Chemistryhttp://starc.stthomas.ac.in:8080/xmlui/xmlui/handle/123456789/52026-04-29T14:34:44Z2026-04-29T14:34:44ZInvestigations on silver incorporated RF sputtered ZnO thin filmsFrancis, MeldaKuruvilla, AnuFrancis, Martin PLakshmi, Mhttp://starc.stthomas.ac.in:8080/xmlui/xmlui/handle/123456789/4422025-02-11T10:05:04Z2020-06-27T00:00:00ZInvestigations on silver incorporated RF sputtered ZnO thin films
Francis, Melda; Kuruvilla, Anu; Francis, Martin P; Lakshmi, M
: In this work, ZnO thin films were fabricated using RF Magnetron Sputtering technique on
ITO substrates. The operating parameters time of deposition, Argon working pressure, distance
between target and substrate, oxygen pressure, RF power etc. were optimized so as to get good quality
ZnO thin films. The prepared films were characterised using various techniques like XPS, SEM, EDS
etc. It was observed that the sheet resistance of the pristine ZnO film was around 200 MΩcm-1
even
when coated on ITO substrates. For device level application the resistance of the film must be low.
Therefore silver was incorporated by sputtering, and it served the purpose of reducing the sheet
resistance of pristine ZnO film. The Ag incorporated films were also characterised by the above
mentioned techniques. Detailed compositional analysis was done using depth profiling method of XPS.
Resistance measurements were also done in these samples. The sheet resistance decreased (from ~ 200
MΩcm-1
) to a range of about 500 Ωcm-1 by silver incorporation.
2020-06-27T00:00:00ZCrystallization of zinc azole complex incorporated Strandberg-type cluster-based solids: Synthesis, structure and photoluminescence studiesRadhakrishnan, Raji ChorenjethJoseph, JishaJadon, ManishaKuriakose, MemsyThomas, Jencyhttp://starc.stthomas.ac.in:8080/xmlui/xmlui/handle/123456789/4302025-01-30T10:33:20Z2024-04-01T00:00:00ZCrystallization of zinc azole complex incorporated Strandberg-type cluster-based solids: Synthesis, structure and photoluminescence studies
Radhakrishnan, Raji Chorenjeth; Joseph, Jisha; Jadon, Manisha; Kuriakose, Memsy; Thomas, Jency
Two new zinc azole complexes incorporated Strandberg-type cluster-based solids, namely
(Hpz)6{Zn(pz)4(H2O)2}[{Zn(pz)2P2Mo5O23}2]8H2O (1) and (Himi)4{Zn(imi)3P2Mo5O23}7H2O (2) were
crystallized using isomeric azole ligands, i.e., pyrazole (pz) and imidazole (imi), respectively. While solid 1
crystallized in triclinic system with space group P-1 with cell parameters a = 9.5647(15), b = 12.558(2), c =
20.340(3) A˚ , a = 75.907(7), b = 84.727(6), c = 87.525(7), Z = 1; 2 crystallized in orthorhombic system with
space group P212121 having cell parameters a = 12.048(3), b = 19.561(5), c = 20.732(5) A˚ , Z = 4. Both
pyrazole and imidazole can form a complex with zinc centres to form an extended solid in 1 and a derivatized
Strandberg-type cluster in 2. Interestingly, 1 is a new supramolecular isomer of previously reported solid viz.,
(pz)[{Zn(pz)3}3{P2Mo5O23}]2H2O and 2 is the only example wherein a zinc imidazole complex has
derivatized a Strandberg-type cluster. Detailed structure analysis of 1 and 2 was carried out, and the role of
tectons in dictating the self-assembly of these solids was evaluated. In addition, a solid-state photoluminescence study was carried out for 1 and 2 at room temperature.
2024-04-01T00:00:00ZDevelopment and validation of a GC-MS method for analysis of Dithiocarbamate Fungicide residues in the Spices Cardamom (Elettaria cardamomom) and black pepper (Piper nigrum)Natarajan, Ramesh BabuKakkasery, Joby ThomasArimboor, RanjithJacob, JobyThankan, Binumolhttp://starc.stthomas.ac.in:8080/xmlui/xmlui/handle/123456789/4242025-01-29T09:54:05Z2022-05-13T00:00:00ZDevelopment and validation of a GC-MS method for analysis of Dithiocarbamate Fungicide residues in the Spices Cardamom (Elettaria cardamomom) and black pepper (Piper nigrum)
Natarajan, Ramesh Babu; Kakkasery, Joby Thomas; Arimboor, Ranjith; Jacob, Joby; Thankan, Binumol
Dithiocarbamates constitute an important class
of broad-spectrum antifungal compounds used extensively
in agriculture, including in the cultivation of spices. Maximum residue limits for these compounds have been
enforced by several importing countries in international
food trade. Validation of analytical methods for dithiocarbamates in spices have not been reported previously. A
quick and sensitive method for estimation of total dithiocarbamates as carbon disulphide (CS2) using GC-MS in
two major spices, viz. small cardamom (Elettaria cardamomom) and black pepper (Piper nigrum) was optimized
and validated. Dithiocarbamate residues in these spice
matrices were extracted and subjected to acid hydrolysis
followed by reduction to CS2, which was then quantitatively absorbed into isooctane and analysed using GC-MS,
employing selected ion monitoring and post-run mid-column backflush technique. For fortification levels from 0.1
to 1.0 mg kg- 1
, recoveries obtained ranged from 75 to
98% in cardamom and 76–98% in black pepper, with intraday precision (RSDr) \12% and inter-day precision
(RSDR) \15% in all cases. Limit of Quantification of
0.05 mg kg- 1 was achieved in both spices. It was found
that there was negligible interference in quantitative
accuracy due to essential oils present in the two spices
studied. Matrix effect was seen to be suppressive in the two
spices studied, and sufficiently low to exclude the use of
matrix-matched calibration in routine quantitative analysis.
The optimized analytical method was found to be suitable for evaluation of compliance of real samples against
the Codex maximum residue limits for cardamom and
black pepper. Safety evaluation for human consumption,
based on the incidence of Dithiocarbamate residues, was
performed in real samples of cardamom and black pepper.
This method offers the possibility of extending applicability to other spices also.
2022-05-13T00:00:00ZChitosan – hydrogen iodide salt supported graphite electrode: A simple and novel electrode for the reduction of nitro group under electrochemical conditionDeena, P. L.Selvaraj, Savariraj JosephThomas, K. Jobyhttp://starc.stthomas.ac.in:8080/xmlui/xmlui/handle/123456789/4202025-01-28T06:13:30Z2023-11-01T00:00:00ZChitosan – hydrogen iodide salt supported graphite electrode: A simple and novel electrode for the reduction of nitro group under electrochemical condition
Deena, P. L.; Selvaraj, Savariraj Joseph; Thomas, K. Joby
The present investigation provides a unique, simple, selective and efficient method for the electrochemical reduction of aromatic nitro groups into amines using chitosan-hydrogen iodide salt supported graphite electrode. 3:1 tetrabutyl ammonium chloride and acetic acid mixture was used as the medium for electrolytic process and a constant voltage of 5 V applied between the modified electrodes. The reaction was found to be selective and further reduction of amines was not observed. The purity of the products was checked with HPLC and characterized using spectroscopic tools. The electrochemical synthesis resulted in moderate to good yields of amino compounds which were higher than the reduction using conventional graphite electrodes. Quaternary ammonium chloride behaved as supporting electrolyte during synthesis and the reaction did not progress in the absence of acetic acid. The redox characteristic of the process was studied by cyclic voltammetry of the reaction mixture.
2023-11-01T00:00:00Z