Table row Lab#1). The results of testing Brick 2 indicate that applying even a very low amount of tracer substance (250 ppm vs. 10.000 ppm PCBs) is sufficient for a positive identification hereof together with identifying PCB congeners. 4,4-2,2,2-trifluoroethoxy biphenyl can therefore for a range of PCB congeners be used as a tracer substance, the presence of which in an air sample or swab test may indicate a compromised barrier if used in accordance with Example 2.

Example 4.3Bisphenol A Analysis by Swab Testing

[0254] The experiment comprises 2 concrete bricks (see FIG. 12). Each brick had one surface treated with a 250 ppm solution of 4,4-2,2,2-trifluoroethoxy biphenyl in 50/50 cyclohexane/acetone, a 1500 ppm solution of Bisphenol-A and a 1000 ppm solution of d-Bisphenol-A. Subsequently one of the bricks was sealed twice with a coating composition according to Example 2, with an interval of 30 minutes between each coat. The sealing was allowed to cure for 3 days. Each brick was then wiped with a cloth wetted with ethanol, and the cloth was analysed using the method described in the analytical method section.

Analytical Method for Swab Testing of Solid Surfaces

[0255] The same procedure was used as described in Example 4.2

Results of Bisphenol a Analysis by Swab Testing:

[0256]

TABLE-US-00005 Results - Bisphenol-A, Bisphenol-A-d and tracer* by swab test Bisphenol-A Bisphenol-A-d Tracer* substance Sample conc. g/m.sup.2 conc g/m.sup.2 conc. g/m.sup.2 Wiped area Brick 1 N.D. N.D. N.D. 14 21 cm Brick 2 6000 5339 29 14 21 cm *4,4-2,2,2-trifluoroethoxy biphenyl, N.D. not detected

[0257] The results indicate that deuterated Bisphenol A can be used as a tracer substance for Bisphenol A, but also that the structurally unrelated compound 4,4-2,2,2-trifluoroethoxy biphenyl can be used. It appears at a lower concentration in the analysis, but was also applied in a much lower concentration from the outset. As 4,4-2,2,2-trifluoroethoxy biphenyl can also be used as a tracer substance for more volatile contaminants (see above example 4.1), this substance may be used as a generic tracer, the presence of which in an air sample or swab test may indicate a compromised barrier if used in accordance with Example 2. The results of testing Brick 1 further indicate that the sealing composition according to the present invention can withhold both Bisphenol A and the tracer substance, 4,4-2,2,2-trifluoroethoxy biphenyl.

Summary of Example 4

[0258] The tests performed under various simulated compromised barrier conditions with the tracer substances 4,4-2,2,2-trifluoroethoxy biphenyl and Bisphenol A-d.sub.16 indicate that these tracers behave very similar to the relevant SVCs, PCB and Bisphenol A, and that the tracer 4,4-2,2,2-trifluoroethoxy biphenyl can be used for both air sampling and swab testing of solid surfaces.