Browsing by Author "Singh, Raksha"

Now showing 1 - 5 of 5
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    A low cost yet highly sensitive silver nanoprobe for naked eye detection and determination of bisulphate (HSO4-) in a few real samples
    (Elsevier B.V., 2022) Singh, Raksha; Yadav, Minu; Kumar Singh, Anurag; Mishra, S.K.; Upadhyay, K.K.
    Herein, we report a simple and economical yet highly sensitive and efficient silver nanoresonators based protocol for naked eye detection of a janus-faced ion like bisulphate from its two real samples in real time. The SEM-TEM, DLS, AFM and EDAX alongwith spectroscopic studies have further substantiated our observation in the same context. The quantification of bisulphate in one of its real sample through UV�Vis spectroscopy using these nanoprobes as indicator has also been carried out successfully. The Raman measurements have clearly indicated the rich SERS potential of these silver nanoresonators. � 2022 Elsevier B.V.
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    A rapid and sensitive colorimetric discrimination and detection of cysteine, homocysteine and glutathione by phloroglucinol-functionalized silver nanoresonators with real applications
    (Royal Society of Chemistry, 2023) Singh, Anurag Kumar; Singh, Raksha; Yadav, Minu; Sharma, Manish; Tiwari, Ida; Upadhyay, K.K.
    This study describes the preparation and application of simple yet effective silver nanoprobes for the facile colorimetric discrimination and detection of cysteine, homocysteine and glutathione in real time at the micro molar levels with three distinct colors. These nanoprobes were further exploited to detect and determine cysteine and glutathione from their respective commercial samples, with recoveries exceeding 80%. FT-IR spectroscopy, UV-Vis spectroscopy, SEM, TEM, EDAX, AFM and DLS studies have supported our findings. � 2023 The Royal Society of Chemistry.
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    Colorimetric and SERS detection of H2S by D (�) galactose functionalized truncated hexagonal bipyramidal silver nanoresonators
    (Elsevier B.V., 2023) Yadav, Minu; Singh, Raksha; Singh, Anurag Kumar; Sharma, Manish; Tiwari, Ida; Upadhyay, Kaushal Kumar
    We report hereby, a simple and easy to perform experimental protocol for highly selective and real time dual mode (Colorimetric and SERS) detection of hydrogen sulfide (H2S) in aqueous medium through galactose activated silver nanoresonators. The truncated hexagonal bipyramids were clearly seen in TEM images of as prepared silver nanoparticles. The interaction of H2S with these AgNPs induced their etching followed by agglomeration and led optical (greenish yellow to brown) as well as SERS changes. The optical changes were further exploited to determine the H2S from its two spiked samples of human saliva and blood serum each with their percent recovery rates of 91, 82 and 67, 72 respectively. These determinations were totally free from any visual interference from any biothiols like cysteine, homocysteine and glutathione. The optimized silver nanosensor exhibited an excellent linear response in the concentration range of 50�130 nM along with its limit of detection (LOD) as 2.83 nM. Moreover, consecutive additions of different aliquots of H2S to a fixed volume of these silver colloids exhibited stepwise decrease in intensity of their absorption bands in the Raman silent (10�500 cm?1) and Raman finger print regions (500�1800 cm?1) upon their excitation at 532 nm. Our findings are well supported by spectroscopic (FTIR, UV�Vis and Raman) and microscopic (SEM, TEM, DLS and zeta potential). � 2023 Elsevier B.V.
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    Naked-eye detection of cysteine/homocysteine through silver nano-resonators and specific identification of homocysteine through nanoresonator-thiosulphate conjugate
    (Royal Society of Chemistry, 2022) Singh, Raksha; Singh, Anurag Kumar; Yadav, Minu; Sharma, Manish; Tiwari, Ida; Upadhyay, K.K.
    This study presents simultaneous colorimetric detection of two very similar amino thiols viz. cysteine and homocysteine at their micro and sub-micromolar levels, respectively, through the aggregation of citrate capped silver nanoparticles. A rare kind of categorical naked-eye detection of homocysteine over cysteine was accomplished through the conjugation of these AgNPs with thiosulphate. The UV-Vis and SERS characteristics of these AgNPs were also more prominent with homocysteine compared to cysteine. The quantification of cysteine was performed in a pharmaceutic sample with an accuracy of 89 � 5%. � 2022 The Royal Society of Chemistry.
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    Salicylazine activated plasmonic silver nanoprisms for identification of Fe(ii) and Fe(iii) from aqueous solutions
    (Royal Society of Chemistry, 2021) Singh, Deovrat; Singh, Raksha; Kumar, Abhay; Singh, Anurag Kumar; Yadav, Minu; Upadhyay, K.K.
    Herein, we report the synthesis and characterization, along with the successful application, of silver nanoprisms for the identification of Fe(ii)/Fe(iii) at the nanomolar level. A few real samples have also been analyzed successfully. The scanning electron microscopy (SEM)-transmission electron microscopy (TEM) imaging of the sensing events indicate analyte induced changes in the morphology and geometrical pattern of the silver nanoparticles. � The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2021.