Tender For supply of standard ph buffer of ph 4.0 , standard ph buffer of ph 7.0 , standard ph buffer of ph 9.0 , standard ph buffer of ph 10.0 , fluoride standard solution , 100 ntu calibration standard formazine , tss crm standard , oil and grease crm , ammonium standard solution , potassium hydrogen phthalate , bod 1000m g by l crm , rfc crm , sodium nitrite , potassium iodate , tri sodium phosphate dodechydrate , dpd oxalate , dpd sulphate pentahydrate , anhydrous dpd sulphate , anhydrous potassium dihydrogen phosphate , sodium sulphite , diethyl-p-phenylenediamine