Abstract:
A container used for chromatographic sample analysis has (a) at least one silica uppermost layer, which is deposited onto the container using a liquid phase deposition process, and, optionally, (b) at least one indicator present in at least part of the at least one silica uppermost layer for visually distinguishing the container from other containers, and/or determining the “use status” of the container, and/or identifying the proper orientation of the container when it is to be put in use, and/or providing a means of decoration, identification, or counterfeit detection. In one preferred embodiment, the indicator is thermochromic. In another preferred embodiment, the indicator is photochromic.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    Gas chromatography (GC) is a well known analytical technique where gas phase mixtures are separated into their individual components and subsequently identified. The technique may be employed to obtain both qualitative and quantitative information about the components of the mixture. Specifically, the separation mechanism employs two different media, one moving (mobile phase) and one unmoving (stationary phase). In GC, the mobile phase is normally hydrogen or helium, which flows across the stationary phase, which is a solid or otherwise immobilized liquid on a solid support on the interior capillary wall. 
         [0002]    The sample mixture is introduced into the mobile phase stream and the residence time of each component of the sample in the stationary phase relates to differences in their individual partitioning constants with respect to the two solvent phases. 
         [0003]    Samples for GC are usually liquid and must be volatized prior to introduction to the mobile phase gas stream. GC analysis is typically divided into five stages:
       1. Sample storage, where analytical samples (including standards) are managed prior to insertion to the instrument,   2. sample preparation, where samples are inserted into the instrument, heated, and (if in liquid form) volatilized,   3. sample loading, where the sample vapor is loaded all or in part onto the analytical column,   4. separation, where the sample is separated into its individual components as it passes through the analytical column, and   5. detection, where the separated components are identified as they exit the analytical column.       
 
         [0009]    In conventional GC instrumentation, step 1 usually involves glass vials or containers, often loaded into an autosampler device. In this fashion the autosampler may contain multiple samples in vials slated for analysis. Steps 2 and 3 are achieved in the sample inlet hardware. Inlet hardware often includes a sample injection syringe and a replaceable sleeve, or liner. Liners are normally operated at elevated temperatures, e.g., over 200′C. This enhances the rate of sample vaporization and reduces adsorption on the inner surface of the liner [1]. Many internal configurations are available for liners, as well as coatings for them [2-12]. 
         [0010]    In most cases the configuration of the liner serves to enhance the degree of sample volatilization from the point of exit from the syringe needle to the column entrance, and provide gas phase sample homogeneity from components within the liquid mixture having different boiling points. A simple configuration for an inlet liner is a straight cylindrical tube of glass having a consistent inner diameter along the longitudinal path. Other configurations include more complex inner paths intended to increase turbulence, affect the comparatively short residence time the liquid sample is in the liner, or interrupt the liquid stream leaving the syringe needle. These internal configurations include tapers or goosenecks, baffles, funnels, inverted cup elements, spiral regions, points of flow constriction, and drilled holes along the longitudinal path of the liner. 
         [0011]    Other elements of liners optionally include small plugs of packing materials such as glass wool [1], Carbofrit™ (Trademark of Restek Corporation) packing material, and more recently inert metal wire bundles [13] which serve as additional surface area sources for heat transfer into the sample and as a physical filter for any solid/nonvolatile contaminants present in the liquid sample. 
         [0012]    During the injection process, it is also important to minimize sample/liner and (if applicable) sample/packing material interactions that can result in undesirable chemical reactions, decomposition, or temporary/permanent adsorption of the sample, It is equally important that the liner not contribute contaminants to the analysis, which may result in spurious peaks or an increase in the baseline signal in detection measurements of the components contained in the sample being analyzed. 
         [0013]    In cases where liners become contaminated with solid/nonvolatile species it is necessary to replace them from time to time. Liner replacement frequency depends on the type of sample; with ‘dirty’ samples having high concentrations of high boiling point components or large amounts of nonvolatile particulate matrix shortening the service life of the liner. 
         [0014]    Because of the techniques commonly employed in using a liner in a GC instrument it is often desirable for the liner to be transparent. It is particularly important to be able to see through the walls of these liners which contain packing material in order to ensure its proper plug position within the internal bore of the liner and to be able to check for the presence of debris or other visual contaminants. 
         [0015]    Various chemical coatings are applied to liners in order to reduce the degree of interaction between the sample and the surface of the liner. Sample-surface interactions may result in sample absorption in the coatings, decomposition of the coatings, and formation of new reaction products; in each case resulting in undesirable peaks (or loss of desirable ones) in detection measurements of the components contained in the sample being analyzed in the separation analysis. In addition to low sample-surface interactions, it is also desirable for the liner coating to be thermally stable in order to minimize background signal contributions originating from the liner coating itself detected by the analytical equipment. For glass substrate liners, common deactivation techniques include chemically treating the exposed silanol groups with organosilane reagents such as hexamethyldisilazane (HMDS), dimethyldichlorosilane (DMCS), and trimethylchlorosilane (TMCS) [15]. 
         [0016]    Liners are manufactured from glass, primarily borosilicate, but also fused quartz, and less commonly from metal, mainly stainless steel [16]. 
         [0017]    The chemical composition of a quartz or fused silica liner is commonly 99.4-99.9% silicon dioxide (SiO 2 ). The uppermost surface of the SiO 2  silica contains a uniform, high concentration of silanol (Si—OH) groups. This represents the optimal surface with which to apply the deactivation chemistry described. An even distribution of silanol groups across the silica surface ensures a uniform deactivation coating which creates the most effective sample barrier [1]. 
         [0018]    While quartz is chemically the preferred material to make liners, the high melting point temperature (1650° C.) required to manipulate the cylindrical shape makes quartz practical strictly for straight tube liner designs (See Table 1)[17]. The difficulty in manipulating fused quartz into precision shapes has led to the need for subsequent machining or grinding operations on the stock tubing. While the initially drawn tubing is smooth and free of non-silica defects, these features are lost in subsequent processing. The risks of impurity introduction by machining or grinding, as well as the introduction of scratches and crevices, complicate production of optimal fused quartz liners for GC use. 
         [0019]    Similar limitations are observed for sample vials manufactured from quartz. Quartz vials must be manufactured at temperatures higher than that required for borosilicate glass. Vials manufactured from quartz requires higher temperature furnaces and tooling having higher heat resistance. This greatly increases the costs for quartz vials as compared to those made from borosilicate glass or other glasses having comparatively lower softening points. 
         [0020]    Laboratory borosilicate glass begins to soften at ca. 650° C., which enables comparatively low temperature thermoforming with which to create the complex shapes like those depicted in FIGS.  1  and  2 A- 2 I. Pyrex borosilicate glass includes a relatively high concentration of non-silica moieties (ca.19%) including primarily boron, sodium, aluminum, and potassium. To create a pure silica surface wherein pure is defined as containing at least 90% wt. silica and hydroxylated silica, these contaminating species are generally removed by aqueous acid leaching prior to application of deactivation coatings [1]. The general commercial manufacturing stages for fused silica and borosilicate glass liners are described in  FIGS. 3   a  and  3   b . For the case of borosilicate glass, the surface purity following acid leaching resembles that of virgin fused quartz (or fused silica) with the advantage of the bulk item having the low temperature thermoforming ability of the borosilicate glass substrate. 
         [0021]    Acid leaching of the borosilicate glass article has been shown to leave a roughened silica enriched surface by solubilizing and removing the accessible domains enriched with non-silica components. The surface resembles that of silica gel following this leaching process with superficial pores commonly around 5 nanometers in average diameter, but which may be smaller or much larger for some specialty borosilicate glasses [18-23]. Because of sterile limitations within the thus-formed pores and crevices, a number of silanol groups are unreachable for coverage by the silane deactivation reagent. A lack of coverage completeness of the deactivation coating yields a population of residual active sites capable of interaction with analytes in the finished article. [1] There is a need in the field of gas chromatography for easily formable containers fabricated from glass and with a very low surface area pure silica surface suitable for effective chemical deactivation with traditional reagents. 
         [0022]    In addition to silane treatments, another suitable deactivation coating is vapor deposited hydrogenated amorphous silicon, including the Siltek® Sulfinert® coatings [17, 24-26]. These coatings have been demonstrated on both borosilicate glass and metal surfaces, and in both cases it results in a semi-opaque mirror finish whose color is dependant on the coating thickness. 
         [0023]    While chemically inert to many analytes, the Sulfinert® surface is not represented as being perfectly smooth. The creation of the amorphous hydrogenated silicon first layer takes place through decomposition of silane gas, and a layer of silicon may not completely cover the entire substrate surface after one silicon deposition cycle. The silicon deposition cycle is usually repeated several times to build up the passive layer of silicon to the requisite thickness. [25]. The surface morphology of these coatings has been studied and SEM data shows the presence of a textured surface for Silcosteel®, a related coating [27]. 
       Discussion on Liquid Phase Deposition (LPD) 
       [0024]    Liquid phase deposition of a silica film on glass sheets from fluorosilicic acid solutions under mild conditions was first described by Kawahara [28]. It was developed as an alternative to more costly sputtering and chemical vapor deposition techniques for large objects, and was shown to give a more dense silica coating than that obtained through selective leaching processes. The motivation for this work was to be able to economically alter the light reflecting properties of large glass sheets, as well as reduce alkali metal migration for battery, liquid crystal display, and solar cell applications, as well as to provide an electrically insulating layer for electronic devices. 
         [0025]    The reversible reactions can be exploited to deposit, precipitate, and/or change composition through evaporative or distillative processes depending on choice of conditions. The equilibria of mixtures of fluorosilicic acid and silica have been explored in detail [29-33]. 
         [0000]      H 2 SiF 6 +2H 2 O⇄SiO 2 ↓⇄+6HF
 
         [0000]      5H 2 SiF 6 +SiO 2 ↓⇄3[H 2 SiF 6 .SiF 4 ]+2H 2 O⇄3H 2 SiF 6 SiF 4 ↑+2H 2 O
 
         [0026]    It is clear that several components are present in equilibrium in an aqueous solution of fluorosilicic acid. As these can vary in relative concentration, we refer to any stable, homogeneous liquid reaction product of silica, hydrogen fluoride and water in this invention as fluorosilicic acid. In the event that a change occurs which renders the homogeneous solution unstable with regard towards precipitation of solid silica in any form, the solution shall be referred to as being supersaturated with silica. 
         [0027]    It is apparent from the equilibria described above that through increasing the relative concentration of a component through addition, or by reducing one by depletion, the balance can shift to either precipitate or dissolve silica [29, 34-85]. For example, addition of water to a silica saturated fluorosilicic acid solution renders it supersaturated, leading to solid silica precipitation or its deposition as a film [29, 68-85]. 
         [0028]    Much of the development done on silica based LPD has dealt with deposition on silicon and glass sheets. Silicon substrates have been extensively used with LPD in semiconductor manufacturing as a means of producing conformal insulating films with low dielectric constants. Film densities, impurity incorporation, the effect of annealing conditions and their associated influence on electrical behavior have been extensively studied. Studies involving deposition on glass have generally centered on altering visual properties, such as reflectivity or color. 
         [0029]    Deposition of silica from fluorosilicic acid solutions is always accompanied by some level of fluoride incorporation in the film. A typical range is 1.8-6.25 wt. % [62, 74]. Conditions producing higher film growth rates produce higher fluoride concentrations. This is not just a surface phenomenon; rather the fluorine is resident throughout the film as treatment with boiling water has been demonstrated to have a limited effect on reducing bulk fluoride concentration [65]. 
         [0030]    Removal of fluorine following LPD from fluorosilicic acid solutions is possible at elevated temperatures. Thermal annealing is effective in facilitation of fluoride migration to the surface, where it is lost from the film to the gas phase. With treatment at ≧700° C. the fluorine is completely removed from the surface. While these conditions are acceptable to silica layers deposited on silicon substrates, these temperatures are sufficiently high so as to physically alter or deform the targeted dimensions of borosilicate substrates and should therefore be avoided. Because of this intolerance of high temperatures, a non-zero weight percent fluoride content on the surface of the borosilicate glass remains and can be used as an effective indicator that glass articles have been subjected to a LPD coating process employing fluorosilicic acid solutions. It is our opinion that the introduction of permanent fluoride contamination into LPD treated glass substrates may have previously served as a deterrent toward consideration of this type of coating by others skilled in the art for articles destined for use in the flow path of a chromatographic system. 
         [0031]    The annealing induced outward migration of fluoride is accompanied by a densification of the film and reduction of porosity to levels approaching that of thermally deposited silica [74]. Annealing also reduces film stress values from those produced during the deposition process. Auger electron spectroscopy has been used to determine atomic composition depth profiles of LPD deposited and annealed coatings [44, 47, 71]. The thickness and refractive index of the LPD silica layer can be determined by ellipsometry [47, 57, 61, 71, 81, 83]. 
         [0032]    LPD based silica films from a saturated fluorosilicic acid solution have been demonstrated to yield smoother surfaces having a lower surface area per square unit of space as compared to untreated glass substrates. The technology is employed in the solid state electronics industry to planarize and smooth silicon-based substrates [35, 39]. 
       Vials/Vessels for Analytical Samples 
       [0033]    In the same way it is important to minimize sample/liner interactions that can result in undesirable chemical reactions, decomposition, or permanent adsorption of the sample, it is equally important that the glass vessels used to store the sample prior to introduction to the GC inlet also have the same inert qualities. Common vessels employed in GC analysis to store samples include glass vials (generally for on-site prepared samples) [17] and ampoules (generally for sample standards or long term storage) [17]. Sample vials are commonly available made of borosilicate glass [17], less commonly quartz and much less commonly metal. Sample vials and ampoules are commonly used to contain samples in gas as well as liquid form. In the interest to further protect the chemical integrity of the samples being stored, often the vials are chemically deactivated using similar procedures as described for borosilicate liners [17]. 
         [0034]    Because the sample is at least temporarily contained in the liner until it is introduced into the GC column, the liner device itself can be described as a sample container within the GC sample path. For the purpose of this disclosure the term ‘container’ is used to describe any device employed to store or direct the sample throughout the GC analytical path and includes glass or metal sample vials, ampoules, cylinders, inlet liners, GC columns, or coupling devices employed to direct the sample to the GC detector. 
       Discussion on Doping and Dopants 
       [0035]    Organic and organometallic compounds with useful optical and electronic properties have been used as dopants in porous Vycor glass [92-94]. 
         [0036]    Organic dyes have been infused into Vycor pores [95-97]. Unblocked pores containing dopants have been used in gas sensing applications [98]. The dopants have also been encapsulated by organic polymers within these pores [99-103]. 
         [0037]    The mild conditions required for the creation of sol-gel glasses is compatible with a wide range of dopants that constitute the same family as those described above for infusion into porous Vycor glass. Because of a lack of interconnected pores, the chromophoric species are usually present during the gelation process. Further ripening of the gel can take place without damaging the entrained dyes, salts, or chromophoric particles [104-110]. 
       Discussion on Thermochromic and Photochromic Dyes 
       [0038]    Dyes that produce a color change with temperature are referred to as thermochromic and have been the subject of extensive study [111-117]. A number of chemical classes exhibiting this behavior have been reported, and include perylene dyes, encapsulated leucodyes, and some inorganic compounds. 
         [0039]    In addition, many photochromic compounds (those that change color on exposure to light at specific wavelengths) exhibit thermochromic behavior. Some examples of this class of compounds include spiropyrans, spiroxazines, and ethylene aromatics, and the color change is due to often reversible molecular rearrangements giving rise to differences in conjugation or ionic structure. Thermochromic and photochromic indicators have been introduced into both porous Vycor glass, and sol-gel glasses, with the polarity and geometric constraints in their vicinity affecting the stabilization of one isomeric form over another. Thus environmental effects can result in thermochromic or reverse thermochromic behavior with the same dye molecule. Encapsulation of the dyes within the pores of these inorganic glass matrices has been reported using polymethylmethactylate to yield transparent composites with the anticipation that they could lead to the development of three-dimensional high density memory arrays [108]. 
         [0040]    The thermochromic effect can be gradual, with the color intensity varying with the percentage of (lye molecules in each state. Photochromic images previously set through light exposure can sometimes be erased through thermochromic relaxation. 
       SUMMARY OF THE INVENTION 
       [0041]    We present here a borosilicate-based liner or container before deactivation having a smooth, high purity silica uppermost surface, where the uppermost surface is deposited using a liquid phase deposition process, where high purity silica is defined as having less than a total of 10% of a combination of boron oxides, and metal or other element oxides besides silicon on a mass basis. We thus disclose a superior process to standard leaching technologies as the leaching process leaves behind a comparatively high surface area, high surface energy substrate, which can compromise the completeness and uniformity of the final liner or container&#39;s deactivation coating. 
         [0042]    We also describe a method of annealing that is adequate to remove contaminating fluoride concentrations to acceptable levels so as not to interfere with subsequent deactivation processes. We also define the uppermost surface of the liner or container as the region extending inward from zero to 100 nanometers from the surface of the article. For the purpose of this disclosure the uppermost layer may result from multiple repeat LPD cycles on the same substrate. The term ‘layer’ and ‘uppermost layer’ may refer to at least one layer deposited on the substrate surface, with more than one layer being present next to or on top of one another. 
         [0043]    We further present the application of LPD based silica films, with a subsequent deactivation process, with glass containers used for handling or storing chemical samples. 
         [0044]    Previously, liners employing color indicators have been demonstrated using porous glass substrates [14]. Similar practice has been demonstrated here where the indicator is incorporated into the LPD layer, which can be deposited on both porous and non-porous containers [86-91]. 
         [0045]    We further present a borosilicate liner or container having a smooth, high purity silica uppermost surface, where the uppermost surface incorporates an indicator. 
         [0046]    We further present a borosilicate liner or container having a smooth, high purity silica uppermost surface, where the uppermost surface incorporates multiple overlaying layers where at least one of the layers incorporates an indicator. 
         [0047]    We further present a liner or container having a deposited high purity silica layer, which employs indicators within the silica layer as a means to easily identify one liner or container from another. For the purpose of this disclosure the term indicator relates to any element, compound, dopant, or mixture additive to the glass substrate that modifies the native color or transparency of the glass substrate. 
         [0048]    We further present here a liner or container having a deposited high purity silica layer which employs indicators as a means of visually identifying the thermal state of the liner. 
         [0049]    We further present here a liner or container having a deposited high purity silica layer which employs indicators as a means of determining “use status”, wherein it is possible to visually identify if the liner or container has been previously subjected to high temperature and optionally the duration of exposure beyond a specific threshold. 
         [0050]    We further present here a liner or container having a deposited high purity silica layer which employs indicators with controlled physical placement as a means of identifying the orientation of the liner. 
         [0051]    We further present here a liner or container having a deposited high purity silica layer which employs colored indicators that are visible under ordinary and/or ultraviolet light as a means of decoration, identification, or counterfeit detection. 
         [0052]    In addition, we present a liner or container having a deposited high purity silica layer wherein the indicators are effectively blocked from surface interactions through thermally stable chemical capping. 
         [0053]    We further present a liner or container having a deposited high purity silica layer which employs indicators receptive to photolithographic imaging. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0054]      FIG. 1  are representations of several types of sample vials employed for storing and distributing analytical samples and sample standards. 
           [0055]      FIGS. 2A through 2I  are representations of several types of gas chromatography injection port liners known in the art. 
           [0056]      FIG. 3   a  represents the general manufacturing process (Scheme 1) for quartz liners,  FIG. 3   b  represents the general manufacturing process (Scheme 2) for borosilicate liners or containers employing the acid leach process, and  FIG. 3   c  represents the inventive manufacturing process (Scheme 3) for borosilicate liners or containers of the invention employing the LPD process. 
           [0057]      FIGS. 4 through 10  are representations of various aspects of the preferred embodiment of a liner utilizing our invention that interfaces into a gas chromatograph injection port. A similar composition or structure may also be inferred for other types of containers. The enlarged portions of the figures represent close-up views of the inner and outer walls of the liners or containers, showing the various layers and coatings deposited thereon. 
           [0058]      FIG. 11  is a graphical representation of a chromatogram generated of a chemical mixture injected directly onto a column, bypassing contact with an injection port liner using a deactivated injection port liner constructed according to the prior art and illustrated in  FIG. 1 . 
           [0059]      FIGS. 12 through 17  are graphical representations of chromatograms generated of various chemical mixtures using both commercially available injection port liners ( FIGS. 12 ,  13 ,  15 , and  16 ) and prototypes ( FIGS. 14 and 17 ) constructed according to the preferred embodiments of this invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0060]    In one preferred embodiment of this invention as illustrated in  FIG. 3   c , a container such as a borosilicate liner or vial is leached with diluted hydrochloric acid to remove the accessible boric and alkali metal oxides, and then washed to neutrality with deionized water. The article is then immersed in a silica saturated (or supersaturated) solution of fluorosilicic acid, optionally containing additives or indicators so as to impart the desired properties in the finished product. The temperature may optionally be raised to accelerate the silica deposition rate. At the conclusion of treatment, the article is removed from the solution and rinsed thoroughly with deionized water. It is then placed in a vessel and while purged with an inert gas, it is heated to as high as 550° C. from several minutes to several hours before cooling. 
         [0061]    The resulting liner or container is thus coated with a film exhibiting the properties shown in Table 1, and is finally deactivated with silanes using procedures described in the art. 
         [0000]    
       
         
               
             
               
               
               
               
             
               
               
               
               
             
           
               
                 TABLE 1 
               
             
             
               
                   
               
               
                 Properties of glass compositions 
               
             
          
           
               
                   
                   
                 Unleached 
                   
               
               
                   
                 Unleached 
                 Fused Silica/ 
                 LPD coating (uppermost 
               
               
                   
                 Borosilicates 
                 Quartz 
                 surface layer) 
               
               
                   
                   
               
             
          
           
               
                 Impurities 
                 ca. 15-30% 
                 &lt;1.0% 
                 &lt;10% 
               
               
                 (boron oxide 
               
               
                 and metal oxides 
               
               
                 basis), wt. 
               
               
                 Fluorine, % wt. 
                 ~0.00 
                 ~0.00 
                 Between 0.05 and 10% 
               
               
                 SiO2, wt. 
                 ca. 70-85% 
                 balance 
                 balance 
               
               
                 Softening 
                 ca. 650-820 
                 ca. 1650 
                 does not significantly 
               
               
                 point, ° C. 
                   
                   
                 contribute to softening 
               
               
                   
                   
                   
                 point of the substrate 
               
               
                 Annealing 
                 ca. 560 
                 ca. 1210 
                 does not significantly 
               
               
                 point, ° C. 
                   
                   
                 contribute to annealing 
               
               
                   
                   
                   
                 point of the substrate 
               
               
                   
               
             
          
         
       
     
         [0062]    In  FIGS. 2A-2I , sectional views of various sample inlet liner configurations known in the art are illustrated.  FIG. 2A  is an example of a straight through sample inlet liner  10 .  FIG. 2B  illustrates a liner  20 , comprising the liner  10  incorporating a matrix  21 , which may be comprised of wool, particles, wire bundles, or other materials know in the art,  FIG. 2C  illustrates a single taper liner configuration  30 ,  FIG. 2D  illustrates a liner  40  having the same configuration as in liner  30 , with the addition of a matrix  41 , similar in composition to that designated as  21  in  FIG. 2B .  FIG. 2E  illustrates a sample inlet liner  50  with dimples or constrictions extending into the inner bore.  FIG. 2F  illustrates a liner configuration  60  with two sets of internal dimples or constrictions; and  FIG. 2G  represents the same type of liner, with the same two sets of dimples or constrictions  70 , but with the addition of a matrix  71  described above that is supported within the zone created by said dimples or constrictions.  FIG. 2H  illustrates a liner  80  having a straight through sample inlet liner with yet three sets of internal dimples or constrictions; and  FIG. 2I  illustrates a sample inlet liner  90  with multiple sets of interior baffles. 
         [0063]    In  FIG. 4 ,  401  is an example of the present invention and is fabricated from borosilicate glass. In the enlarged view of a portion of this figure,  405  represents the inner region of the liner tube, with  406  being the outer. Region  404  represents the borosilicate glass body from which the liner is fabricated, with  403  illustrating a thin film of silicon dioxide deposited on the inner and outer walls using the process of this invention. In order to eliminate absorptive activity towards analytes, the liner is coated with a final layer of a deactivant that is usually silane or siloxane in nature, but may be comprised of other moieties as known in the art, and designated as  402 . 
         [0064]      FIG. 5  is a rendering of a borosilicate or quartz liner with the main body shown as  501 , and the wall view expanded as  505  and the inner and outer regions designated  508  and  509 , respectively. Section  504  represents a film of silicon dioxide deposited on the glass surface using the LPD process and containing one or more types of dye molecules  506  co-deposited at the same time, and fully encapsulated within the film. The liner is coated inside and out with a deactivant as in  FIG. 2  and designated in this Figure as  502 . 
         [0065]      FIG. 6  illustrates a borosilicate or quartz liner  601  as in the preceding Figure, and expanded as  605 , but with the addition of a second silica deposition layer  603  containing one or more dye molecule families ( 604 ) that may be the same or different from those ( 606 ) deposited in the first silica layer  607 . Again, the inner and outer wall regions are designated in this figure as  608  and  609 , respectively. The liner is coated inside and out with a deactivant as in the preceding. Figure and designated in this Figure as  602 . 
         [0066]    The liner represented in  FIG. 7  as  701  and the core glass or quartz wall designated as  703 , contains a selected region that is coated with a silica film  705  and containing one or more dye molecule families  706  co-deposited and fully encapsulated within the film. Selected deposition may be accomplished by partial immersion into a silica saturated fluorosilicic acid solution containing the desired dye(s) or by masking off of regions where solution contact is to be prevented. Again, a suitable deactivant film  702  is shown applied on the inner  704  and outer  707  walls of the liner to minimize analyte interaction with residual active sites. 
         [0067]    The liner illustrated in  FIG. 8  and represented by  801  and body  804  contains a layer of liquid phase deposited silica  807  in a selected region only and optionally containing one or more types of dye molecules  806 . This layer is shown on both inside  805  and outside  808  surfaces of the tube, but may be selectively placed on only one, or with myriad gaps as desired according to the masking/immersion method used. The LPD layer first placed on the tube and the remaining surfaces are coated with a second silica film using the methods of this invention  803  that totally encapsulates the liner. In this Figure, the second coating of silica is clear and is intended to illustrate a barrier layer capable of barring passage or diffusion of any buried atoms. A deactivant layer  802  is shown as a final coating to mask silanol sites or other residual reactive regions. 
         [0068]    The liner illustrated in  FIG. 9  and represented by  901  and body  905  contains a layer of liquid phase deposited silica  907  in a selected region only and optionally containing one or more types of dye molecules  908 . This layer is shown on both inside  906  and outside  909  surfaces of the tube, but may be selectively placed on only one, or with myriad gaps as desired according to the masking/immersion method used. The LPD layer first placed on the tube and the remaining surfaces are coated with a second silica film using the methods of this invention  903  that totally encapsulates the liner. In this Figure, the second coating of silica also contains one or more families of dye molecules  904  intended to both shield the underlying surface from exposure to the environment and impart a secondary visual effect. A deactivant layer  902  is shown as a final coating to mask silanol sites or other residual reactive regions. The tube in  FIG. 10  as illustrated as  1001  is a representation of another aspect of the embodiment of this invention, with an expanded view as  1004 . The region  1008  shows the presence of “through pores”, or pores providing fluidic communication between the inner  1009  and outer  1007  walls of the liner, such as would be found with porous Vycor glass as the substrate material. These pores are not initially present in the tube, but result from an acid leaching process wherein interconnected regions of borate-rich glass that permeate through the glass are selectively solubilized and removed. The section identified as  1002  is a superficial pore that extends inward from either the interior  1009  or exterior  1007  surface of the tube. This type of pore exists in Vycor type glasses, but they also are prevalent on the surface of acid leached borosilicate glasses (including Pyrex and other brands) that have not undergone phase separation into continuous regions. These pores are generally small and don&#39;t penetrate more than a few tenths of microns from the surface, but their physical presence is easily noted as an increased surface roughness after acid leaching compared to that of the initial glass. All pores contribute to an increased surface area over that of the solid body [18-23]. The present illustration shows the presence of a film of LPD silica that fills both superficial and through-hole pores and covers the exposed surfaces of the tube. It optionally can contain one or more families of dye molecules  1003  that are encapsulated within the clear film  1005  to impart the desired optical properties to the object. This film also accomplishes a hole-plugging task that effectively eliminates fluidic communication between the inner and outer surfaces of the tube. The liner may be deactivated with a suitable film shown as  1006  to provide inertness toward analytes. 
         [0069]      FIG. 11  depicts a section of a chromatogram of a pesticide mixture that was obtained from Ultra Scientific. The key areas illustrated show the elution region of endrin and its typical breakdown products endrin aldehyde and endrin ketone. It also shows the presence of DDT, another chlorinated pesticide. The chromatogram was acquired using cold on-column injection of 1 μL to eliminate injection port liner contributions to analyte breakdown, and used a 15 meter, 0.53 mm ID, 1 um film, Rxi-5MS column for the separation. The run conditions were: Inlet: 50° C. (hold 0.5 min) to 280° C. @ 20° C./min (hold 3 min), Constant flow @ 5 mL/min (He); Oven: 45° C. (hold 0.5 min) to 275° C. @ 20° C./min (hold 3 min); Detector: uECD, 310° C., N 2  make-up gas flow of 60 mL/min. 
         [0070]    The peaks are identified on the chromatogram with their absolute area counts in parentheses, and the bulk endrin and DDT concentrations in the test mixture were 50 and 100 pg/μL respectively. The identification of the eluted peaks and their absolute area counts was based on previous studies with internal standards. In this experiment, the endrin breakdown was found to be 0.62%, which may be considered a baseline value for this particular standard using the separation column and conditions indicated. 
         [0071]      FIG. 12  illustrates a chromatogram of a commercial single gooseneck style liner containing borosilicate wool, and manufactured according to typical procedures reported in the art, with the analytical conditions listed below and using the mixture in  FIG. 11 : 
         [0000]    Inlet temperature: 250° C., Splitless injection, at 20 mL/min @ 0.5 min, constant flow @ 1.5 mL/min, helium carrier 
       Oven: 150° C. to 240° C. @ 20 C/min to 265° C. @ 6° C./min 
       [0072]    Column: 20 meter, 0.18 mm ID, 0.18 μm film, Rxi-5sil-MS
 
Detector: μECD, 300° C., N 2  make-up gas flow of 60 mL/min
 
         [0073]    The same analytical standard was used for the analysis, and 1 μL was injected. The endrin breakdown level was found to be 15.8% and that of DDT to be 4.3%. The difference in breakdown levels from those found in  FIG. 11  may be attributed to analyte breakdown in the heated injection port liner. 
         [0074]      FIG. 13  shows a chromatogram using the best competitive liner available as determined by exhaustive benchmark testing. It was tested using the mixture from  FIG. 11  with the following conditions: 
         [0000]    Inlet temperature: 220° C., Splitless injection, 15 sec. hold time, 20 mL/min purge flow, column flow @ 1.5 mL/min, helium carrier
 
Oven: 120° C. (hold 1 min.) to 225° C. @ 20° C./min to 280° C. @ 6° C./min. (hold 7 min)
 
Column: 20 meter, 0.18 mm ID, 0.18 um film, Rxi-5-MS
 
Detector: μECD, 290° C., N 2  make-up gas flow of 60 mL/min
 
         [0075]    The endrin breakdown level was found to be 2.8% and that of DDT to be 1.2%. The difference in breakdown levels from those found in  FIG. 11  may be attributed to analyte breakdown in the heated injection port liner. 
         [0076]      FIG. 14  illustrates a chromatogram obtained in the analysis on the pesticide mixture in  FIG. 11  with an injection port liner fabricated with a liquid phase deposition layer of silica containing Rhodamine B dye below the deactivation layer, and prepared according to this invention. The analytical conditions for this run were the same as  FIG. 12 . 
         [0077]    The endrin breakdown level was found to be 1.9% and that of DDT to be 1.0%. The difference in breakdown levels from those found in  FIG. 11  may be attributed to analyte breakdown in the heated injection port liner. It should be noted that this improved inertness toward analyte breakdown was achieved with the prototype liner of the invention compared to the prior art liner used in connection with  FIG. 13 , even though the temperature of the injection port was 30° C. higher here than in the prior case ( FIG. 13 ). Increasing the injection port temperature is known to increase the amount of endrin and DDT breakdown in an analysis. 
         [0078]    The chromatogram depicted in  FIG. 15  was generated to quantitate a typical level of loss of 2,4-dinitrophenol, which is an acidic analyte shown to be sensitive toward active sites in GC injection port liners. Its response is reported relative to the internal standard acenaphthene using cold on-column injection analysis, and the value indicating no absorptive losses is 0.31. This single gooseneck liner containing wool gave a response factor of 0.049, when run under the following conditions: 
         [0000]    Inlet: 250° C., Constant pressure at 50 psi, Splitless injection, split flow @ 20 mL/min @ 1 min 
       Oven: 50° C. to 150° C. @ 20° C./min 
       [0079]    Column: 15 m, 0.25 mm ID, 0.25 um film, Rxi-5MS
 
Detector: FID, 300° C., H 2  @ 40 mL/min, Air @ 450 mL/min, N 2  @ 45 mL/min
 
The sample was 1 μl, of a 10 ng/μL solution of 2,4-dinitrophenol and 10 ng/μL of acenaphthene
 
         [0080]      FIG. 16  shows a chromatogram using the best competitive liner available as determined by exhaustive benchmark testing for the analysis of 2,4-dinitrophenol. The conditions and the sample were the same as in  FIG. 15 , and the response factor for 2,4-dinitrophenol was 0.298 relative to acenaphthene. 
         [0081]      FIG. 17  illustrates a chromatogram obtained in the analysis of 2,4-dinitrophenol with an injection port liner of the invention fabricated with a liquid phase deposition layer of silica containing Rhodamine B dye below the deactivation layer, and prepared according to this invention. The conditions and the sample were the same as in  FIG. 15 , and the response factor for 2,4-dinitrophenol was, 0.301 relative to acenaphthene, showing at least comparable results to those in  FIG. 16 , and a considerable improvement over the results with the liner tested in  FIG. 15 . 
       EXPERIMENTAL RESULTS 
       [0082]    The following examples are presented to show various aspects of the process of the invention. 
       Example 1 
       [0083]    In this example, simple coloration of a single gooseneck borosilicate glass liner, illustrated in  FIG. 2C  is described. Silica powder was added in intervals to a 3.2M solution of fluorosilicic acid and stirred magnetically until no more dissolved. The suspension was then placed in a freezer at −9° C. overnight. A portion of the suspension was taken and diluted 1:1 with a 0.2% solution of Rhodamine Bin water. After brief mixing, the suspended silica was removed by filtration through a 0.45 μm PTFE filter. A 4 mm ID single gooseneck borosilicate glass liner suitable for use in an Agilent 6890 Gas Chromatograph was rinsed with acetone, dried, and then immersed in the freshly filtered solution. The vessel was capped, and periodically mixed. After 4 hours, the liner was removed from the solution and rinsed well with water. It exhibited a transparent dark pink/purple color that was uniform throughout. 
       Example 2 
       [0084]    A non-cationic dye was utilized as a colored indicator, even though it has limited water solubility in its acid form, but still exhibiting an intense fluorescence. A silica saturated fluorosilicic acid (SSFA) solution prepared as in Example 1 above was filtered and diluted with an equal volume of an aqueous solution saturated with fluorescein. A liner as in Example 1 was immersed in the solution and agitated periodically over 16 hours. The liner was removed from the solution, rinsed well with water and dried. It appeared almost colorless, but exhibited some visible fluorescence when illuminated with ultraviolet light. 
       Example 3 
       [0085]    A SSFA solution prepared as in Example 1 above was filtered and diluted and mixed with an equal volume of a 0.2% solution of Crystal Violet dye in water. Crystal Violet is a member of the family of triphenylmethane cationic dyes, whose color is a function of the local pH. A liner was treated with this solution as in Example 2. It exhibited a transparent light blue color. The liner was rinsed well with water until neutral pH was achieved and no dye was extractable from the glass surface. The liner was then dried in a forced air oven. After overnight treatment at 200° C., the color was as before, with no visible change having occurred. 
       Example 4 
       [0086]    A liner was treated as in Example 3 above, but with Malachite Green oxalate (another cationic dye from the triphenylmethane family) as the dye. It exhibited a transparent dark green color. The liner was rinsed well with water until neutral pH was achieved and no dye was extractable from the glass surface. The liner was then dried in a forced air oven. After overnight treatment at 200° C., the color was as before, with no visible change having occurred. 
       Example 5 
       [0087]    Examination of less thermally stable dyes as thermochromic indicators was demonstrated in this example. A borosilicate glass liner was treated as in Example 3 above, but with the phenothiazine compound Methylene Blue hydrate as the dye. It exhibited a transparent dark blue color. The liner was rinsed well with water until neutral pH was achieved and no blue dye was extractable from the glass surface. The liner was then dried in a forced air oven. After overnight treatment at 200° C., the color was gone, leaving the liner clear and colorless. 
       Example 6 
       [0088]    A liner was treated as in Example 3 above, but with anionic Methyl Orange as the dye. It showed no visible evidence of dye incorporation. This result is consistent with reports in the literature that cationic dyes are more likely to be incorporated in the growing silica film than anionic ones. 
       Example 7 
       [0089]    A liner was treated as in Example 3 above, but with another anionic compound, Trypan Blue as the dye. It showed, no visible evidence of dye incorporation. This result is consistent with reports in the literature that cationic dyes are more likely to be incorporated in the growing silica film than anionic ones. 
       Example 8 
       [0090]    Dyes with higher thermal stability and thermochromic behavior as indicators were utilized in the following example. A borosilicate glass liner was treated as in Example 3 above, but with Neutral Red as the dye. It exhibited a transparent brick red color. The liner was rinsed well with water until neutral pH was achieved and no dye was extractable from the glass surface. The liner was then dried in a forced air oven. After overnight treatment at 200° C. in air, the color was as before, with no visible change having occurred. The temperature was increased to 400° C. and the liner was examined after 1 hour exposure. It had turned a transparent light brown color. Heating was continued at 400° C. in air and the liner periodically examined for color change. None occurred and the experiment was terminated after 72 hours accumulated heating time at 400° C. 
       Example 9 
       [0091]    The effect of the LPD process with wool present inside the liner, along with annealing and deactivation were demonstrated in the following example. A single gooseneck borosilicate glass liner was loaded with 6 mg of 4 μm (nominal fiber diameter) fused quartz wool and leached with 3M HCl solution for 30 minutes. The acid was removed by rinsing with water until the pH was neutral. The liner was then oven dried at 120° C. for 30 minutes. The initially smooth glass surface was noticeably rougher after the acid leaching process as determined by physical feel. 
         [0092]    Silica saturated fluorosilicic acid solution prepared in Example 1 was allowed to warm to room temperature and was held for 24 hours. The excess silica was removed by filtration and 20 mL of this solution was placed in a plastic tube. The solution was diluted with 20 mL of water that had 2 drops of a 0.2% Rhodamine B solution added to it. After mixing well, the acid leached liner was immersed in the solution and allowed to stand 6 hours with occasional swirling. The liner was then removed from the solution and rinsed with water until the pH was neutral. A faint pink transparent coloration of the glass was observed, with more intensity of color on the wool surface. The rough surface had also developed a very smooth feel as a result of the deposition treatment. The liner was placed in a stainless steel vessel, purged with helium, and heated to 250° C. for 5 hours to anneal the freshly deposited silica and reduce the overall fluoride content. The liner was then deactivated using standard reagents and processes and evaluated for inertness by gas chromatography. Results are shown in  FIGS. 14 and 17 . 
       Example 10 
       [0093]    A SSFA solution prepared as in Example 1 above was filtered, diluted and mixed with an equal volume of water. Two drops of Rhodamine B solution (0.2% in water) was added, and a single gooseneck liner was immersed in the solution and the plastic vessel containing it was closed. The vessel was placed in an oven at 35° C. and within 2 hours pink particles had formed and coated both the inside of the vessel and the liner. The liner itself showed a pink coloration similar to the liner from Example 9 after water rinsing and drying, but with a significant haze. The surface of the liner was also much rougher in feel than the liner from Example 9. This example demonstrated the effect of combined dilution and heating in one step. Homogeneous nucleation occurred from the supersaturation level being too high, such that particle formation competed with film growth. 
       Example 11 
       [0094]    In this example, the LPD solution was not diluted with an equal volume of water, but was heated in order to effect silica supersaturation. A SSFA solution prepared as in Example 1 above was filtered and mixed with two drops of Rhodamine B solution (0.2% in water). A single gooseneck liner was immersed in the solution in a closed plastic vessel. The vessel was placed in an oven at 35° C. and allowed to heat overnight. The vessel was cooled and the liner rinsed well with water until pH neutral. The liner was transparent with a transparent light pink color and exhibited no sign of haziness, indicating that only film formation occurred without homogeneous nucleation. The liner surface was shiny and smooth. 
       Example 12 
       [0095]    Physical blocking of the glass surface by a hydrophobic mask was used in this example to demonstrate the need for LPD solution contact with the glass surface for film formation to occur. A single gooseneck liner was immersed to a depth of 1 inch into melted paraffin wax and then removed. After the wax had hardened, the liner was immersed into an SSFA solution as in Example 3, but containing Rhodamine B as the dye. After the deposition treatment, the liner was rinsed with water, and then hot toluene. The pink clear coating was only present where the contact with the wax had not occurred, the latter having served as an effective mask against silica deposition. 
       Example 13 
       [0096]    Multiple thermochromic indicators in multiple deposition steps were used in this example. The partially coated liner from Example 12 was immersed in an SSFA solution containing methylene blue as in Example 3, but with about 10% of the dye concentration. The liner was then rinsed well with water and dried. The liner exhibited a blue color in the region where the wax mask had originally been, and a purple color where the Rhodamine B had already been deposited. It was then placed into an oven exposed to air and heated in increments of 50° C., holding for 30 minutes at each temperature. The first noticeable changes occurred at 200° C. The light blue liner had lost the Methylene Blue dye component, leaving behind a pink Rhodamine B color in the originally dyed region. The pink color remained until the temperature testing reached the 400° C. hold step, when it became clear and colorless. The stepwise color loss demonstrated an irreversible maximum temperature indicating thermochromic effect. 
       Example 14 
       [0097]    In another example of multiple thermochromic indicators, but co-deposited within the same film, a borosilicate glass single gooseneck liner was immersed in an SSFA solution containing a mixture of methylene blue and neutral red dyes as in Example 3. The liner was then rinsed well with water and dried. It was dark purple in color and smooth. It was placed in an oven and heated gradually to 400° C. using the process described in Example 13. At 200° C., the dark blue liner turned much darker, appearing almost black. The dark liner remained black until the hold at 350° C. where it turned dark brown. This corresponded to the decomposition of the heavily doped methylene blue dye leaving only the neutral red dye. On continued heating to 400° C., the liner turned a light brown color similar to that seen with the liner in Example 8. The stepwise color change in this Example thus demonstrated an irreversible maximum temperature indicating thermochromic effect. 
       Example 15 
       [0098]    The effect of deposition of silica using the process of this invention on surfaces other than silica was shown in this example. A single gooseneck liner was labeled with a silkscreened ceramic glaze decal and heated in a muffle furnace at 550° C. for several hours to fuse the pigment into the glass surface. After cooling, the liner was immersed into an SSFA solution as in Example 3 above, but with Rhodamine B as the dye. It exhibited a pink color. After rinsing and drying, the liner was examined for signs of etching or attack on the inorganic pigment. None was apparent, and the image resolution was not affected. The liner was now smooth over its entire surface, where the image had imparted a rough feel before. Microscopic examination revealed the presence of a smooth, conformal pink film over the entire article. 
       Example 16 
       [0099]    A single gooseneck borosilicate glass liner was loaded with 4 μm fused quartz wool and treated the same as the liner in Example 9, but with the omission of the Rhodamine B indicator. The treatment provided a very smooth and colorless liner. When tested chromatographically for inertness, this liner gave essentially identical results compared to the performance of the light pink colored liner produced in Example 9. 
       Example 17 
       [0100]    In this example, the interior of a sample vial is deactivated using one preferred embodiment of this invention. A 40 mL borosilicate glass screw cap vial was filled with 3 N hydrochloric acid and allowed to stand for 30 minutes. The solution was removed and the vial was rinsed with deionized water until neutral pH was obtained. Silica saturated fluorosilicic acid solution prepared in Example 1 was allowed to warm to room temperature and was held for 24 hours. The excess silica was removed by filtration and 20 mL of this solution was placed in the acid leached vial. The solution was diluted with 20 mL of water that had 2 drops of a 0.2% Rhodamine B solution added to it. The vial was capped, mixed well, and allowed to stand 6 hours with occasional swirling. The solution was then removed and the vial rinsed with water until the pH was neutral. A faint pink transparent coloration of the glass was observed. 
         [0101]    The vial was placed in a stainless steel vessel, purged with helium, and heated to 250° C. for 5 hours to anneal the freshly deposited silica and reduce the overall fluoride content. The vial was then deactivated using standard reagents and processes. The light pink coating on the vial interior was very smooth and repellant to liquid water. Acetone was added to the midpoint of the vial, which was then capped. The solution showed no hint of dye leaching after 3 weeks exposure to the solvent. 
         [0102]    The references referred to in this application and listed below are hereby incorporated herein by reference. 
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