Chemical Sensor for Detection of Lead Levels in Herbal Medicine

A new tube type Pb2+ sensor made from two types of mixtures, namely clay-PbI2 and chitosan-PbI2 were prepared. An electromotive force (EMF) with Ag/AgCl as the reference electrode was used as the output signal. The highest performance of the Pb2+ sensor from clay-PbI2 was obtained at Pb2+ solutions in HNO3 and pH 3 with sensor sensitivity of 20.67 mV/decade. The highest performance of the Pb2+ sensor from chitosan-PbI2 was obtained at Pb2+ solutions in demineralized water with sensor sensitivity of 32.49 mV / decade. Application of the two sensors on several commercial herbal samples resulted in an average recovery of 85.62% and 94.10% for sensor from chitosan-PbI2 and clay-PbI2, respectively

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VOLTAIC CELLS IN FUSED SALTS: PART I. THE SILVER – SILVER CHLORIDE, COBALT – COBALTOUS CHLORIDE SYSTEM

Canadian Journal of Chemistry ◽

10.1139/v57-154 ◽

1957 ◽

Vol 35 (10) ◽

pp. 1139-1149 ◽

Cited By ~ 29

Author(s):

S. N. Flengas ◽

T. R. Ingraham

Keyword(s):

Electromotive Force ◽

Silver Chloride ◽

Reference Electrode ◽

Effect Of Temperature ◽

Chloride System ◽

Fused Salts ◽

Silver Silver ◽

The Right ◽

Silver Silver Chloride ◽

Voltaic Cell

A reversible silver − silver chloride reference electrode for use in melts at high temperatures has been developed. It was found that the solution of silver chloride in an equimolar mixture of KCl–NaCl melt is ideal for the range of concentrations studied, i.e. 1.0 × 10−3 to 6.0 × 10−2 mole fraction of AgCl.The electromotive force of the voltaic cell[Formula: see text]in which the half-cell to the right contains the above-mentioned reference electrode, was measured as a function of CoCl2 concentration. The applicability of the Nernst equation to this system was established. Deviation from ideality was observed in the case of the solution of CoCl2 in the melt solvent, and this was attributed to the formation of a complex. The dissociation constant of this complex was calculated as 4.50 × 10−2 at 710 °C.The effect of temperature on the electromotive force of this cell was also measured, and the heat of the cell reaction in the presence of solvent (Co + 2AgCl → CoCl2 + 2Ag) was calculated from the data as 22.8 ± 1.3 kcal.The thermodynamic significance of the standard electrode potential of the Co–Ag voltaic cell, derived experimentally as 0.324 volt, is discussed briefly.

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Herbal Medicine as a Cause of Combined Lead and Arsenic Poisoning

Human & Experimental Toxicology ◽

10.1177/096032719000900314 ◽

1990 ◽

Vol 9 (3) ◽

pp. 195-196 ◽

Cited By ~ 23

Author(s):

C.A.W. Mitchell-Heggs ◽

M. Conway ◽

J. Cassar

Keyword(s):

Herbal Medicine ◽

Reticulocyte Count ◽

Chelating Agent ◽

Arsenic Content ◽

Korean Woman ◽

Arsenic Poisoning ◽

Lead Levels ◽

Severe Difficulty ◽

High Lead ◽

Difficulty Walking

1 Combined chronic lead and arsenic poisoning was diagnosed in a 33-year-old Korean woman following consumption of a Korean herbal medicine prescribed for haemorrhoids. 2 The patient had malaise, severe difficulty walking, arthralgia, oedema and abdominal pain with diarrhoea. 3 Investigation showed anaemia with basophilic stippling, fragmentation and a raised reticulocyte count. 4 Raised blood and urine lead levels and urine arsenic levels were found. 5 Analysis of the herbal medicine revealed a high lead and arsenic content. 6 Treatment with the newer chelating agent 2,3-dimercaptosuccinic acid was successful, with no detectable side-effects.

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Image Reversal Resist Photolithography of Silicon-Based Platinum and Silver Microelectrode Pattern

Sains Malaysiana ◽

10.17576/jsm-2021-5002-22 ◽

2021 ◽

Vol 50 (2) ◽

pp. 515-523

Author(s):

Nurulhaidah Daud ◽

Nor Farhah Razak ◽

Normahirah Nek Abd Rahman ◽

Azizah Mohd Zahidi ◽

Siew Xian Chin ◽

...

Keyword(s):

Chemical Sensor ◽

Reference Electrode ◽

Side Wall ◽

Percentage Yield ◽

Wet Chemical ◽

Lift Off ◽

Image Reversal ◽

Silicon Based ◽

Arsenic Determination ◽

High Chemical Stability

Silicon-based platinum (Pt) and silver (Ag) microelectrodes are constructed using photolithography technique and used in detecting arsenic activity in different electrolytes. Pt and Ag have good properties either as a working, a counter, or a reference electrode due to their low electrical resistance, high melting point, and high chemical stability. This chemical sensor has the ability to detect the changes in the level or activity of arsenic in electrolytes. Patterning these metals by wet chemical or dry etching is not a feasible process as these metals cannot be etched properly. The lift-off process can be applied to ease the etching process, but it has a major problem whereby the metal particles or ears may remain at the edges at the end of the process. The process variables, particularly the resist slope, were investigated to reduce possible defects using an image reversal resist. The thickness and angle of the resist side wall were measured by SEM. The effects of many factors that may influence or resist steep angle formation were analyzed and optimized with the Design of Experiment (DOE) technique to achieve the target recipe of resist angle < 60°. The lower angle of the resist side wall resulted in a better percentage yield of good electrode pattern after the lift-off process. The ability of fabricated microelectrode and influence of supporting electrolytes in arsenic determination were discussed.

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Electrochemical studies of lanthanum and lanthanum–zinc alloys in fused LiCl–KCl eutectic

Canadian Journal of Chemistry ◽

10.1139/v69-561 ◽

1969 ◽

Vol 47 (18) ◽

pp. 3387-3391 ◽

Cited By ~ 16

Author(s):

Jean-Baptiste P. F. Lesourd ◽

James A. Plambeck

Keyword(s):

Intermetallic Compound ◽

Liquid Alloy ◽

Electromotive Force ◽

Reference Electrode ◽

Electrochemical Studies ◽

Saturated Liquid ◽

Kcal Mole ◽

Standard Potential ◽

Zinc Alloys ◽

Electrochemical Separation

The electromotive force of cells of the type La(s)/LiCl–KCl (eutectic) + LaCl3/(La + Zn, saturated liquid alloy) has been measured over the temperature range 450–600 °C. Thermodynamic functions for the limiting lanthanum–zinc solid intermetallic compound existing in this range are: ΔGf0, −58.8 kcal/mole, ΔSf0, −53 cal/deg mole, and ΔHf0, −97 kcal/mole at 450 °C. The standard potential (mole fraction scale) of the La(III)/La(0) electrode is −2.883 V with respect to the Pt(II)/Pt reference electrode at 450 °C. The significance of these measurements for the electrochemical separation of lanthanum and uranium is discussed.

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STUDY OF A FREQUENCY OUTPUT TEMPERATURE SENSOR BASED ON A QUANTUM HETEROSTRUCTURE WITH A NEGATIVE DIFFERENTIAL RESISTANCE

HERALD of Khmelnytskyi national university ◽

10.31891/2307-5732-2021-295-2-156-164 ◽

2021 ◽

Vol 295 (2) ◽

pp. 156-164

Author(s):

A. OSADCHUK ◽

◽

V. OSADCHUK ◽

O. OSADCHUK ◽

◽

...

Keyword(s):

Equivalent Circuit ◽

Temperature Sensor ◽

Output Signal ◽

Negative Differential Resistance ◽

Differential Resistance ◽

Temperature Sensors ◽

Conversion Function ◽

Operating Modes ◽

Sensor Sensitivity ◽

Frequency Output

Physical processes in a quantum two-barrier heterostructure, which is the basis for the development of tunnel-resonant diodes, are considered. These studies have shown that tunnel resonance diodes can be used as temperature sensors with a frequency output signal. The use of devices with negative differential resistance makes it possible to significantly simplify the design of temperature sensors in the entire radio frequency range, at which, depending on the operating modes of the sensor, an output signal can be obtained both in the form of harmonic oscillations and in the form of impulse oscillations of a special form. The study of the characteristics of the sensor is based on the equivalent circuit of the tunnel-resonant diode, which takes into account its capacitive and inductive properties. The current-voltage characteristic of the sensor has a falling section, which is responsible for the appearance of a negative differential resistance in this section. The descending section arises due to a decrease in the current that flows through the double-barrier quantum heterostructure, with an increase in voltage. A decrease in the current occurs due to a decrease in the transparency coefficient of the potential barriers of the heterostructure. A mathematical model of the temperature sensor has been developed, on the basis of which the analytical dependences of the change in the elements of the equivalent circuit of the sensor on temperature, as well as the transformation function and sensitivity, have been determined. It is shown that the main contribution to changes in the conversion function and sensor sensitivity is made by the change in the negative differential resistance with a change in temperature. This, in turn, results in different readings of the instrument’s output frequency. The sensor sensitivity was varied from 480 kHz/0С to 220 kHz/0С in the temperature range from -150 0С to 50 0С.

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Pengembangan Sensor Kimia Berbasis Strip Tes untuk Deteksi Logam Berat Merkuri pada Sampel Produk Jamu

Pustaka Kesehatan ◽

10.19184/pk.v9i1.16552 ◽

2021 ◽

Vol 9 (1) ◽

pp. 25

Author(s):

Rizqi Amaliyah ◽

Nia Kristiningrum ◽

Indah Purnama Sary

Keyword(s):

Heavy Metal ◽

Herbal Medicine ◽

Chemical Sensor ◽

Medicinal Preparation ◽

The Body ◽

Mercury Contamination ◽

P Value ◽

Test Strips ◽

Significant Difference ◽

Strip Test

The use of plants as a traditional medicine in the modern era is still in high demand. One of the herbs commonly used by Indonesian is analgesic herbal medicine. The safety aspect of herbal medicine should be considered, such as heavy metal contamination. Mercury is the typical heavy metal found in polluting herbal plants. The maximum mercury level allowed in a medicinal preparation has been regulated by BPOM RI, as much as ≤ 0.5 ppm. A high level of mercury contamination causing toxic effects on the body due to protein precipitation, which inhibits enzyme activity and acts as a corrosive material. A technology that allows the detection of mercury is a chemical sensor. The strip test is optimal if the reagent 1-(2-thiazolyl azo)-2-naphthol (TAN) concentration at 1000 ppm and the sample has been confirmed at pH 7. The results of the strip test characterization showed that the response time was in the range of minutes 17 to 24, the use time of the test strips for 28 days if stored in room temperature and 29 days if stored at in refrigerator temperature, linearity with r = 0.998, Vx0 = 3.96%, p-value = 0.00000172, LOD = 0.102 ppm and LOQ = 0.306 ppm, interference value <5%, precision with RSD 6.54%, and accuracy with the value of % recovery 98.007%. T-test analysis showed p= 0.872, meaning no significant difference between the application of TAN-based test strips with the ICP-AES method.

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Thermodynamic Investigation of the Reaction: by Electromotive Force Measurements

Canadian Journal of Chemistry ◽

10.1139/v71-251 ◽

1971 ◽

Vol 49 (9) ◽

pp. 1545-1549 ◽

Cited By ~ 7

Author(s):

A. W. Espelund ◽

S. N. Flengas

Keyword(s):

Free Energy ◽

Thermodynamic Properties ◽

Electromotive Force ◽

Electrochemical Method ◽

Standard Free Energy ◽

Reference Electrode ◽

Standard Free Energy Change ◽

Force Measurements ◽

Thermodynamic Investigation ◽

Electromotive Force Measurements

The thermodynamic properties of the system CoO–CoSO4 have been investigated over the temperature range 560 to 916 °C, by an electrochemical method using a ZrO2–CaO solid electrolyte and an oxygen reference electrode. The standard free energy change for the reaction[Formula: see text]can be expressed by[Formula: see text]and is given with an accuracy of ± 400 cal.

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