Spectrophotometric analysis of trichloroethylene in various environmental and biological samples

A simple sensitive extractive spectrophotometric method for determination of trichloroethylene is proposed. Trichloroethylene is treated with pyridine to form glutaconic aldehyde by heterolytic cleavage of the pyridine ring. Glutaconic aldehyde is further coupled with 4-aminoacetanilide to form an orange–red dye which is extractable in 3-methyl-1-butanol. The extracted dye shows absorption maximum at 520 nm. The system obeys Beer’s law in the range of 0.05–0.8 μg mL^?1. Important analytical parameters such as time, temperature, reagent concentration, acidity etc. have been optimized for complete colour reaction. Sandell’s sensitivity and molar absorptivity for the system were found to be 0.001 μg cm^?2 and 1.2 × 10⁵ L mol^?1 cm^?1, respectively. The proposed method is satisfactorily applied to micro-level determination of trichloroethylene in various environmental and biological samples.     

Colorimetric Determination of Seleniumin Various Environmental Samples

A new reagent system using rhodamine‐B dye for the determination of selenium is described. The method is based on the reaction of selenium with acidified potassium iodide to liberate iodine. The liberated iodine bleaches the pink colour rhodamine‐B, which is measured at 555 nm. Beer's law is obeyed over the concentration range of 1–10 μg of selenium final solution volume of 25 mL (0.04–0.4 ppm) and the apparent molar absorptivity and Sandell's sensitivity was found to be 1.96× 10⁵ l mol^?1 cm^?1 and 0.0004 μg cm^?2, respectively. The method is simple, sensitive, and selective and is satisfactorily applied to micro‐level determination of selenium in various environmental and cosmetic samples.     

A Sensitive Spectrophotometric Determination of Nitrite in Water and Soil

A highly sensitive spectrophotometric method for the determination of nitrite in water and soil has been developed. The reaction of nitrite with acidified potassium iodide to liberate iodine which oxidizes leuco‐crystal violet (LCV) to form crystal violet having absorption maxima at 590 nm forms the bases of this method. In aqueous medium the system obeys Beer's law in the range of 0.1 to 1.0 μg per 25 mL (0.004–0.04 ppm), while in an extractive system the range is 0.025–0.25 μg in 100 mL (0.00025–0.0025 ppm). The molar absorptivity and Sandell's sensitivity were found to be 1.54 × 10⁶ 1 mol^?1 cm^?1 and 44 pg cm^?2, respectively.     

Spectrophotometric determination of hydrogen cyanide in air using phloroglucinol

Summary A spectrophotometric determination of hydrogen cyanide in air is described. Hydrogen cyanide from air is collected in dilute sodium hydroxide and then reacted with pyridine forming glutaconic aldehyde. The glutaconic aldehyde thus formed is subsequently coupled with aqueous phloroglucinol solution to form a polymethine red-violet dye having absorbance maxima at 540 nm. The colour system obeys Beer's law in the range of 0.45 to 3.6 mg/m³ of hydrogen cyanide (0.4 to 3.2 g/g). Collection efficiency of absorbing solution, molar absorptivity and Sandell's sensitivity have been evaluated. All other important analytical parameters have been studied and applied for the determination/detection of hydrogen cyanide in air samples and cigarette smoke.     

A sensitive spectrophotometric determination of atrazine in micellar medium and its application in environmental samples

A sensitive analytical procedure based on solid phase extractive-spectrophotometry has been established for the determination of the widely used herbicide atrazine .The method is based on the Konig reaction in which atrazine reacts with pyridine reagent to form a quaternary pyridinium halide, which further forms glutaconic aldehyde in the presence of alkali. Glutaconic aldehyde is subsequently coupled with 4-aminoacetanilide in the micellar medium of anionic surfactant sodium dodecyl sulphate to give a yellow-orange dye. The produced dye was enriched on a C₁₈ cartridge and is measured spectrophotometrically at 460 nm. The sensitivity and selectivity of the method was largely enhanced in the micellar media and SPE on the C₁₈ cartridge and avoids the use of toxic solvents. Beer’s law was obeyed in the range 0.012–0.12 μg mL^?1. Molar absorptivity and Sandell’s sensitivity were found to be 1.52 × 10⁶ L mol^? 1 cm^?1 and 0.0002 μg cm^?2, respectively. The limit of detection and quantification were 0.001 and 0.003 μg mL^?1, respectively. The proposed method was applied successfully for the determination of atrazine in environmental and biological samples with a recovery range of 96–101 %. The method was found to be free from interference of a large number of foreign species. The accuracy and reliability of the method was further established by parallel determination by the reference method, and by recovery studies.     

Colorimetric Determination of Sulphur Dioxide and Sulphites in Various Environmental Samples

Rhodamine‐B has been proposed as a simple and sensitive colorimetric reagent for the estimation of sulphur dioxide in air. The air sample containing sulphur dioxide is passed through the absorbing solution of aqueous potassium iodate and N‐chlorosuccinimide to liberate iodine. The liberated iodine bleaches the pinkish red coloured rhodamine‐B dye, which measured at 555 nm. Beer's law was obeyed in the range of 0.5–5.0 μg, of sulphite per 25 mL (0.02–0.2 ppm) equivalent to 0.4–4.0 μg of sulphur dioxide (0.016–0.16 ppm). The molar absorptivity and Sandell's sensitivity were found to be 4.56 × 10⁵ l mol^?1 cm^?1 and 0.00017 μg cm^?2, respectively. The method has been suitably modified and successfully applied to the determination of sulphites in water after liberation of sulphur dioxide in acidic medium.     

Spectrophotometric method for determination of atrazine and its application to commercial formulations and real samples

A simple sensitive spectrophotometric method has been developed for the determination of atrazine in herbicide formulations and real samples. The method was based on the reaction of atrazine with pyridine to form a quaternary halide which in the presence of alkali forms a carbinol base. The heterocyclic ring of the carbinol base breaks and forms the glutaconic dialdehyde. The glutaconic dialdehyde group was coupled with sulfanilic acid to form a yellow coloured product having λ _max 450 nm or coupled with aniline to form a orange red coloured product having λ _max 480 nm. The Beer's law was obeyed over the range from 0.1 to 25 µg mL^?1 and molar absorptivity 1.5 × 10⁴ L mol^?1 cm^?1 for sulfanilic acid, and from 0.08 to 12 µg mL^?1 and molar absorptivity 1.3 × 10⁴ L mol^?1 cm^?1 for aniline were observed. The reaction conditions and other analytical parameters were optimised. The proposed method has been successfully applied for the analysis of commercial formulations and real samples.     

Synthesis of New Reagent Benzyloxybenzaldehydethiosemicarbazone (BBTSC): Selective,Sensitive and Extractive Spectrophotometric Determination of Pd(II) in Water Samples and Synthetic Mixtures

A new reagent, benzyloxybenzaldehydethiosemicarbazone (BBTSC) was synthesized and a new method was developed for the simple, highly selective and extractive spectrophotometric determination of palladium(II) with BBTSC at wave length 365 nm. The metal ion formed a yellow colored complex with BBTSC in acetate buffer of pH 5.0, which was easily extractable into cyclohexanol with 1:1 (Metal: Ligand) composition. The method obeys Beer's law in the range of 5–60 ppm. The molar absorptivity and Sandell's sensitivity were found to be 0.4 × 10⁴ Lt. mol^?1 cm^?1 and 0.02661 μg cm^?2, respectively. The correlation co‐efficient of the Pd(II)‐BBTSC complex was 0.9657, which indicated an excellent linearity between the two variables. The repeatability of the method was checked by finding the relative standard deviation (RSD) (n = 10), which was 0.321% and its detection limit 0.016875 μg.mL^?1. The instability constant of the method was calculated by Asmus' method as 3.5714 × 10^?4. The interfering effect of various cations and anions were also studied. The proposed method was successfully applied for the determination of palladium(II) in synthetic and water samples. The results were compared with those obtained using an atomic absorption spectrophotometer, testing the validity of the method.     

Extraction,Spectrophotometric and Atomic Absorption Spectrophotometric Determination of Molybdenum with Caffeic Acid and Application in High Purity Grade Steel and Environmental Samples

Abstract

A new selective and sensitive method for extraction of yellow Mo (VI)-caffeic acid complex with a liquid ion exchanger, Aliquat 336 from 4.0 pH, and spectrophotometric determination of molybdenum in trace amounts is described. the molar absorptivity of the complex is 1.1 × 10⁵ 1 mol^?1 cm^?1 at 340 nm and the colour system obeys Beer's law in the range 0.04–0.99 ppm of Mo(VI). the molybdenum is also determined with AAS and the method is applied for its determination in steel and environmental samples.     

Analytical Applications of 2,6‐Diacetylpyridine‐bis‐4‐phenyl‐3‐thiosemicarbazone (2,6‐DAPBPTSC): Determination of Cd(II) in Foods and Water Samples

To the determination of trace amount of Cd(II) present in food and water samples, a selective and extractive spectrophotometric method were developed with 2,6‐diacetylpyridine‐bis‐4‐phenyl‐3‐thiosemicarbazone as a complexing agent. The yellowish orange colored metal complex, Cd(II)‐2,6‐DAPBPTSC with 1:1 (M:L) composition was extracted in to cyclohexanol at pH 9.5 and was shows maximum absorbance at λ_max 390 nm. This method obeys Beer's law in the range of 1.12‐11.25 ppm with 0.972 correlation coefficient of Cd(II)‐2,6‐DAPBPTSC complex, which is indicates linearity between the two variables. The molar absorptivity and sandell's sensitivity were found to be 6.088 × 10⁴ L mol^?1 cm^?1 and 0.0018 μg cm^?2, respectively. The instability constant calculated from Asmus' method (1.447 × 10^?4)at room temperature. The precision and accuracy of the method were checked by relative standard deviation (n = 5), 0.929 and its detection limit, 0.0060 μg mL^?1. The interfering effects of various cations and anions were also studied. The proposed method was successfully applied to the determination of Cd(II) in foods and water samples, and was evaluated its performance in terms of Student ‘t’ test and Variance ‘f’ test, which indicates the significance of present method. The inter comparison of the experimental values, using atomic absorption spectrometer (AAS), was also repoted.     

Liquid-Liquid Extraction,Photometric and Atomic Absorption Spectrophotometric Determination of Mercury

Abstract

A selective and sensitive spectrophotometric and atomic absorption spectrophotometric method is developed for the determination of traces of mercury with N-phenylcinnamohydroxamic acid (PCHA) in the environment. Mercury is extracted into a chloroform solution of PCHA at pH 8.5-10.0 and determined by AAS. The mercury hydroxamate binary complex is yellow in colour having a maximum absorbance at 390 nm and molar absorptivity 4.3 × 10³ 1 mol^?1 cm^?1, sandell sensitivity 0.0466 μg/cm². The ternary system using 1-(2-pyridylazo)-2-naphthol has molar absorptivity 8.82 × 10³ 1 mol^?1 cm^?1 at 550nm, sandell sensitivity 0.0228 μ/cm². Beer's law is obeyed in the concentration range of 2.37-38.0 ppm and 0.80-19.5 ppm of mercury for binary and ternary system, respectively. The extraction of Hg-PCHA binary system is studied with a liquid cation exchanger, bis-(2-ethyl hexyl) phosphoric acid (HDEHP) and found to have better selectivity than Hg-PCHA-PAN system. The molar absorptivity of the Hg-PCHA-HDEHP system is 8.82 × 10³ 1 mol^?1 cm^?1 at 390 nm and Beer's law is obeyed in the concentration range of 0.47-20 ppm of mercury.

The present method is applied to the determination of mercury in eye drops, aurvedic drugs and environmental samples.     

Synthesis of New Reagent 2,6‐Diacetylpyridine Bis‐4‐Phenyl‐3‐Thiosemicarbazone (2,6‐DAPBPTSC): Selective,Sensitive and Extractive Spectrophotometric Determination of Co(II) in Vegetable,Soil, Pharmaceutical and Alloy Samples

New synthesized reagent 2,6‐diacetylpyridine bis‐4‐phenyl‐3‐thiosemicarbazone (2,6‐DAPBPTSC) is proposed as a sensitive and selective analytical reagent for the extractive spectrophotometric determination of cobalt(II). Cobalt(II) forms a reddish brown colored complex with 2,6‐DAPBPTSC, which is extracted into isoamylalcohol, under optimum conditions. The maximum absorption of the isoamylalcohol extract is measured at 400 nm. Beer's law is applied in the range 0.6‐6.0 ppm of cobalt(II). The molar absorptivity and Sandell's sensitivity of the complex is calculated as 2.2 × 10⁴ L mol^?1 cm^?1 and 2.68 × 10^?3 μg cm^?2, respectively. An adequate linearity with a correlation coefficient value of 0.969 is obtained for the Co(II)‐2,6‐DAPBPTSC complex. The instability constant of the complex, calculated from Asmus' method is 3.75 × 10^?4 The precision and accuracy of the method is checked with calculation of relative standard deviation (n = 5), 0.388 and the detection limit a value is 0.0028 μg mL^?1. The method is successfully employed for the determination of cobalt(II) in real samples, such as vegetables, soil, water samples, standard alloy samples, and the performance of the present method was evaluated in terms of Student ‘t’ test and Variance ‘f’ test, which indicates the significance of the present method is an inter comparison of the experimental values, using atomic absorption spectrometer (AAS).     

Ternary Complex Nickel(II)/3-(4′,5′-Dimethyl-2′-Thiazolylazo)-2,6-Dihydroxybenzoic Acid/Cyanide. Spectrophotometric Determination of Nickel

Abstract

A spectrophotometric method for nickel has been developed based on the formation of a ternary complex in the system Ni(II)/3-(4′,5′-dimethyl-2′-thiazolylazo)-2,6-dihydroxybenzoic acid/cyanide at pH 9.2 (borate buffer), which allows the determination of 0.05–0.47ppm of nickel (ε = 3.53×10⁴ 1.mol^?1. cm^?1) at 538nm. Interferences have been studied and the method applied to the determination of nickel in low alloy steels.     

Trace Spectrophotometric Determination of Dichlorvos using Diphenyl Semicarbazide (DPC) in Environmental and Agricultural Samples

A new and highly sensitive spectrophotometric method is developed for the determination of sub ppm levels of the widely used organophosphorus insecticide dichlorvos. The method is based on alkaline hydrolysis of dichlorvos to dichloroacetaldehyde followed by coupling with diphenyl semicarbazide (DPC) in alkaline medium. The absorption maxima of the wine red dye compound formed is measured at 490 nm. Beer's law is obeyed over the concentration range of 4.3 to 34 μg in a final solution volume of 25 mL (0.18–1.36 ppm). The molar absorptivity, Sandell's sensitivity and correlation coefficient were found to be 2.9 × 10⁵ l mole^?1 cm^?1, 0.013 μg cm^?2 and 0.9999, respectively. The standard deviation and relative standard deviation were found to be ± 0.007 and 1.90%, respectively. The lower limit of detection is 0.04 μg. The method is simple, sensitive and free from interferences of other pesticides and diverse ions. Other organophosphorous pesticides do not interfere with the proposed method. The method has been satisfactorily applied to the determination of dichlorvos in environmental and agricultural samples.     

Novel Dicyanoargentate Polymeric Membrane Sensors for Selective Determination of Cyanide Ions

The construction and general performance characteristics of three novel potentiometric PVC membrane sensors responsive to dicyanoargentate anion are described. The sensors are based on the use of magnesium(II)‐ and iron(II)‐phthalocyanines as neutral ionophores and iron(II)‐bathophenanthroline dicyanoargentate ion‐pair complex as an ion exchanger in plasticized PVC matrices. These sensors exhibit fast, stable and near‐Nernstian response (54–59 mV/decade) for the singly charged dicyanoargentate anion over the concentration range 1×10^?2–5.8×10^?6 M. Potentiometric responses of sensors based on metal phthalocyanines and iron(II)‐bathophenanthroline are stable over the pH ranges 5–7 and 5–12, respectively. The selectivity of the sensors are fairly good over most common anions. Use of the sensors for potentiometric determination of microgram quantities of cyanide ion after conversion into dicyanoargentate anions shows an average recovery of 99.5% and a mean standard deviation of ±0.5%. Determination of cyanide ions in some exhausted electroplating bath samples gives results that compare favourably well with data obtained using the solid‐state cyanide electrode.     

A Sensitive Colorimetric Method for the Determination of Arsenic in Environmental and Biological Samples

Results of a thorough study and application of leucocrystal violet for the determination of arsenic in parts per million (ppm) levels in environmental and biological samples is described here. The proposed method is based on the reaction of arsenic with potassium iodate to liberate iodine. The liberated iodine selectively oxidises leucocrystal violet to form crystal violet dye in the presence of sodium hydroxide. The dye formed shows maximum absorbance at 592 nm. The detection limit of arsenic is 0.002 μgmL^?1 and the method obeys Beer's law over the concentration range of 0.1 μg - 1.0 μg of per 25 mL of final solution (0.004–0.04 ppm). The molar absorptivity was found to be 1.49 × 10⁶ L mol^?1 cm^?1. The proposed method was successfully applied for the determination of arsenic in various environmental and biological samples. The results are in good agreement with the standard reported method.     

Spectrophotometric Determination of Manganese with 4(5)-Imidazolealdoxime (Imalox)

Abstract

A method is described for the spectrophotometric determination of manganese by means of its complex with 4(5)-imidazolealdoxime, IMALOX, formed in alkaline medium. The colour system has its absorption maximum at 350 nm and obeys Beer's law over the range 0.8–8.0 μg of Mn per ml. The optimum range is 1–5 μg m^?1. The molar absorptivity is 7850 1 mol^?1 cm^?1. Relatively few ions interfere, and these can be masked with cyanide, tartrate and NTA. The experimental results have been critically analyzed and a comparison with the main spectrophotometric reagents for manganese is presented.     

A New Spectrophotometric Method for the Determination of Maneb in Commercial Formulations

Abstract

A new rapid, selective and sensitive method has been developed for the determination of maneb using pyrocatechol-violet(PV) as chelating reagent in the pH range of 7.5–11.0 in the presence of CTAB producing a complex which shows maximum absorption at 640 nm. Working range of the method is 0.2–3.0 μg ml^?1 maneb (manganese ethylenebisdithiocarbamate). The molar absorptivity of the color system is 79600 1 mol^?1 cm^?1 and Sandell's sensitivity is 0.0033 μg cm^?2. The reproducibility of the method has been checked by the 10 replicate analysis of 15 μg of maneb in 10 ml of solution. The method is quite sensitive and has been applied for the determination of maneb in various commercial samples, crops, grains and synthetic samples.     

A Novel Dielectric-Barrier-Discharge Loop Reactor for Cyanide Water Treatment

A novel dielectric-barrier-discharge (DBD) loop reactor was designed for the efficient degradation of cyanide anion (CN^?) in water. The circulation of cyanide water as a falling film through plasma gas discharge zone enhanced gas–liquid mass and energy transfer and induced formation of H₂O₂ which was associated with the efficient destruction of CN^?. It was observed that among different discharge gases, the CN^? degradation rate decreased in the order of Ar > air > H₂/air mixture. Depending on discharge voltage, the treatment time for complete removal of 100 ppm CN^? in this DBD loop reactor is in the range 120–300 min. The dose of Cu²⁺ catalyst in combination with in situ production of H₂O₂ enhanced the destruction of CN^? apparently in this DBD loop reactor. The treatment time for complete degradation of 100 ppm CN^? decreased from 180 min with Ar DBD discharge alone to 40 min with 40 mg/L dose of Cu²⁺ ion in water, making it an efficient means to degrade cyanide water.     

Trace Determination of Copper in Foodstuffs and Biological Samples

Abstract

A new heterocyclic bis-azo dye, 2,6-bis(4-sulfo-1-hydroxy-2-naphthylazo)pyridine, sodium salt (PBS), has been prepared and developed as a sensitive and highly selective chromogenic reagent for spectrophotometric determination of copper. The reagent is found to give a 1:2 (M/L) complex at pH 6.0. Beer's law is followed up to 1.8 ppm with an optimal concentration range between 0.2 and 1.4 ppm. Sandell's sensitivity of the color reaction was calculated to be 0.0013 µg cm^?2 with molar absorptivity of 4.9 × 10⁴ l·mol^?1 cm^?1 at 572 nm. The interfering effects of various cations and anions were also studied. The proposed method was successfully applied to the determination of copper(II) in milk, tea samples, cereals, and legume grains consumed by the Indian vegetarians and in some biological samples. Comparison of the results with those obtained using an atomic absorption spectrophotometer tested the validity of the method.