tender for purchase of chemicals , purchase of chemicals , stannous chloride dihydrate appearance: white crystalline powder; clear and colourless (4% soln. in 5n hcl). assay (titrimetric): min. 97%. impurities: sulphate (so₄) ≤ 0.02%. physical form: crystalline powder, not lumpy or discoloured. grade: pure (not technical grade). storage: 25-40°c. shelf life: 60 months. packing: glass bottle. unit:100g , chromium (iii) nitrate nonahydrate appearance: blue to violet to black shiny crystals. assay (titrimetric): min. 96%. impurities: - chloride (cl) ≤ 0.01% - sulphate (so₄) ≤ 0.05% - iron (fe) ≤ 0.05% - copper (cu) ≤ 0.005% - ammonium (nh₄) ≤ 0.01%. density: 1.80 g/ml (lit.). melting point: 60°c (lit.). grade: pure (not technical/commercial grade). storage: 25-40°c. unit:500g , copper (ii) nitrate trihydrate appearance: blue hygroscopic compound. assay (complexometric): min. 98%. impurities: - chloride (cl) ≤ 0.005% - sulphate (so₄) ≤ 0.02% - iron (fe) ≤ 0.02%. form: crystalline, not deliquesced or agglomerated. grade: pure (not extrapure/technical grade). storage: 25-40°c. imdg: un 1477, class 5.1, pg ii. unit:500g , cobalt (ii) nitrate hexahydrate appearance: red crystalline compound. assay (edta titration): min. 97%. impurities: - chloride (cl) ≤ 0.005% - sulphate (so₄) ≤ 0.03% - iron (fe) ≤ 0.01% - nickel (ni) ≤ 0.01%. grade: extrapure (not pure/technical grade). storage: 25-40°c. shelf life: 60 months. unit:250g , nickel (ii) nitrate hexahydrate appearance: green crystalline powder / deliquescent crystals; clear (10% aq. soln). assay (complexometric): min. 98%. impurities: - chloride (cl) ≤ 0.005% - sulphate (so₄) ≤ 0.05% - iron (fe) ≤ 0.02% - cobalt (co) ≤ 0.1%. grade: pure (not technical grade). imdg: un 2725, class 5.1, pg iii. storage: 25-40°c. unit:500g , magnesium nitrate hexahydrate appearance: colourless or white solid; clear and colourless (10% aq. soln). assay (edta titration): min. 98%. ph (5% aq. soln): 5.0-8.2. impurities: - insoluble matter ≤ 0.005% - chloride (cl) ≤ 0.001% - sulphate (so₄) ≤ 0.005% - iron (fe) ≤ 0.0005% - heavy metals (pb) ≤ 0.0005% - ammonium (nh₄) ≤ 0.003% - calcium (ca) ≤ 0.01% - manganese (mn) ≤ 0.0005% - sodium (na) ≤ 0.005% - potassium (k) ≤ 0.005% - barium (ba) ≤ 0.005%. grade: acs (complying with american chemical society specifications). storage: 25-40°c. unit:500g , carbon black, acetylene appearance: fine black powder, 50% compressed form - not fluffy uncompressed powder. purity (carbon content): min. 99.9%+. impurities / physical parameters: - ash content ≤ 0.3% - moisture (heating loss) ≤ 0.40% - electrical resistivity ≤ 0.30 ohm-cm - bet surface area ~90 m²/g - oil absorption number (oan): 220-260 ml/100g - mean particle size ~40 nm - ph 6-8 - iodine absorption no. ~100. grade: acetylene black (not furnace black or lamp black). application: conductive agent for electrochemical use. unit:100g , cerium (iii) nitrate hexahydrate appearance: white to pale yellow hygroscopic crystalline compound; clear in solution. assay: min. 99.9%. impurities: - chloride (cl) ≤ 0.003% - sulphate (so₄) ≤ 0.002% - iron (fe) ≤ 0.001%. grade: extrapure ar, 99.9% (not standard/pure grade at lower purity). imdg: un 1477, class 5.1, pg ii. storage: 25-40°c. unit:100g , l-ascorbic acid appearance: white crystalline powder; clear and colourless solution. assay (titrimetric): min. 99.7%. melting point (decomp.): 190-192°c. ph (5% aq. soln): 2.2-2.5. specific rotation [α]: +20.5° to +21.5° (c=10, water). impurities: - sulphate (so₄) ≤ 0.1% - oxalic acid ≤ 0.1% - iron (fe) ≤ 0.002% - copper (cu) ≤ 0.0005% - heavy metals (pb) ≤ 0.0002%. grade: extrapure annual repair (not pure/technical). storage: 25-40°c. packing: plastic bottle. unit:50g , citric acid monohydrate appearance: white crystalline compound; clear and colourless (10% aq. soln). assay (titrimetric): min. 99.5%. impurities: - sulphated ash ≤ 0.1% - sulphate (so₄) ≤ 0.015% - heavy metals (pb) ≤ 0.0005% - iron (fe) ≤ 0.0005% - oxalate ≤ 0.03%. grade: extrapure (not anhydrous citric acid; must be monohydrate form, c₆h₈o₇·h₂o, mw 210.14). storage: 25-40°c. unit:500g , urea appearance: white crystalline powder; clear and colourless (10% aq. soln). assay (calculated from n content): min. 99%. melting point: 131-135°c. impurities: - sulphated ash ≤ 0.1% - chloride (cl) ≤ 0.002% - sulphate (so₄) ≤ 0.01%. grade: extrapure (not fertiliser/commercial grade). note: must be anhydrous form (mw 60.06), not biuret-contaminated grades. storage: 25-40°c. unit:500g , uric acid appearance: white crystalline powder. assay (titrimetric): min. 99%. impurities: - sulphated ash ≤ 0.1% - water (karl fischer) ≤ 0.5%. grade: extrapure annual repair (not standard/pure grade). form: anhydrous. storage: 25-40°c. unit:10g , d-glucose anhydrous appearance: white crystalline powder; clear solution. assay (hplc, anhydrous basis): 97.5-102.0%. specific rotation [α]: +52.5° to +53.3° (c=10, water). impurities: - water (kf) ≤ 1.0% - conductivity ≤ 20 μs/cm at 25°c - maltose + isomaltose (hplc) ≤ 0.4% - maltotriose (hplc) ≤ 0.2% - fructose (hplc) ≤ 0.15% - unspecified impurities ≤ 0.10% - total related substances ≤ 0.5% - sulphated ash ≤ 0.10% - chloride (cl) ≤ 0.0125% - sulphate (so₄) ≤ 0.020%. grade: anhydrous (not monohydrate). storage: 25-40°c. unit:500g , di-potassium hydrogen phosphate anhydrous appearance: white crystalline powder. assay (by neutralization): min. 98%. ph (5% aq. soln): 8.5-9.6. loss on drying: max. 1%. impurities: - insoluble matter ≤ 0.01% - chloride (cl) ≤ 0.003% - sulphate (so₄) ≤ 0.005% - iron (fe) ≤ 0.001%. grade: acs, anhydrous (not trihydrate form; anhydrous mw 174.18 required). storage: 25-40°c. unit:500g , 4-acetamidophenol appearance: white crystalline powder or crystals. assay: min. 98%+. melting point: 168-172°c. impurities: - ph (5% soln): 5.5-6.5 - ir spectrum: conforms to authentic structure - density: 1.293 g/cm³ (21°c). grade: for synthesis, 98%+ (not pharmaceutical grade). storage: 25-40°c. note: synonyms: paracetamol, p-hydroxyacetanilide - must conform to mw 151.16. unit:100g , caffeine anhydrous appearance: white to off-white crystalline powder. assay (titrimetric): min. 98%. melting point: 234-239°c. impurities: - sulphated ash ≤ 0.1% - loss on drying ≤ 0.5% - heavy metals (pb) ≤ 0.001%. grade: pure, anhydrous (not caffeine hydrate or caffeine citrate). storage: 25-40°c. shelf life: 60 months. packing: plastic bottle. unit:100g , magnesium chloride hexahydrate appearance: colourless or white crystalline solid; clear solution (10% aq. soln). assay (complexometric): min. 99%. impurities: - water-insoluble matter ≤ 0.005% - sulphate (so₄) ≤ 0.005% - iron (fe) ≤ 0.0003% - heavy metals (pb) ≤ 0.0005% - calcium (ca) ≤ 0.01% - barium (ba) ≤ 0.003% - sodium (na) ≤ 0.01% - potassium (k) ≤ 0.01%. grade: acs (not anhydrous mgcl₂; hexahydrate form, mw 203.30 required). storage: 25-40°c. shelf life: 60 months. unit:500g , calcium chloride dihydrate appearance: white crystalline powder; clear and colourless (10% aq. soln). assay (calculated from cl): min. 99.5%. ph (5% aq. soln): 4.5-8.5. impurities: - sulphate (so₄) ≤ 0.005% - iron (fe) ≤ 0.0003% - heavy metals (pb) ≤ 0.0005% - nitrogen compounds (n) ≤ 0.002% - sodium (na) ≤ 0.01% - potassium (k) ≤ 0.01% - barium (ba) ≤ 0.003% - magnesium (mg) ≤ 0.005%. grade: extrapure ar, dihydrate (not anhydrous cacl₂; dihydrate form mw 147.02 required). storage: 25-40°c. unit:500g , ammonium chloride appearance: white crystalline powder. assay (argentometric titration): min. 99.5%. melting point (sublimation): ~340°c. impurities: - insoluble matter ≤ 0.005% - residue after ignition ≤ 0.02% - sulphate (so₄) ≤ 0.005% - iron (fe) ≤ 0.0002% - heavy metals (pb) ≤ 0.0005% - phosphate (po₄) ≤ 0.001%. grade: extrapure annual repair (not pure/technical grade). storage: 25-40°c. shelf life: 60 months. unit:500g , creatinine anhydrous appearance: white crystalline powder. assay (titrimetric, on dry basis): min. 99%. ph (5% aq. soln): 7.0-9.0. melting point: ~295°c (decomp.). impurities: - loss on drying ≤ 0.5% - sulphated ash ≤ 0.05% - chloride (cl) ≤ 0.2% - heavy metals (pb) ≤ 0.001%. grade: extrapure ar, anhydrous (not creatinine monohydrate; mw 113.12 required). storage: 25-40°c. shelf life: 60 months. unit:25g , picric acid, moistened with water appearance: pale yellow crystals moistened with approximately 30% water (for safe handling and transport). assay (on dry basis): min. 99%. water content: ~30% w/w (moistened, not dry - dry picric acid is a primary explosive). impurities: no additional inorganic or organic impurities beyond water. grade: extrapure (not dry/anhydrous form - must be water-moistened, ≥30% water). storage: 25-40°c. imdg: un no. 1344, imco class 4.1, packing group i. packing: plastic bottle. unit:500g , sarcosine appearance: white crystalline powder. assay: min. 99%. synonyms: n-methylglycine, sarcosinic acid. impurities: - sulphated ash ≤ 0.1% - heavy metals ≤ 0.001% - moisture ≤ 0.5%. grade: 99% (not 97% or technical grade). physical form: free-flowing crystalline powder (not lumpy or discoloured). storage: 25-40°c. shelf life: 60 months. note: non-hazardous substance (nonh for all transport modes). unit:100g , l-tyrosine appearance: white to off-white crystalline powder; clear (5% soln. in 2n hcl). assay (titrimetric, on dry basis): min. 99%. specific rotation [α]: -12° to -10° (c=4, n hcl). impurities: - loss on drying ≤ 0.5% - sulphated ash ≤ 0.1% - chloride (cl) ≤ 0.01% - sulphate (so₄) ≤ 0.03%. grade: extrapure chr (chromatographically pure; l-isomer only, not d,l-racemic mixture). storage: room temperature. shelf life: 60 months. packing: plastic bottle. unit:25g , sodium borohydride appearance: white crystalline hygroscopic compound. assay (iodometric): min. 98%. physical form: crystals (not powder - crystal form specified for controlled dissolution rate). impurities: - loss on drying ≤ 0.5% - mesh size (5 mesh): min. 80% retained. grade: extrapure/acs, crystal form (not powder or granule form). special handling: water-reactive; must be stored in tightly closed containers under dry, inert atmosphere. imdg: un no. 1426, imco class 4.3, packing group i. storage: 25-40°c. unit:25g , potassium ferricyanide appearance: ruby red crystalline powder; clear solution. assay (iodometric): min. 98%. ph (10% aq. soln): 6.0-9.0. density: 1.89 g/cm³. impurities: - insoluble matter ≤ 0.1% - chloride (cl) ≤ 0.05% - sulphate (so₄) ≤ 0.05% - iron (fe) ≤ 0.002% - ferrocyanide content ≤ 0.005%. grade: extrapure (not technical/photographic grade). storage: room temperature. imdg: un 3077, imco class 9, pg iii. unit:500g , potassium ferrocyanide trihydrate appearance: pale yellow crystalline powder; clear (10% aq. soln). assay (complexometric): min. 99%. impurities: - insoluble matter ≤ 0.05% - chloride (cl) ≤ 0.02% - sulphate (so₄) ≤ 0.02% - iron (fe) ≤ 0.002% - free cyanide ≤ 0.001%. grade: extrapure ar, trihydrate form (mw 422.39; not anhydrous potassium ferrocyanide). storage: room temperature. shelf life: 60 months. unit:500g , manganese (ii) nitrate tetrahydrate appearance: powder, crystals or chunks. assay (kt - karl fischer titration): min. 97.0% (purum p.a. grade). grade: purum p.a. (pro analysis), quality level 200. anion traces: - chloride (cl⁻) ≤ 50 mg/kg - sulphate (so₄²⁻) ≤ 50 mg/kg. cation traces: - ca ≤ 50 mg/kg - cd ≤ 50 mg/kg - construction of ≤ 50 mg/kg - cu ≤ 50 mg/kg - fe ≤ 50 mg/kg - k ≤ 100 mg/kg - na ≤ 100 mg/kg - ni ≤ 50 mg/kg - pb ≤ 50 mg/kg - zn ≤ 50 mg/kg. note: must be tetrahydrate form (mw 251.01), not the anhydrous or 37% liquid solution. unit:100g , choline chloride appearance: white to off-white crystalline powder; very hygroscopic. assay: min. 99%. impurities: - loss on drying ≤ 1.0% - sulphated ash ≤ 0.1% - heavy metals (pb) ≤ 0.001% - ph (5% soln): 5.0-7.0. grade: 99% (not feed-grade or 70% aqueous solution). form: solid crystalline powder (not liquid form). storage: 25-40°c. shelf life: 60 months. unit:500g , l-lactic acid pure appearance: clear, colourless to pale yellow liquid. assay (titrimetric): min. 88% (aqueous solution; not anhydrous - 88% w/w is the standard commercial form). impurities: - chloride (cl) ≤ 0.01% - sulphate (so₄) ≤ 0.01% - iron (fe) ≤ 0.001% - heavy metals (pb) ≤ 0.03%. grade: pure, l-(+) isomer (levorotatory; not d,l-racemic lactic acid). physical state: liquid. storage: 25-40°c. shelf life: 60 months. unit:500ml , peg-4000 flakes appearance: white waxy solid flakes; clear and colourless (10% aq. soln). average molecular weight: 3500-4500 (nominal peg-4000; not peg-3000 or peg-6000). melting point: 58-60°c. viscosity: ~12 cst. ph (5% aq. soln): 4.5-7.5. impurities: - water content (kf) ≤ 0.5% - sulphated ash ≤ 0.1% - heavy metals (pb) ≤ 0.001%. grade: pure, flake form (not powder or liquid peg; mw range 3500-4500 strictly). storage: 25-40°c. shelf life: 60 months. unit:500g , peg-6000 flakes appearance: white waxy solid flakes; clear and colourless (10% aq. soln). average molecular weight: 5400-6600 (nominal peg-6000; not peg-4000 or peg-8000). melting point: 60-63°c. ph (5% aq. soln): 4.5-7.5. impurities: - water content (kf) ≤ 0.5% - sulphated ash ≤ 0.1% - heavy metals (pb) ≤ 0.001% - ethylene oxide residue ≤ 1 ppm - 1,4-dioxane residue ≤ 10 ppm. grade: pure, flake form (mw range 5400-6600 strictly - distinct from peg-4000). storage: 25-40°c. unit:500g , ammonium metatungstate hydrate 99.99% trace metals basis (4n purity), total trace metals ≤150 ppm, white powder, keggin-type structure. strictly 99.99% ,not the lower-grade wo₃ or w% basis variants unit:25g , 2-methylimidazole white crystalline powder, assay ≥99% by gc, melting point 142-145°c, cas 693-98-1 strictly (not the 1-methyl or 4-methyl isomers), imdg class 8 unit:500gm , titanium (iv) bis(ammonium lactato)dihydroxide solution 50 wt.% aqueous solution, density 1.222 g/ml, refractive index 1.438, liquid form in original sealed container. unit:100ml