scholarly journals Lead Assays with Smartphone Detection Using a Monolithic Rod with 4-(2-Pyridylazo) Resorcinol

Molecules ◽  
2021 ◽  
Vol 26 (18) ◽  
pp. 5720
Author(s):  
Piyanat Issarangkura Na Ayutthaya ◽  
Chonnipa Yeerum ◽  
Kullapon Kesonkan ◽  
Kanokwan Kiwfo ◽  
Kate Grudpan ◽  
...  
Keyword(s):  
Chemical Sensor ◽  
Glass Tube ◽  
B Value ◽  
Limit Of Quantitation ◽  
Simple Chemical ◽  
Site Water ◽  
Standard Calibration ◽  
Single Standard ◽  
Standard Sample Solution ◽  
Drinking Water Samples

A monolithic rod of polyurethane foam–[4-(2-pyridylazo) resorcinol] (PUF–PAR) as a simple chemical sensor for lead assays with smartphone detection and image processing was developed. With readily available simple apparatus such as a plastic cup and a stirrer rod, the monolithic PUF rod was synthesized in a glass tube. The monolithic PUF–PAR rod could be directly loaded by standard/sample solution without sample preparation. A one-shot image in G/B value from a profile plot in ImageJ for a sample with triplicate results via a single standard calibration approach was obtained. A linear single standard calibration was: [G/B value] = −0.038[µg Pb2+] + 2.827, R2 = 0.95 for 10–30 µg Pb2+ with a limit of quantitation (LOQ) of 33 µg L−1. The precision was lower than 15% RSD. The proposed method was tested by an assay for Pb2+ contents in drinking water samples from Bangkok. The results obtained by the proposed method agree with those of ICP-OES and with 100–120% recovery, demonstrating that the method is useful for screening on-site water monitoring.

scholarly journals Preparative Method for Isolating α-Zearalenol and Zearalenone Using Extracting Disk

1999 ◽  
Vol 82 (1) ◽  
pp. 90-94 ◽  
Author(s):  
George M Ware ◽  
Yuhong Zhao ◽  
Shia S Kuan ◽  
Allen S Carman
Keyword(s):  
Limit Of Detection ◽  
Solid Phase ◽  
Control Sample ◽  
Preparative Method ◽  
Reversed Phase ◽  
Fluorescence Detector ◽  
Coefficients Of Variation ◽  
Limit Of Quantitation ◽  
Standard Calibration ◽  
Liquid Chromatographic

Abstract A liquid chromatographic method is described for the determination of zearalenol and zearalenone in corn. Zearalenol and zearalenone are extracted from corn with methanol–water (1+1) and cleaned up using a solid-phase extraction (SPE) disk, separatedon a reversed-phase analytical column, and detected with a fluorescence detector. The SPE disk concentrated and cleanly separated zearalenol and zearalenone from sample interferences. Standard calibration curves for zearalenol and zearalenone for the concentration range 25–500 ng/mL were linear. The small extract disk had a column capacity equivalent to 1 g extracted corn. Zearalenol and zearalenone were added at levels ranging from 10 to 2000 ng/g to a control sample that contained no detectable levels of zearalenol and zearalenone. Both toxins were recovered from spiked samples at 106.3 and 103.8%, with coefficients of variation of 7.6 and 13.0%, respectively. The method has an estimated reliable limit of detection and limit of quantitation around 10 and 40 ng/g for each toxin, respectively.

A single standard calibration module for flow analysis systems based on solenoid microdevices

Talanta ◽  
2009 ◽  
Vol 79 (2) ◽  
pp. 205-210 ◽  
Author(s):  
Łukasz Tymecki ◽  
Kamil Strzelak ◽  
Robert Koncki
Keyword(s):  
Flow Analysis ◽  
Standard Calibration ◽  
Single Standard

Novel single standard calibration and dilution method performed by the sequential injection technique

The Analyst ◽  
1992 ◽  
Vol 117 (12) ◽  
pp. 1839-1844 ◽  
Author(s):  
Alan Baron ◽  
Miguel Guzman ◽  
Jaromir Růžička ◽  
Gary D. Christian
Keyword(s):  
Injection Technique ◽  
Dilution Method ◽  
Sequential Injection ◽  
Standard Calibration ◽  
Single Standard

scholarly journals Iodine determination in mineral water using ICP-MS: method development and analysis of brands available in Israeli stores

2021 ◽  
Author(s):  
Vasiliy Rosen ◽  
Orit Gal Garber ◽  
Yona Chen
Keyword(s):  
Drinking Water ◽  
Water Samples ◽  
Mineral Water ◽  
Method Development ◽  
Molar Ratio ◽  
Icp Ms ◽  
Limit Of Quantitation ◽  
Drinking Water Samples ◽  
Bottled Mineral Water ◽  
Iodine Determination

Reliable iodine determination in drinking water samples has gained importance in the last few decades, mostly due to intensive use of both desalinized water that lacks several important nutritional elements, and bottled mineral water. ICP-MS is a sensitive, high-throughput method for iodine determination that must be performed under alkaline conditions because of the volatile nature of some iodine species. However, in water samples with high pH (>10), slow precipitation of calcium (Ca) and/or magnesium (Mg) carbonates leads to clogging of the ICP-MS nebulizer. We propose preventing this precipitation by adding the chelating agent ethylenediaminetetraacetic acid (EDTA) at 0.1% to a 2% ammonium hydroxide matrix. This concentration of EDTA sufficed for most drinking water samples studied, as long as a 1:1 molar ratio of EDTA to Ca+Mg concentration in the water was maintained. The limit of quantitation of the developed method for iodine was <0.1 µg L-1. The average iodine concentration in various brands of bottled mineral water sold in Israel was relatively low (7.67 ± 6.38 µg I L-1). Regular consumption of either desalinated water or bottled mineral water may induce iodine deficiency in Israeli consumers. Therefore, continuous follow-up of the iodine status in both tap and bottled water is strongly recommended.

scholarly journals Single standard calibration and data processing in flow injection titration based on concentration gradients

1997 ◽  
Vol 19 (5) ◽  
pp. 157-164 ◽  
Author(s):  
M. C. U. Araújo ◽  
A. V. Santos ◽  
R. S. Honorato ◽  
C. Pasquini
Keyword(s):  
Flow Injection ◽  
Stoichiometric Ratio ◽  
Concentration Gradients ◽  
Average Accuracy ◽  
Mixing Chamber ◽  
Relative Standard ◽  
Standard Calibration ◽  
Conductimetric Detection ◽  
Single Standard

This paper describes use of gradients of concentration generated in flow injection (FI) systems to perform determinations based on points where the concentration of titrant and analyte are at stoichiometric ratio. Two procedures were developed. In one procedure the titrant is injected in a FI manifold and merges with the sample which is continuously pumped towards the detector. In the other procedure the sample is injected and merged with the titrant which is continuously pumped. Both techniques make use of concentration gradients of the sample or titrant generated in FI manifolds that contain a mixing chamber. This gradient is calibrated employing only one standard solution (usually the titrant) in order to convert any detector signal, obtained in the elapsed time after injection, to instantaneous concentration values. The flow system is microcomputer controlled and data are treated to locate points where the concentration of titrant and analyte are at the stoichiometric ratio. These points are found in abrupt changes of the signal × concentration curves obtained in the presence of the reaction. The method has been evaluated for determination of Fe(II) and acetic acid by spectrophotometric and conductimetric detection, respectively. Results show a mean relative standard deviation lower than 1%, an average accuracy of 1% and a high sampling processing capability (40 to 60 samples per hour).

scholarly journals Development and Validation of an LC-MS/MS Assay to Quantitate 2′,4′,6′-Trihydroxyacetophenone in Rat and Dog Plasma and its Application to a Pharmacokinetic Study

Molecules ◽  
2020 ◽  
Vol 25 (19) ◽  
pp. 4373
Author(s):  
Hee Jo Yoo ◽  
Se-Jung Hwang ◽  
Jeong-Hun Lee ◽  
Wang-Seob Shim ◽  
Yun-Woong Choi ◽  
...  
Keyword(s):  
Pharmacokinetic Study ◽  
Ammonium Acetate ◽  
Multiple Reaction Monitoring ◽  
Internal Standard ◽  
Dog Plasma ◽  
Limit Of Quantitation ◽  
Regulatory Guidelines ◽  
One Step ◽  
Standard Calibration ◽  
Development And Validation

In the present study, a simple, rapid, and reliable bioanalytical method was developed using liquid chromatography with tandem-mass spectrometry (LC-MS/MS) to quantify 2′,4′,6′-trihydroxyacetophenone (THAP) in rat and dog plasma with 2′,4′,6′-trihydroxybenzaldehyde as an internal standard (IS). The LC-MS/MS instrument was operated in the multiple reaction monitoring (MRM) mode to detect THAP at m/z transition 166.89 > 82.8 and IS at 152.89 > 82.8, respectively. A simple, one-step protein precipitation (PP) method was employed with acetonitrile for sample preparation. Utilizing a Gemini C18 column, THAP and IS were separated with an isocratic mobile phase consisting of 10 mM ammonium acetate and methanol (10:90, v/v) at a flow rate of 0.2 mL/min. Total chromatographic run time was 2.5 min per sample injection. The standard calibration curve for THAP was linear (r2 ≥ 0.9987) over the concentration range of 0.1 to 100 µg/mL with the lower limit of quantitation (LLOQ) of 0.1 µg/mL (S/N ratio > 10). According to the regulatory guidelines from the U.S. Food and Drug Administration (FDA) and the Korea Ministry of Food and Drug Safety (MFDS), our newly developed biomedical analytical method was fully and adequately validated in terms of selectivity, sensitivity, linearity, intra- and inter-day precision and accuracy, recovery, matrix effect, stability, and dilution integrity. Our validated assay was successfully utilized in a nonclinical pharmacokinetic study of THAP in rats and dogs.

scholarly journals Iodine determination in mineral water using ICP-MS: method development and analysis of brands available in Israeli stores

2021 ◽  
Author(s):  
Vasiliy Rosen ◽  
Orit Gal Garber ◽  
Yona Chen
Keyword(s):  
Drinking Water ◽  
Water Samples ◽  
Mineral Water ◽  
Method Development ◽  
Molar Ratio ◽  
Icp Ms ◽  
Limit Of Quantitation ◽  
Drinking Water Samples ◽  
Bottled Mineral Water ◽  
Iodine Determination

Reliable iodine determination in drinking water samples has gained importance in the last few decades, mostly due to intensive use of both desalinized water that lacks several important nutritional elements, and bottled mineral water. ICP-MS is a sensitive, high-throughput method for iodine determination that must be performed under alkaline conditions because of the volatile nature of some iodine species. However, in water samples with high pH (>10), slow precipitation of calcium (Ca) and/or magnesium (Mg) carbonates leads to clogging of the ICP-MS nebulizer. We propose preventing this precipitation by adding the chelating agent ethylenediaminetetraacetic acid (EDTA) at 0.1% to a 2% ammonium hydroxide matrix. This concentration of EDTA sufficed for most drinking water samples studied, as long as a 1:1 molar ratio of EDTA to Ca+Mg concentration in the water was maintained. The limit of quantitation of the developed method for iodine was <0.1 µg L-1. The average iodine concentration in various brands of bottled mineral water sold in Israel was relatively low (7.67 ± 6.38 µg I L-1). Regular consumption of either desalinated water or bottled mineral water may induce iodine deficiency in Israeli consumers. Therefore, continuous follow-up of the iodine status in both tap and bottled water is strongly recommended.

scholarly journals Determination of Albumin, Glucose, and Creatinine Employing a Single Sequential Injection Lab-at-Valve with Mono-Segmented Flow System Enabling In-Line Dilution, In-Line Single-Standard Calibration, and In-Line Standard Addition

Molecules ◽  
2020 ◽  
Vol 25 (7) ◽  
pp. 1666 ◽  
Author(s):  
Kanokwan Kiwfo ◽  
Wasin Wongwilai ◽  
Tadao Sakai ◽  
Norio Teshima ◽  
Kate Grudpan
Keyword(s):  
Enzymatic Reaction ◽  
Standard Addition ◽  
Cost Effective ◽  
Sequential Injection ◽  
Slow Reaction ◽  
Preparation Step ◽  
Standard Calibration ◽  
Single Standard ◽  
Line Standard

A mono-segmented sequential injection lab-at-valve (SI-LAV) system for the determination of albumin, glucose, and creatinine, three key biomarkers in diabetes screening and diagnosis, was developed as a single system for multi-analyte analysis. The mono-segmentation technique was employed for in-line dilution, in-line single-standard calibration, and in-line standard addition. This made adjustments to the sample preparation step easy unlike the batch-wise method. The results showed that the system could be used for both fast reaction (albumin) and slow reaction (glucose with enzymatic reaction and creatinine). In the case of slow reaction, the analysis time could be shortened by using the reaction rate obtained with the SI-LAV system. This proposed system is for cost-effective and downscaling analysis, which would be applicable for small hospitals and clinics in remote places with a small number of samples but relatively fast screening would be needed.

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