Objective:To evaluate the alteration of chemical behavior of L-ascorbic acid(vitamin C) with metal ion(nickel) at different pH solutions in vitro.Methods:Spectra of pure aqueous solution of L-ascorbic acid(E mark) com...Objective:To evaluate the alteration of chemical behavior of L-ascorbic acid(vitamin C) with metal ion(nickel) at different pH solutions in vitro.Methods:Spectra of pure aqueous solution of L-ascorbic acid(E mark) compound and NiSO_4(H_2O)(sigma USA) were evaluated by UV visible spectrophotometer.Spectral analysis of L-ascorbic acid and nickel at various pH(2.0, 7.0,7.4 and 8.6) at room temperature of 29℃ was recorded.In this special analysis,combined solution of L-ascorbic acid and nickel sulfate at different pH was also recorded.Results:The result revealed that λ_(max)(peak wavelength of spectra) of L-ascorbic acid at pH 2.0 was 289.0 run whereas at neutral pH 7.0,λ_(max) was 29S.4 run.In alkaline pH 8.6,λ_(max) was 295.4 nm and at pH 7.4 the λ_(max) of L-ascorbic acid remained the same as 295.4 nm.Nickel solution at acidic pH 2.0 was 394.5 nm,whereas at neutral pH 7.0 and pH 7.4 were the same as 394.5 nm.But at alkaline pH 8.6,λ_(max) value of nickel sulfate became 392.0 nm.The combined solution of L-ascorbic acid and nickel sulfate(6 mg/mL each) at pH 2.0 showed 292.5 nm and 392.5 nm,respectively whereas at pH 7.0,L-ascorbic acid showed 296.5 nm and nickel sulfate showed 391.5 nm.At pH 7.4,L-ascorbic acid showed 297.0 nm and nickel sulfate showed 394.0 nm in the combined solution whereas at pH 8.6(alkaline) L-ascorbic acid and nickel sulfate were showing 297.0 and 393.5 nm,respectively. Conclusions:Results clearly indicate an altered chemical behavior of L-ascorbic acid either alone or in combination with nickel sulfate in vitro at different pH.Perhaps oxidation of L-ascorbic acid to L-dehydro ascorbic acid via the free radical(HSc*) generation from the reaction of H,ASc + Ni(Ⅱ) is the cause of such alteration of λ_(max),value of L-ascorbic acid in the presence of metal nickel.展开更多
试验旨在使用无记忆效应氢化物发生原子荧光仪测定饲料中汞的含量。采用联合研发的原子荧光光度计,建立一种以水为载流无记忆效应氢化物发生原子荧光法检测饲料中汞的方法。从4种混合酸中优选出HNO3-H2O2(1∶1)作为消解体系,选用2 mL 22...试验旨在使用无记忆效应氢化物发生原子荧光仪测定饲料中汞的含量。采用联合研发的原子荧光光度计,建立一种以水为载流无记忆效应氢化物发生原子荧光法检测饲料中汞的方法。从4种混合酸中优选出HNO3-H2O2(1∶1)作为消解体系,选用2 mL 220 g/L氨基磺酸溶液消除了氮氧化合物的干扰。建立的方法在0.2~1.0μg/L范围内线性良好,相关系数r=0.999 6,检出限(n=11)为0.003 1μg/L,相对标准偏差(n=7)为2.28%,加标回收率93%~99%。研究表明,试验所用方法具有灵敏度高、准确高效等优点,可实现饲料中汞含量的快速检测。展开更多
Fishes are excellent markers of the extent of pollution from heavy metals in aquatic environments given that they are found at various levels of the food chain.This study aimed to investigate the bioaccumulation of he...Fishes are excellent markers of the extent of pollution from heavy metals in aquatic environments given that they are found at various levels of the food chain.This study aimed to investigate the bioaccumulation of heavy metals(Zn,Pb,Cd,As,and Hg)as well as the activity of delta-aminolevulinic acid dehydratase(δ-ALA-D)in the livers of cat fishes(Clarias gariepinus)collected from three rivers(Donga,Ibi and Gindin-Dorowa)in Taraba State,Nigeria.The concentrations of heavy metals in the liver tissues were determined using an atomic absorption spectrophotometer in accordance with the method of AOAC(2019),while theδ-ALA-D activity was assayed using the method of Sassa(1982).Results revealed that only Zn and As were present in the liver samples from the three rivers.Pb was found only in the liver from Gindin-Dorowa at the concentration of 0.0012mg/kg which is not significant(P<0.05)when compared with other locations,while Hg and Cd were absent in all the liver samples.The liver sample from Gindin-Dorowa had the highest concentration of Zn(4.2500 mg/kg),followed by Ibi(3.2067 mg/kg),and Donga having the least(2.5500 mg/kg),which were all substantially(P<0.05)different from one another.However,there was no significant(P<0.05)difference in the As composition of liver from Donga(0.0013 mg/kg),Ibi(0.0012 mg/kg)and Gindin-Dorowa(0.0010 mg/kg).The result ofδ-ALA-D activity showed that the highest enzymatic activity was found in the liver sample from Donga which has the least Zn and no Pb content,followed by Ibi sample.This validates the report that heavy metals impairδ-ALA-D activity.Nonetheless,the concentrations of all metals in fish livers from all regions do not exceed the acceptable limits set by international law,making them safe for human consumption and possibly not having a negative impact on public health.Since there is little or no industrial activity in the studied locations,these levels may be consequent to low anthropogenic inputs.The current situation should be safeguarded to prevent pollution of the river’s aquatic biota in the near future,and more appropriate steps should be made to guarantee higher fish quality and life in the rivers.展开更多
基金financially supported by Defence Institute ofPhysiology and Allied Sciences,Government of India,New Delhi[grant No.TC/292/TASK-116(KDS)/DIPAS/2006]
文摘Objective:To evaluate the alteration of chemical behavior of L-ascorbic acid(vitamin C) with metal ion(nickel) at different pH solutions in vitro.Methods:Spectra of pure aqueous solution of L-ascorbic acid(E mark) compound and NiSO_4(H_2O)(sigma USA) were evaluated by UV visible spectrophotometer.Spectral analysis of L-ascorbic acid and nickel at various pH(2.0, 7.0,7.4 and 8.6) at room temperature of 29℃ was recorded.In this special analysis,combined solution of L-ascorbic acid and nickel sulfate at different pH was also recorded.Results:The result revealed that λ_(max)(peak wavelength of spectra) of L-ascorbic acid at pH 2.0 was 289.0 run whereas at neutral pH 7.0,λ_(max) was 29S.4 run.In alkaline pH 8.6,λ_(max) was 295.4 nm and at pH 7.4 the λ_(max) of L-ascorbic acid remained the same as 295.4 nm.Nickel solution at acidic pH 2.0 was 394.5 nm,whereas at neutral pH 7.0 and pH 7.4 were the same as 394.5 nm.But at alkaline pH 8.6,λ_(max) value of nickel sulfate became 392.0 nm.The combined solution of L-ascorbic acid and nickel sulfate(6 mg/mL each) at pH 2.0 showed 292.5 nm and 392.5 nm,respectively whereas at pH 7.0,L-ascorbic acid showed 296.5 nm and nickel sulfate showed 391.5 nm.At pH 7.4,L-ascorbic acid showed 297.0 nm and nickel sulfate showed 394.0 nm in the combined solution whereas at pH 8.6(alkaline) L-ascorbic acid and nickel sulfate were showing 297.0 and 393.5 nm,respectively. Conclusions:Results clearly indicate an altered chemical behavior of L-ascorbic acid either alone or in combination with nickel sulfate in vitro at different pH.Perhaps oxidation of L-ascorbic acid to L-dehydro ascorbic acid via the free radical(HSc*) generation from the reaction of H,ASc + Ni(Ⅱ) is the cause of such alteration of λ_(max),value of L-ascorbic acid in the presence of metal nickel.
文摘Fishes are excellent markers of the extent of pollution from heavy metals in aquatic environments given that they are found at various levels of the food chain.This study aimed to investigate the bioaccumulation of heavy metals(Zn,Pb,Cd,As,and Hg)as well as the activity of delta-aminolevulinic acid dehydratase(δ-ALA-D)in the livers of cat fishes(Clarias gariepinus)collected from three rivers(Donga,Ibi and Gindin-Dorowa)in Taraba State,Nigeria.The concentrations of heavy metals in the liver tissues were determined using an atomic absorption spectrophotometer in accordance with the method of AOAC(2019),while theδ-ALA-D activity was assayed using the method of Sassa(1982).Results revealed that only Zn and As were present in the liver samples from the three rivers.Pb was found only in the liver from Gindin-Dorowa at the concentration of 0.0012mg/kg which is not significant(P<0.05)when compared with other locations,while Hg and Cd were absent in all the liver samples.The liver sample from Gindin-Dorowa had the highest concentration of Zn(4.2500 mg/kg),followed by Ibi(3.2067 mg/kg),and Donga having the least(2.5500 mg/kg),which were all substantially(P<0.05)different from one another.However,there was no significant(P<0.05)difference in the As composition of liver from Donga(0.0013 mg/kg),Ibi(0.0012 mg/kg)and Gindin-Dorowa(0.0010 mg/kg).The result ofδ-ALA-D activity showed that the highest enzymatic activity was found in the liver sample from Donga which has the least Zn and no Pb content,followed by Ibi sample.This validates the report that heavy metals impairδ-ALA-D activity.Nonetheless,the concentrations of all metals in fish livers from all regions do not exceed the acceptable limits set by international law,making them safe for human consumption and possibly not having a negative impact on public health.Since there is little or no industrial activity in the studied locations,these levels may be consequent to low anthropogenic inputs.The current situation should be safeguarded to prevent pollution of the river’s aquatic biota in the near future,and more appropriate steps should be made to guarantee higher fish quality and life in the rivers.
