Dispersive solid-phase extraction of alkaloids and polyphenols using borate hypercrosslinked polymers.

In this study, a borate hyper-crosslinked polymer was synthesized by crosslinking 1-naphthalene boric acid and dimethoxymethane via the Friedel-Crafts reaction. The prepared polymer exhibits excellent adsorption performance toward alkaloids and polyphenols with maximum adsorption capacities ranging from 25.07 to 39.60 mg/g. Adsorption kinetics and isotherms model results indicated the adsorption was a monolayer and chemical process. Under the optimal extraction conditions, a sensitive method was established for the simultaneous quantification of alkaloids and polyphenols in green tea and Coptis chinensis by coupling with the proposed sorbent and ultra-high performance liquid chromatography detection. The proposed method exhibited a wide linear range of 5.0-5000.0 ng/ml with R2 ≥ 0.99, a low limit of detection (0.66-11.25 ng/ml), and satisfactory recoveries (81.2%-117.4%). This work provides a simple and convenient candidate for the sensitive determination of alkaloids and polyphenols in green tea and complex herbal products.

Development of a rapid HPLC method for quantification of the copper tetramibi tetraflourborate in a kit for preparation of Technetium 99 m Sestamibi Injection.

Radiopharmaceuticals are radioactive compounds that can be used for diagnostic and therapeutic purposes. Technetium (99mTc) Sestamibi is the most commercialized radiopharmaceutical in the world. It includes a coordination complex consisting of the radioisotope 99 m technetium bound to six copper tetramibi tetrafluorborate ligands, and is mainly used to image the myocardium via scintigraphy. As radiopharmaceuticals are regarded as drugs, they are subject to the same regulations; therefore, the objective of this study was to develop a quantification method for the active pharmaceutical ingredient before their complexation with the radioisotope by employing high-performance liquid chromatography (HPLC) methodology. A simple and efficient method (retention time = 2.5 min) was developed and validated for copper tetramibi tetrafluorborate in the final product using a buffer and organic solvent mixtures (ACN-methanol-ammonium sulfate buffer) and a C18 column. The analytical protocol was fast, taking around 30 min until evaluation of results. The validation parameters were evaluated with satisfactory results: in terms of linearity r > 0.99 (160-240 µg/mL) and no deviation was observed. The RSD of precision was <5%, and an average recovery of 99% was observed for accuracy. The proposed method was thus considered adequate for routine analysis in the pharmaceutical industries.

Dual optical detection approach for capillary electrophoresis following two-step liquid-liquid extraction to determine ten phenols in water samples.

In this research, the analytical method was developed and evaluated for determining phenol and its nine derivatives belong to the US EPA priority pollutant list in water samples by using dual-channeled capillary electrophoresis (CE) coupled with two types of optical detectors, namely LED-induced fluorescence (LEDIF) and ultraviolet (UV) detectors. The optimal background electrolytes for the first and second CE channels were 20 mM borate (pH 9.80) with 400 µM fluorescein and 55 mM borate (pH 11.75), respectively. The two-step liquid-liquid extraction (LLE) was used for sample preparation and enrichment, in which phenol and its derivatives were extracted from the aqueous phase using 10 mL of n-hexane/1-octanol (60/40, v/v) and then were back extracted into a 0.1 M NaOH as a final acceptor phase. Under the optimal CE and two-step LLE conditions, the enrichment factors of 10 phenols were 184 - 1120-fold, and the method detection limits were lowered to 0.02-0.60 µg/L. The obtained intra-day and inter-day precisions in terms of relative standard deviations (RSD) were between 4.0 and 7.3 % and 6.7 and 14 %, respectively. This approach was used to determine phenols in water samples, with recoveries ranging from 82.0 to 108.9 %. In combination with sample enrichment by two-step LLE extraction, this is the first CE study conducted to determine phenols in the EPA list using two detector approaches, specifically CE-LEDIF/CE-UV.

A highly selective fluorescent probe for BO3(-) based on acetate derivatives of coumarin in aqueous solution and thimerosal.

The acetate derivatives of coumarin exhibited a prominent turn-on type signaling behavior toward BO(3)(-) ions over other common anions. Signaling is based on the selective deprotection of acetate groups by perborate, which resulted in significant fluorogenic signaling in an acetate buffered solution (pH 5.0). Interestingly, the detection process makes the raw material of 7-hydroxycoumarin regenerate, and the probe could be applied for the detection of BO(3)(-) of thimerosal. Furthermore, the optical properties of the probe and its BO(3)(-)-induced product were theoretically studied based on density functional theory (DFT) and the time-dependent DFT (TDDFT) explored at the B3LYP/6-311+G (d, p) level.

Simple, fast and reliable CE method for simultaneous determination of ciprofloxacin and ofloxacin in human urine.

A simple, fast, and accurate capillary zone electrophoresis method has been developed for the determination of ciprofloxacin and ofloxacin. This method uses liquid-liquid extraction. Therefore, it is characterized by a very simple procedure of sample preparation but at the same time satisfactory precision and accuracy. The extraction process of the same urine sample was repeated three times. The extraction protocol was performed each time for 15 min with 1 mL of dichloromethane and chloroform mixture in a 3:1 volume ratio. A 0.1 mol/L phosphate-borate buffer (pH 8.40) was selected as the background electrolyte. UV detection was performed at 288 nm. The separation was carried out at a voltage of 16 kV, at a temperature of 25 °C. Experimentally evaluated LOQ values for ciprofloxacin and ofloxacin were 0.2 nmol/mL urine and 0.05 nmol/mL urine, respectively. For both analytes the calibration curves exhibited linearity over the entire tested concentration range of 1-6 nmol/mL urine. The precision of the method did not exceed 15%, and the recovery was in the range of 85-115%. The developed and validated procedure was applied to analyze human urine for the content of ciprofloxacin and ofloxacin.

Detection of Sodium Formaldehyde Sulfoxylate, Aluminum, and Borate Compounds in Bread and Pasta Products Consumed by Residents in Jilin Province, China.

ABSTRACT: Food additives are widespread in the human diet; however, their excessive intake can have an impact on the quality of health. This study evaluated food additives in bread and pasta products consumed by residents in various regions of Jilin Province, People's Republic of China, from 2019 to 2021. We collected samples of bread and six types of pasta products from farmers' markets and morning markets and used high-performance liquid chromatography, UV-visible spectrophotometry, and graphite furnace atomic absorption spectrometry to detect the content of the following food additives: sodium formaldehyde sulfoxylate, aluminum, and borate compounds. For 836 samples in total, we detected the presence of sodium formaldehyde sulfoxylate, aluminum, and borate compounds in excess rates reaching 3.5, 10, and 4.7%, respectively. Aluminum in fried breadsticks exceeded the standard by 40%. The results of this study can be used to assess the overall pass rate of bread and pasta products sold in Jilin Province and support the detection of possible food safety problems.

Assessment of bioaccumulation of glyphosate and aminomethylphosphonic acid in marine mussels using capillary electrophoresis with light-emitting diode-induced fluorescence detection.

Glyphosate or N-(phosphonomethyl)glycine, widely used as herbicide in agriculture to control weeds and to facilitate harvesting, has been included in Group 2A pollutants (probably carcinogenic to humans) by the International Agency for Research on Cancer (IARC). In intensive agricultural areas, runoff and soil leaching are likely to drive glyphosate to surface waters, where the compound is often detected together with its main microbial metabolite, aminomethylphosphonic acid (AMPA). In the present study a method based on capillary electrophoresis coupled with light-emitting diode-induced fluorescence detection has been developed and validated for the determination of the two compounds in whole soft mass of marine mussels (Mytilus galloprovincialis). The method is based on the acidic hydrolysis of lyophilized tissue using 6 M HCl (oven at 110 °C for 22 h) to release the target analytes; their subsequent derivatization using 4-fluoro-7-nitro-2,1,3-benzoxadiazole, was found to be suitable for the sensitive fluorescence detection. To achieve optimum separation of the analytes from the matrix and degradation reagent interferences, the background electrolyte constituted by borate buffer (pH 9.2, 30 mM) was supplemented with 10 mM heptakis(2,6-di-O-methyl)-ß-cyclodextrin. The method was validated for linearity, precision, accuracy, robustness and sensitivity showing LOQ of 0.2 and 1.0 µg/g in fresh tissues, for AMPA and glyphosate, respectively; the recovery values ranged within 88.5 - 94.6% for glyphosate and 70.4 - 76.6% for AMPA. Experimental samples of Mediterranean mussels M. galloprovincialis treated with 100 µg/L or 500 µg/L of both glyphosate and AMPA, showed a dose dependent bioaccumulation of the compounds reaching maximum level of 77.0 µg/g and 11.3 µg/g of AMPA and glyphosate, respectively. The study demonstrates for the first time M. galloprovincialis as potential sentinel organisms for the environmental occurrence of these small amphoteric pollutants.

Effect of citric acid erosion on enamel and dentin and possible protection by a novel bioactive borate adhesive system.

OBJECTIVES: This study examined the ability of a borate adhesive to protect enamel/dentin surfaces from acidic erosion and its effect on the shear bond strength (SBS) of enamel/dentin to resin composite. MATERIALS AND METHODS: 180 human enamel/dentin specimens were utilized. Enamel buccal surfaces were etched with phosphoric-acid then divided into: (EBG) borate glass adhesive group; (ERS) resin-adhesive system group; (EF) fluoride gel 1.23% group, and enamel control (EC) group; followed by bonding to orthodontic-buttons. The dentin specimens were conditioned by EDTA (Ethylene-diamine-tetra-acetic acid) and divided into: (DBG) borate glass resin, (DRS) resin adhesive; (DDA) group had a dentin-desensitizing agent VivaSens (VivaDent, Liechtenstein) and (DC) control group. The treated enamel/dentin specimens had their SBS to composite. The enamel/dentin specimens were exposed to 1% citric acid (18 min). Enamel/dentin specimens were examined by (SEM/EDS) scanning-electron-microscope equipped with electron-dispersive-spectroscopy and (FTIR/ATR). Analysis-of-Variance (ANOVA) was used to compare the SBS and Wilcoxon-signed-rank test was used to compare the enamel/dentin areas protected by the applied agents before/after erosion (p = 0.05). RESULTS: There was no significance difference in SBS among all groups except for (DDA) group that showed significant decrease p < 0.05. (EBG) and (DBG) groups were the only groups significantly protected enamel and dentin from erosion p < 0.05. FTIR/ATR showed that erosion altered the chemical structure of (DRS), (DDA), and (DC) groups but did not affect the other enamel/dentin groups. Degree of conversion of the borate-adhesive system was acceptable. CONCLUSION: The Borate adhesive system released calcium and phosphate compounds that decreased the erosive activity of the citric acid resulting in protecting simulated dentin-hypersensitive areas and enamel from erosion without affecting the SBS to resin-composite. CLINICAL SIGNIFICANCE: A Borate adhesive system can be adopted as a therapeutic agent in a fully integrated program for protecting dentin-hypersensitive areas and in enamel next to orthodontic fixed appliances.

The effects of borate minerals on the synthesis of nucleic acid bases, amino acids and biogenic carboxylic acids from formamide.

The thermal condensation of formamide in the presence of mineral borates is reported. The products afforded are precursors of nucleic acids, amino acids derivatives and carboxylic acids. The efficiency and the selectivity of the reaction was studied in relation to the elemental composition of the 18 minerals analyzed. The possibility of synthesizing at the same time building blocks of both genetic and metabolic apparatuses, along with the production of amino acids, highlights the interest of the formamide/borate system in prebiotic chemistry.

Colloid-enhanced ultrafiltration in removal of traces amounts of borates from water.

The use of colloid-enhanced ultrafiltration for boron removal from water is investigated. Biodegradable surfactant, 1,4-sorbitol oleate, was applied to obtain micelles and high molecular weight chitosan to reinforce their stability. Two kind of membranes were compared: neat porous polysulfone membrane and charged porous sulfonated polysylfone membrane; both with similar average pore diameter of 5 nm. The studies revealed that two key factors affect the boron rejection: presence of surfactant in the colloidal mixture and a repulsion effect of sulfone groups on the membrane surface. Both have a positive effect on boron removal.

Boron concentration in water, sediment and different organisms around large borate deposits of Turkey.

Boron is an essential nutrient for plants and an essential element for many organisms, but can be toxic to aquatic and terrestrial organisms above certain concentrations. The aim of this research was to determine boron concentrations in water, sediment and biotic samples (Gammaridae spp.-Crustacea, Helix sp.-Gastropoda, Donax sp.-Bivalvia, Helobdella sp.-Hirudinae, Ephemeroptera nymph, Chrinomidae larvae, Tipulidae larvae-Insecta, Rana sp.-Amphibia, Natrix sp.-Serpentes, fish sample Leiscus cephalus (Linnaeus, 1758) and leaves of Salix sp.-Salicacea from Seydi Stream (Kirka-Eskisehir). Our results have shown that boron concentrations of the Seydi Stream water is higher than the Turkish Environmental Guidelines standard (>1 mg L(-1)) and in Europe (mean values typically below 0.6 mg L(-1)).

Cellulose-based fluorescent sensor for visual and versatile detection of amines and anions.

It is practical and challenging to construct ultrasensitive and multi-responsive sensors for visual and real-time monitoring of the environment. Herein, a cellulose-based multi-responsive fluorescent sensor (Phen-MDI-CA) is fabricated, and realizes a visual and ultrasensitive detection of not only various amines but also three anions based on the change of the fluorescence and/or visible colors. Once exposure to various amines in both the solution and vapor state, the Phen-MDI-CA solution and test paper exhibit different fluorescence colors, which can be used to distinguish triethylamine, ethylenediamine, methylamine, aniline, hydrazine and pyrrolidine from other amines. Moreover, via combining the Phen-MDI-CA with the Phen-MDI-CA/malachite green ratiometric system, phosphate (PO43-), carbonate (CO32-) and borate (B4O72-) can be visually and accurately recognized depending on the change of the visible and fluorescence colors. In fluorescent mode, the LOD for B4O72-, PO43- and CO32- ions is as low as 0.18 nmol, 0.69 nmol and 0.86 nmol, respectively. Significantly, the Phen-MDI-CA can readily make a qualitative and quantitative detection of B4O72-, PO43- and CO32- anions in the mixture of anions. The state-of-the-art responsive behavior of Phen-MDI-CA originates from the amplification effect of cellulose polymer chain and the differentiated interactions between the sensor and analytes.

A capillary zone electrophoretic method for simultaneous determination of seven drugs in pharmaceuticals and in human urine.

A simple, sensitive, and novel method has been developed and validated for the separation and simultaneous quantitation of seven structurally different drugs-pipemidic acid and ofloxacin quinolone antibiotics, pseudoephedrine decongestant, piroxicam anti-inflammatory, thiamin, pyridoxine, and cobalamin-in a mixture by capillary zone electrophoresis. Factors affecting the separation were pH, concentration of buffer, and applied voltage. Separation was carried out in < 9 min with a 50 mM sodium tetraborate buffer, pH 10, and an applied voltage of 30 kV in an uncoated silica capillary tube. The carrier electrolyte gave baseline separation with good resolution, reproducibility, and accuracy. Calibration plots were linear over at least three orders of magnitude of analyte concentrations, and the lower LODs were within the range of 1-5 microg/mL. Detection was performed by UV absorbance at 230 nm. The method was validated for the analysis of drugs in pharmaceutical preparations and in urine samples with RSD of 0.5-2.4% and recovery of > 99%.

Effect of imidazolium-based ionic liquids on the photosynthetic activity and growth rate of Selenastrum capricornutum.

Ionic liquids (ILs) are low-melting organic salts that are being researched intensively as possible environmentally friendly replacements for volatile organic solvents. Despite their nonmeasurable vapor pressure, some quantities of ILs soon will be present in effluent discharges because solubility of ILs in water is small, but far from negligible. Therefore, it is important to understand how ILs will influence aquatic ecosystems. In the present study, the toxic effects of imidazolium-based ILs (1-butyl-3-methylimidazolium cation associated with bromide [BMIM] [Br] and tetrafluoroborate [BMIM] [BF4]) to the freshwater green alga Selenastrum capricornutum were investigated. Two approaches were followed to quantify toxicity of these compounds: Analyses of photosynthetic activity and cell proliferation. The obtained data showed that the relative declines of growth rates generally were more pronounced than those of photosynthetic activity. The ecotoxicity of a range of common organic solvents also was examined. It was revealed that both imidazolium-based ILs studied were some orders of magnitude more toxic than methanol, isopropanol, and dimethylformamide. In addition, with respect to IL incorporating perfluorinated anion, EC50 values (concentrations which lead to a 50% reduction of the exposed organisms relative to control) of the previously prepared stock solution were significantly lower compared to those of the freshly made one. This might be due to hydrolytic effects of [BMIM][BF4] leading to fluoride formation, which was confirmed by ion chromatography analysis. This indicates that, after ILs are discharged into the aqueous system, they can become more toxic than expected by laboratory data with fresh ILs.

Exploration and application of a highly sensitive bis(salamo)-based fluorescent sensor for B4O72- in water-containing systems and living cells.

A highly selective fluorescent sensor H4L based on a bis(salamo)-type compound with two N2O2 chelating moieties as ionophore was successfully developed. Sensor H4L was found to have excellent selectivity for B4O72- over many other anions (Br-, CI-, CN-, CO32-, HCO3-, H2PO4-, HSO4-, NO3-, OAc-, S2O3-, SCN-, SO42-, Hcy (homocysteine) and H2O2), and it exhibited an approximately 150-fold enhancement of the fluorescence response to B4O72- in Tris-HCl buffer (DMF/H2O = 9:1, v/v, pH = 7) solutions. Significantly, its fluorescence intensity was enhanced in a linear fashion with increasing concentrations of B4O72-. The detection limit of sensor H4L towards B4O72- was 8.61 × 10-7 M. The test strips could conveniently, efficiently and simply detect B4O72- ions in Tris-HCl buffer (DMF/H2O = 9:1, v/v, pH = 7) solutions. Furthermore, sensor H4L showed excellent membrane permeability in living cells, and it was successfully used to monitor intracellular B4O72- by confocal luminescence imaging.

Biosensors for the Detection and Quantification of AI-2 Class Quorum-Sensing Compounds.

Intercellular small-molecular-weight signaling molecules modulate a variety of biological functions in bacteria. One of the more complex behaviors mediated by intercellular signaling molecules is the suite of activities regulated by quorum-sensing molecules. These molecules mediate a variety of population-dependent responses including the expression of genes that regulate bioluminescence, type III secretion, siderophore production, colony morphology, biofilm formation, and metalloprotease production. Given their central role in regulating these responses, the detection and quantification of QS molecules have important practical implications. Until recently, the detection of QS molecules from Gram-negative bacteria has relied primarily on bacterial reporter systems. These bioassays though immensely useful are subject to interference by compounds that affect bacterial growth and metabolism. In addition, the reporter response is highly dependent on culture age and cell population density. To overcome such limitations, we developed an in vitro protein-based assay system for the rapid detection and quantification of the furanosyl borate diester (BAI-2) subclass of autoinducer-2 (AI-2) QS molecules. The biosensor is based on the interaction of BAI-2 with the Vibrio harveyi QS receptor LuxP. Conformation changes associated with BAI-2 binding to the LuxP receptor change the orientation of cyan and yellow variants of GFP (CFP and YFP) fused to the N- and C-termini, respectively, of the LuxP receptor. LuxP-BAI2 binding induces changes in fluorescence resonance energy transfer (FRET) between CFP and YFP, whose magnitude of change is ligand concentration dependent. Ligand-insensitive LuxP mutant FRET protein sensors were also developed for use as control biosensors. The FRET-based BAI-2 biosensor responds selectively to both synthetic and biologically derived BAI-2 compounds. This report describes the use of the LuxP-FRET biosensor for the detection and quantification of BAI-2.

Simultaneous determination of borate, chloride and molybdate in pyrohydrolysis distillates of plant and soil samples by ion chromatography.

Determination of concentrations of micronutrients in plant samples is important in order to assess the growth and quality of plants. An ion chromatography (IC) method was developed for the simultaneous determination of B, Cl and Mo (micronutrients present in their anionic form in aqueous samples) using a gradient elution with d-mannitol and NaOH. Despite their different chemical nature, these elements could be separated from the matrix by employing pyrohydrolysis. IC was employed for their sequential determination from single aliquot injection into the IC column. It was observed that the optimised procedures developed earlier in our laboratory for the separation of B and halogens using d-Mannitol-NaOH or bicarbonate eluents could not be extended to B-Mo-Cl separation. The concentration levels of d-mannitol in the eluent required for separation of boron impeded the conductivity detection of Mo and the peak sensitivity was seen to be critically dependent on d-mannitol concentration in the eluent. In addition, d-mannitol in NaOH eluent altered the retention times of analytes (B, F-, Cl-, NO3-, SO42-and MoO42-) which were not observed in the case of bicarbonate eluent. The current study deals with the investigation on the influence of d-mannitol on the molybdate as well as its role on the retention time. Formation of Mo-mannitol complex at different pH conditions and de-protonation of mannitol were correlated to the observed effects. Based on the observations, a gradient elution method was proposed for the simultaneous separation and determination of B, Cl and Mo in the pyrohydrolysis distillates of plant samples. The method was calibrated for B (0.05-1 mg/L), Cl (0.1-10 mg/L) and Mo (0.5-10 mg/L) and the linear regression coefficients obtained were 0.9992, 0.9998 and 0.997 respectively. The limit of detection (LOD) for B, Cl and Mo was calculated to be 19, 23 and 96 µg/L, respectively. The developed IC method after pyrohydrolytic separation of B, Cl and Mo was successfully applied for the analysis of real samples.

Heavy metal pollution and spatial distribution in surface sediments of Mustafakemalpasa stream located in the world's largest borate basin (Turkey).

Mining activities in addition to the geology of Mustafakemalpasa catchment have for long been linked to its deteriorating water and sediment quality. This study assessed contamination levels of heavy metals and other major elements (Pb, As, B, Cd, Zn, Cr, Mo, Co, Ni, Cu, and Ag) in surface sediments of the area, and identified possible pollution sources. Sediment quality indicators, such as contamination factor (CF), enrichment factor (EF), geo-accumulation index (Igeo) and sediment quality guidelines were used, in addition to multivariate statistical technics; Pearson Correlation Matrix (PCM), Principal Component Analysis (PCA) and Hierarchical Cluster Analysis (HCA). The highest contamination (annual average > 110 mg kg-1) was revealed by B, Cr, Ni, Zn and As. Moreover, As, Cd and Ni levels exceeded their respective probable effect concentrations (PEC), posing a potential negative impact to biota. The highest Igeo values were recorded for Cr, B, Ni, As and Zn, and occurred near urban settlements and mining sites, particularly of coal and chromium. The present study also suggests use of site rank index (SRI) as an alternative to pollution load index (PLI), since the former is derived from the data of interest and eliminates arbitrary classifications. The sources of heavy metals in the sediments were attributed to fly ashes of coal-powered plants, urban waste leachate and weathering of sulfide ore minerals for Pb, Zn and Cu; urban-industrial wastes and mining wastes for Ni. Although Cr, As, Cd and B were ascribed to natural occurrence, their presences in river sediment is accelerated by mining.

Determination of kava lactones and flavonoid glycoside in Scorzonera austriaca by capillary zone electrophoresis.

A capillary zone electrophoretic method has been developed for the quantitative analysis of three active comppounds, 12-hydroxy-desmethoxyyangonin (HD), 12-beta-d-glucopyranoside-desmethoxyyangonin (GD) and luteolin 3'-(6-E-p-coumaroyl-beta-d-glucopyranoside) (LG) in Scorzonera austriaca with UV detection at 254 nm. The applied voltage was 25 kV and the capillary temperature was kept constant at 25 degrees C. The effect of buffer pH, the concentration of electrolyte and organic modifier on migration were studied systematically. Optimum separation was achieved with 20 mM borate buffer at pH 10.00 containing 10% (v/v) methanol. Daphnetin was used as internal standard for quantification. Regression equations revealed good linear relationship between the ratios of the peak area of each compound and its the ratios of concentration. All the correlation coefficients were higher than 0.9990. The relative standard deviations of migration time and the peak area were <1.46% and 5.13% (inter-day), and <1.65% and 5.16% (intra-day), respectively. The contents of the three compounds in S. austriaca were successfully determined with satisfactory repeatability and recovery.

Quantifying the mode II critical strain energy release rate of borate bioactive glass coatings on Ti6Al4V substrates.

Bioactive glasses have been used as coatings for biomedical implants because they can be formulated to promote osseointegration, antibacterial behavior, bone formation, and tissue healing through the incorporation and subsequent release of certain ions. However, shear loading on coated implants has been reported to cause the delamination and loosening of such coatings. This work uses a recently developed fracture mechanics testing methodology to quantify the critical strain energy release rate under nearly pure mode II conditions, GIIC, of a series of borate-based glass coating/Ti6Al4V alloy substrate systems. Incorporating increasing amounts of SrCO3 in the glass composition was found to increase the GIIC almost twofold, from 25.3 to 46.9J/m2. The magnitude and distribution of residual stresses in the coating were quantified, and it was found that the residual stresses in all cases distributed uniformly over the cross section of the coating. The crack was driven towards, but not into, the glass/Ti6Al4V substrate interface due to the shear loading. This implied that the interface had a higher fracture toughness than the coating itself.