Determination of Water Content of Nitrogen Containing Hydrogen Sulfide by Karl Fischer Coulometric Titration

Zhi, Xu; Wang, Haifeng; Liu, Baijun; Song, Xiaoping; Li, Zhanyuan; Li, Jia

doi:10.2116/analsci.18p575

Cited by 9 publications

(2 citation statements)

References 15 publications

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“…For example, the residual moisture content is the most important factor affecting the quality and stability of freeze-dried reagents [18,19], and the commonly applied reduced weight method is inadequate. Karl-Fischer (KF) titration is an absolute method for measuring residual moisture content and is accepted as the standard method for water content determination in freeze-dried reagents [20], but is rarely applied in studies because of its complexity.…”

Section: Introductionmentioning

confidence: 99%

Room-temperature-storable PCR mixes for SARS-CoV-2 detection

Wang

Zhong

et al. 2020

Clinical Biochemistry

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A novel coronavirus (severe acute respiratory syndrome coronavirus 2, SARS-CoV-2) emerged in late 2019, causing an outbreak of pneumonia [coronavirus disease 2019 (COVID-19)] globally. Although the use of ready-made reaction mixes can enable more rapid PCR-based diagnosis of COVID-19, the need to transport and store these mixes at low temperatures presents challenges to already overburdened logistics networks. Methods: Here, we present an optimized freeze-drying procedure that allows SARS-CoV-2 PCR mixes to be transported and stored at ambient temperatures, without loss of activity. Additive-supplemented PCR mixes were freeze-dried. The residual moisture of the freeze-dried PCR mixes was measured by Karl-Fischer titration. Results: We found that the freeze-dried PCR mixes with~1.2% residual moisture are optimal for storage, transport, and reconstitution. The sensitivity, specificity, and repeatability of the freeze-dried reagents were similar to those of freshly prepared, wet reagents. The freeze-dried mixes retained activity at room temperature (18~25°C) for 28 days, and for 14 and 10 days when stored at 37°C and 56°C, respectively. Conclusion: The uptake of this approach will ease logistical challenges faced by transport networks and make more cold storage space available at diagnosis and hospital laboratories.

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Section: Introductionmentioning

confidence: 99%

Room-temperature-storable PCR mixes for SARS-CoV-2 detection

Wang

Zhong

et al. 2020

Clinical Biochemistry

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“…2 Zhi et al applied the Karl Fischer coulometric titration method to determine the water content of nitrogen-containing hydrogen sulfide. 3 Anderson et al utilized a potentiometric titration curve to calculate the concentration of polyquaternium polymers which are used for medical studies, wastewater treatment, and environmental contaminant remediation. 4 Routine tests of the chemical oxygen demand (COD) is mostly achieved by batchwise titration, but in recent years several alternative methods have been reported.…”

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confidence: 99%