A simple, precise, accurate, and stability-indicating method is developed and validated for analysis of tetrahydrozoline hydrochloride in eye drop formulations. Separation was achieved on a reversed-phase C8 column (1...A simple, precise, accurate, and stability-indicating method is developed and validated for analysis of tetrahydrozoline hydrochloride in eye drop formulations. Separation was achieved on a reversed-phase C8 column (125 mm 4.6 mm i.d., 5 mm) using a mobile phase consisting of acetonitrile/phosphate buffer of pH 3.0 (20:80, v/v) at a flow rate of 1.0 mL/min and UV detection at 240 nm. This method is validated according to United States Pharmacopeia requirements for new methods, which include accuracy, precision, selectivity, robustness, and linearity and range. This method shows enough selectivity, accuracy, precision, and linearity and range to satisfy Federal Drug Administration/International Conference on Harmonization regulatory requirements. The current method demonstrates good linearity over the range of 0.025–0.075 mg/mL of tetrahydrozoline with r2 0.999. The average recovery of the method is 100.8% with a relative standard deviation of 0.47%. The degree of reproducibility of the results obtained as a result of small deliberate variations in the method parameters and by changing analytical operators has proven that the method is robust and rugged.展开更多
Heavy metal contamination of the groundwater of south West Bank in Palestine was assessed. The groundwater samples were analyzed for different trace heavy metals (Tl, Pb, Bi, Cr, Mn, Co, Ni, Cu, Zn, Mo, Ag, and Cd), a...Heavy metal contamination of the groundwater of south West Bank in Palestine was assessed. The groundwater samples were analyzed for different trace heavy metals (Tl, Pb, Bi, Cr, Mn, Co, Ni, Cu, Zn, Mo, Ag, and Cd), and Al content by ICP/MS. This study was conducted to determine the water quality of ground water which is used for drinking in the study area. Water samples from ten groundwater wells were obtained in four different dates of the year (October 2012, November 2012, March 2013, and April 2013). Three water samples were obtained from each well for each sampling date. A total of 120 water samples were collected from the ten wells. The samples were analyzed for their pH, electrical conductivity, total dissolved solids, and different trace metals content. The pH, electrical conductivity, and total dissolved solids of all water samples were found to be within the US Environmental protection Agency limits. Results showed that Pb, Al, Cr, Co, Ni, Cu, Zn, and Mo were detected in all water samples analyzed in this study, while Tl, Bi, Mn, Ag, and Cd were detected in 80%, 88%, 90%, 75%, and 95% of the water samples analyzed in this study, respectively. In general, 93% of all samples analyzed contained one or more of the 13 metals studied each in varying concentration. Furthermore, results showed that the concentration of Cr, Mn, Ni, Cu, Zn, and Mo is within the allowed WHO limits in drinking water. However the concentration of Pb Cd, and Al are found to be higher than the allowed WHO limits in 40%, 8%, and 33% of the water samples analyzed in this study, respectively. Statistical analyses showed that concentrations of the metals studied in this study vary significantly between the ten ground water wells, indicating that the wells analyzed in this study is different from each other in terms of heavy metal content. Additionally, from the statistical results obtained, it was found that there is a significant difference in the concentration of the metals in each well for the four sampling times (October 2012, November 2012, March 2013, and April 2013), denoting that metal concentration in the wells vary significantly with sampling time. The results obtained from this study suggest a possible risk to the population of the study area given the toxicity of these metals, and the fact that for many people in the study area, ground water is a main source of their water supply.展开更多
In previous work we have developed a dicarboxylate functionalized polymer that demonstrated chemical sensing. It showed good response to pH changes as well as to varying concentrations of copper and calcium ions. Our ...In previous work we have developed a dicarboxylate functionalized polymer that demonstrated chemical sensing. It showed good response to pH changes as well as to varying concentrations of copper and calcium ions. Our recent in-vest- tigations showed interesting results upon testing the functionalized sensing polymer on heavy metals. This sensor is composed of microspheres of polyvinyl benzyl malonate lightly-cross-linked with divinyl benzene dispersed in a hydrogel membrane. The response of the optical sensor is based on the interaction between the metal cations with the deprotonated functional group. The polymer, thus, undergoes shrinking as a result of neutralization of adjacent negative charges on the back-bone of the polymer. This causes significant changes in the optical properties of the sensing element. The optical changes were measured as absorbance vs. wavelength as the sensing membrane is exposed to solutions of varying concentrations of heavy metal ions. The sensor showed significant increase in absorbance up to a concentration of 5 × 10-3 M to the following metal ions: Ni2+, Zn2+, and Cd2+. Furthermore, the studied capacity of the derivatized microspheres showed close values to Ni2+, Zn2+, Cd2+ (1.20, 1.09, 1.08 mmol/g respectively). These kinds of properly functionalized polymers appear to be suitable, versatile sensing elements for the detection of low concentrations of heavy metal ions. In addition, all of the tested heavy metals showed a similar value of the equilibrium formation constant, (log Kf1 is 2.63). In contrast, the sensor showed no significant response to varying concentrations of K+ and Mg2+ metal ions.展开更多
Ground water samples are collected from south West Bank/Palestine and analyzed for different rare elements (Rb, Zr, U, P, Ti, V), rare earth elements (La, Ce, and Nd), and other common trace metals (Li, Na, Mg, Ca, Sr...Ground water samples are collected from south West Bank/Palestine and analyzed for different rare elements (Rb, Zr, U, P, Ti, V), rare earth elements (La, Ce, and Nd), and other common trace metals (Li, Na, Mg, Ca, Sr, Ba, K, Bi) that most of them usually have no maximum acceptable limits as either they are considered not to be toxic to human health or there is no sufficient data about their toxicity to human health. This study was conducted to determine the water quality of ground water which is used for drinking in the study area. Water samples from ten groundwater wells were obtained in three different dates of the year (November 2012, March 2013, and April 2013). Three water samples were obtained from each well for each sampling date;so a total of 90 water samples were collected from the ten wells. The results obtained from this study suggest a possible risk to the population of the study area given the high concentration of some metals that have no maximum allowed concentration, and the fact that for many people in the study area, ground water is a main source of their water supply.展开更多
Groundwater of North West Bank in Palestine was assessed for pollution with trace metals by ICP/MS. The samples were analysed for their pH, electrical conductivity, total dissolved solids, and different trace metals c...Groundwater of North West Bank in Palestine was assessed for pollution with trace metals by ICP/MS. The samples were analysed for their pH, electrical conductivity, total dissolved solids, and different trace metals content. The pH, electrical conductivity, and total dissolved solids of all water samples were found to be within the US Environmental protection Agency limits. Results showed that the concentration of nine trace metals (Cr, Mn, Ni, Cu, Zn, Mo, Pb, Cd, and Al) is within the WHO limits in drinking water (50, 500, 20, 2000, 3000, 70, 10, 3, and 200 ug/L, respectively), however six metals of them (Cr, Mn, Ni, Cu, Mo, and Al) were detected in 100% of the samples, while Pb, Cd, and Zn were detected in 80%, 60%, and 20% of the samples, respectively. On the other hand, Tl which is a very toxic heavy metal with allowed WHO limits of 0.01 - 1 ug/L is detected in 100% of the water samples analysed with a range of 0.02 - 0.12 ug/L. It indicates that such concentration levels of Tl would be harmful to the human being drinking the water. In general, 82% of all samples analysed contained one or more of the 12 metals studied each in varying concentration. Results of this study suggest a possible risk to the people of the study area given the toxicity of heavy metals, and the fact that for many people in the study area, groundwater is a main source of their water supply.展开更多
The effect of using methanol in the flush-solvent bottle of the auto-sampler of Ion Chromatograph on the determination of sulfate ions was studied using AS11-HC 2 mm analytical column. The use of 50% methanol in the f...The effect of using methanol in the flush-solvent bottle of the auto-sampler of Ion Chromatograph on the determination of sulfate ions was studied using AS11-HC 2 mm analytical column. The use of 50% methanol in the flush solvent bottle results in overestimation of sulfate concentration by 18%. However, the use of 10% methanol instead of 50% did not show such error in the determination of sulfate using the same column. Furthermore, the effect of using OnGuard-RP and OnGuard-P cartridges for sample pretreatment on the determination of different anions was also studies using AS14-HC 2 mm analytical column. The results indicate that using OnGuard-RP cartridge caused the concentration of fluoride, bromide, nitrate, phosphate and sulfate ions to be underestimated, whereas the concentration of chloride ions to be overestimated. The error in the determination of fluoride, bromide, nitrate, phosphate sulfate, and chloride was found to be 40.0%, 26.0%, 22.8%, 26.8%, 18.0%, and 25.0% of the certified standard concentration, respectively. It was also found that the use of OnGuard-P cartridge resulted in underestimation of fluoride, chloride, bromide, nitrate, phosphate, and sulfate by 60.0%, 40.0%, 82.0%, 87.2%, 45.2%, and 39.0% of the certified standard concentration, respectively. These findings point out to careful corrections that should be considered in any application of ion chromatography utilizing such sample pretreatment.展开更多
Oxidation is one of the major causes of hamburger deterioration. Antioxidants are used to minimize oxidation process. There is a growing interest in the substitution of synthetic food antioxidants by natural ones from...Oxidation is one of the major causes of hamburger deterioration. Antioxidants are used to minimize oxidation process. There is a growing interest in the substitution of synthetic food antioxidants by natural ones from vegetable sources. In meat industry, sodium erythorbate is antioxidant that is usually used and is an example of chemical antioxidant. Effect of olive leaf extract rich in olenropein on the quality of frozen hamburger was investigated. The objective of this study was to evaluate the usage of oleuropein from olive leaf extract as natural antioxidant in frozen hamburger stored at -12 ℃ compared with sodium erythorbate. Results suggested that olive leaf extracts might be useful to the meat industry as an efficient alternative to synthetic antioxidants by retarding oxidation of hamburger compared with sodium erythorbate 0.5% of olenropein and 0.5% of sodium erythorbate are the best concentrations to be used in frozen hamburger.展开更多
Oleuropein content in olive leaves dried at ambient temperature, and at elevated temperature (50°C) from Palestinian olive trees collected from West Bank in the middle of November was determined by HPLC and co...Oleuropein content in olive leaves dried at ambient temperature, and at elevated temperature (50°C) from Palestinian olive trees collected from West Bank in the middle of November was determined by HPLC and compared to naturally dry olive leaves (collected dry from the tree). Results showed that higher concentration was obtained from olive leaves dried at room temperature (10.0 mg per gram of dry olive leaves), compared to those dried at 50°C (1.7 mg/g), and those that collected dry from the tree (2.5 mg/g). Oleuropein content of dried olive leaves was compared with leaves that chopped and extracted fresh, and results show that fresh leaves showed the lowest oleuropein content (<0.1 mg/g) denoting that drying of leaves is required for high oleuropein recovery.展开更多
文摘A simple, precise, accurate, and stability-indicating method is developed and validated for analysis of tetrahydrozoline hydrochloride in eye drop formulations. Separation was achieved on a reversed-phase C8 column (125 mm 4.6 mm i.d., 5 mm) using a mobile phase consisting of acetonitrile/phosphate buffer of pH 3.0 (20:80, v/v) at a flow rate of 1.0 mL/min and UV detection at 240 nm. This method is validated according to United States Pharmacopeia requirements for new methods, which include accuracy, precision, selectivity, robustness, and linearity and range. This method shows enough selectivity, accuracy, precision, and linearity and range to satisfy Federal Drug Administration/International Conference on Harmonization regulatory requirements. The current method demonstrates good linearity over the range of 0.025–0.075 mg/mL of tetrahydrozoline with r2 0.999. The average recovery of the method is 100.8% with a relative standard deviation of 0.47%. The degree of reproducibility of the results obtained as a result of small deliberate variations in the method parameters and by changing analytical operators has proven that the method is robust and rugged.
文摘Heavy metal contamination of the groundwater of south West Bank in Palestine was assessed. The groundwater samples were analyzed for different trace heavy metals (Tl, Pb, Bi, Cr, Mn, Co, Ni, Cu, Zn, Mo, Ag, and Cd), and Al content by ICP/MS. This study was conducted to determine the water quality of ground water which is used for drinking in the study area. Water samples from ten groundwater wells were obtained in four different dates of the year (October 2012, November 2012, March 2013, and April 2013). Three water samples were obtained from each well for each sampling date. A total of 120 water samples were collected from the ten wells. The samples were analyzed for their pH, electrical conductivity, total dissolved solids, and different trace metals content. The pH, electrical conductivity, and total dissolved solids of all water samples were found to be within the US Environmental protection Agency limits. Results showed that Pb, Al, Cr, Co, Ni, Cu, Zn, and Mo were detected in all water samples analyzed in this study, while Tl, Bi, Mn, Ag, and Cd were detected in 80%, 88%, 90%, 75%, and 95% of the water samples analyzed in this study, respectively. In general, 93% of all samples analyzed contained one or more of the 13 metals studied each in varying concentration. Furthermore, results showed that the concentration of Cr, Mn, Ni, Cu, Zn, and Mo is within the allowed WHO limits in drinking water. However the concentration of Pb Cd, and Al are found to be higher than the allowed WHO limits in 40%, 8%, and 33% of the water samples analyzed in this study, respectively. Statistical analyses showed that concentrations of the metals studied in this study vary significantly between the ten ground water wells, indicating that the wells analyzed in this study is different from each other in terms of heavy metal content. Additionally, from the statistical results obtained, it was found that there is a significant difference in the concentration of the metals in each well for the four sampling times (October 2012, November 2012, March 2013, and April 2013), denoting that metal concentration in the wells vary significantly with sampling time. The results obtained from this study suggest a possible risk to the population of the study area given the toxicity of these metals, and the fact that for many people in the study area, ground water is a main source of their water supply.
文摘In previous work we have developed a dicarboxylate functionalized polymer that demonstrated chemical sensing. It showed good response to pH changes as well as to varying concentrations of copper and calcium ions. Our recent in-vest- tigations showed interesting results upon testing the functionalized sensing polymer on heavy metals. This sensor is composed of microspheres of polyvinyl benzyl malonate lightly-cross-linked with divinyl benzene dispersed in a hydrogel membrane. The response of the optical sensor is based on the interaction between the metal cations with the deprotonated functional group. The polymer, thus, undergoes shrinking as a result of neutralization of adjacent negative charges on the back-bone of the polymer. This causes significant changes in the optical properties of the sensing element. The optical changes were measured as absorbance vs. wavelength as the sensing membrane is exposed to solutions of varying concentrations of heavy metal ions. The sensor showed significant increase in absorbance up to a concentration of 5 × 10-3 M to the following metal ions: Ni2+, Zn2+, and Cd2+. Furthermore, the studied capacity of the derivatized microspheres showed close values to Ni2+, Zn2+, Cd2+ (1.20, 1.09, 1.08 mmol/g respectively). These kinds of properly functionalized polymers appear to be suitable, versatile sensing elements for the detection of low concentrations of heavy metal ions. In addition, all of the tested heavy metals showed a similar value of the equilibrium formation constant, (log Kf1 is 2.63). In contrast, the sensor showed no significant response to varying concentrations of K+ and Mg2+ metal ions.
文摘Ground water samples are collected from south West Bank/Palestine and analyzed for different rare elements (Rb, Zr, U, P, Ti, V), rare earth elements (La, Ce, and Nd), and other common trace metals (Li, Na, Mg, Ca, Sr, Ba, K, Bi) that most of them usually have no maximum acceptable limits as either they are considered not to be toxic to human health or there is no sufficient data about their toxicity to human health. This study was conducted to determine the water quality of ground water which is used for drinking in the study area. Water samples from ten groundwater wells were obtained in three different dates of the year (November 2012, March 2013, and April 2013). Three water samples were obtained from each well for each sampling date;so a total of 90 water samples were collected from the ten wells. The results obtained from this study suggest a possible risk to the population of the study area given the high concentration of some metals that have no maximum allowed concentration, and the fact that for many people in the study area, ground water is a main source of their water supply.
文摘Groundwater of North West Bank in Palestine was assessed for pollution with trace metals by ICP/MS. The samples were analysed for their pH, electrical conductivity, total dissolved solids, and different trace metals content. The pH, electrical conductivity, and total dissolved solids of all water samples were found to be within the US Environmental protection Agency limits. Results showed that the concentration of nine trace metals (Cr, Mn, Ni, Cu, Zn, Mo, Pb, Cd, and Al) is within the WHO limits in drinking water (50, 500, 20, 2000, 3000, 70, 10, 3, and 200 ug/L, respectively), however six metals of them (Cr, Mn, Ni, Cu, Mo, and Al) were detected in 100% of the samples, while Pb, Cd, and Zn were detected in 80%, 60%, and 20% of the samples, respectively. On the other hand, Tl which is a very toxic heavy metal with allowed WHO limits of 0.01 - 1 ug/L is detected in 100% of the water samples analysed with a range of 0.02 - 0.12 ug/L. It indicates that such concentration levels of Tl would be harmful to the human being drinking the water. In general, 82% of all samples analysed contained one or more of the 12 metals studied each in varying concentration. Results of this study suggest a possible risk to the people of the study area given the toxicity of heavy metals, and the fact that for many people in the study area, groundwater is a main source of their water supply.
文摘The effect of using methanol in the flush-solvent bottle of the auto-sampler of Ion Chromatograph on the determination of sulfate ions was studied using AS11-HC 2 mm analytical column. The use of 50% methanol in the flush solvent bottle results in overestimation of sulfate concentration by 18%. However, the use of 10% methanol instead of 50% did not show such error in the determination of sulfate using the same column. Furthermore, the effect of using OnGuard-RP and OnGuard-P cartridges for sample pretreatment on the determination of different anions was also studies using AS14-HC 2 mm analytical column. The results indicate that using OnGuard-RP cartridge caused the concentration of fluoride, bromide, nitrate, phosphate and sulfate ions to be underestimated, whereas the concentration of chloride ions to be overestimated. The error in the determination of fluoride, bromide, nitrate, phosphate sulfate, and chloride was found to be 40.0%, 26.0%, 22.8%, 26.8%, 18.0%, and 25.0% of the certified standard concentration, respectively. It was also found that the use of OnGuard-P cartridge resulted in underestimation of fluoride, chloride, bromide, nitrate, phosphate, and sulfate by 60.0%, 40.0%, 82.0%, 87.2%, 45.2%, and 39.0% of the certified standard concentration, respectively. These findings point out to careful corrections that should be considered in any application of ion chromatography utilizing such sample pretreatment.
文摘Oxidation is one of the major causes of hamburger deterioration. Antioxidants are used to minimize oxidation process. There is a growing interest in the substitution of synthetic food antioxidants by natural ones from vegetable sources. In meat industry, sodium erythorbate is antioxidant that is usually used and is an example of chemical antioxidant. Effect of olive leaf extract rich in olenropein on the quality of frozen hamburger was investigated. The objective of this study was to evaluate the usage of oleuropein from olive leaf extract as natural antioxidant in frozen hamburger stored at -12 ℃ compared with sodium erythorbate. Results suggested that olive leaf extracts might be useful to the meat industry as an efficient alternative to synthetic antioxidants by retarding oxidation of hamburger compared with sodium erythorbate 0.5% of olenropein and 0.5% of sodium erythorbate are the best concentrations to be used in frozen hamburger.
文摘Oleuropein content in olive leaves dried at ambient temperature, and at elevated temperature (50°C) from Palestinian olive trees collected from West Bank in the middle of November was determined by HPLC and compared to naturally dry olive leaves (collected dry from the tree). Results showed that higher concentration was obtained from olive leaves dried at room temperature (10.0 mg per gram of dry olive leaves), compared to those dried at 50°C (1.7 mg/g), and those that collected dry from the tree (2.5 mg/g). Oleuropein content of dried olive leaves was compared with leaves that chopped and extracted fresh, and results show that fresh leaves showed the lowest oleuropein content (<0.1 mg/g) denoting that drying of leaves is required for high oleuropein recovery.
