NHOM PHOSPHAT KHO  

Aluminii phosphas siccum

AlPO4. xH2O P.t.l: 122.0 (khan)

Nhom phosphat kho chu yeu la nhom phosphat a hydrat hoa, phai cha t 94,0% en 102,0% AlPO4 tnh tren che pham a nung.

Tnh chat  

Bot mau trang hay gan trang. Rat kho tan trong nc, thc te khong tan trong ethanol 96%, tan trong cac dung dch loang cua acid vo c va kiem hydroxyd.

nh tnh  

Dung dch S: Hoa tan 2,00 g che pham trong dung dch acid hydrocloric 2 M (TT) va pha loang thanh 100 ml vi cung dung moi.

Dung dch S cho phan ng ac trng cua ion nhom va phan ng B cua ion phosphat (Phu luc 8.1).

o trong va mau sac cua dung dch

Dung dch S phai trong (Phu luc 9.2) va khong mau (Phu luc 9.3, phng phap 2)

pH  

Hon dch che pham 4% trong nc khong co carbon dioxyd (TT) co pH t 5,5 en 7,2 (Phu luc 6.2).

Kha nang trung hoa  

Can 0,50 g che pham, them 30 ml dung dch acid hydrocloric 0,1 M (C) 37 oC va duy tr nhiet o 37 oC trong 15 phut, khuay lien tuc, pH cua hon hp nay 37 oC sau 15 phut phai t 2,0 en 2,5 (Phu luc 6.2).

Arsen  

Khong c qua 1 phan trieu (Phu luc 9.4.2).

Dung 1,0 g che pham th theo phng phap A

Kim loai nang  

Khong c qua 20 phan trieu (Phu luc 9.4.8).

Hoa tan 1,0 g che pham trong dung dch acid hydrocloric 1 M (TT) va pha loang thanh 20 ml bang dung dch acid hydrocloric 0,1 M (TT). Lay 12 ml dung dch thu c e th theo phng phap 1. Dung dung dch ch mau 1 phan trieu (TT) e chuan b mau oi chieu.

Clorid  

Khong c qua 1,3% (Phu luc 9.4.5).

Hoa tan 50,0 mg che pham trong 10 ml dung dch acid nitric loang (TT) va pha loang thanh 200 ml bang nc. Lay 15 ml dung dch va tien hanh th.

Sulfat  

Khong c qua 0,6% (Phu luc 9.4.14).

Lay 8 ml dung dch S, pha loang vi nc thanh 100 ml. Lay 15 ml dung dch va tien hanh th.

Phosphat tan  

Khong c qua 1,0% tnh theo PO43-.

Dung dch th: Lac 5,0 g che pham vi 150 ml nc trong hai gi, loc va ra pheu loc bang 50 ml nc. Tap trung dch loc va nc ra, them nc va u 250,0 ml. Pha loang 10 ml dung dch nay vi nc thanh 100,0 ml.

Dung dch oi chieu (1): Hoa tan 2,86 g kali dihydrophosphat (TT) trong nc va pha loang thanh 100 ml bang nc.

Dung dch oi chieu (2): Pha loang 1 ml dung dch oi chieu (1) thanh 5 ml bang nc.

Dung dch oi chieu (3): Pha loang 3 ml dung dch oi chieu (1) thanh 5 ml bang nc.

Cach tien hanh: Lay 5,0 ml cua moi dung dch tren, them vao moi dung dch 4 ml dung dch acid sulfuric 1 M (TT), 1 ml dung dch amoni molybdat (TT), 5 ml nc va 2 ml dung dch co cha 0,10 g 4-methylaminophenol sulfat (TT), 0,5 g natri sulfit khan (TT) va 20,0 g natri metabisulfit (TT) trong 100 ml nc. Tron eu, e yen trong 15 phut va them nc va u 25 ml. e yen tiep 15 phut va o o hap thu (Phu luc 4.1) cua dung dch bc song 730 nm.

Tnh ham lng phosphat tan t ng cong chuan c thiet lap bi cac dung dch oi chieu (1), (2) va (3).

Mat khoi lng do nung

T 10,0 en 20%.

Dung 1,000 g, nung 800 C en khoi lng khong oi.

nh lng  

Hoa tan 0,400 g che pham trong 10 ml dung dch acid hydrocloric 2 M (TT) va pha loang vi nc thanh 100,0 ml. Lay 10,0 ml dung dch thu c, them 10,0 ml dung dch natri edetat 0,1 M (C) va 30 ml hon hp ong the tch cua dung dch amoni acetat (TT) va dung dch acid acetic loang (TT). un soi trong 3 phut, lam lanh. Them 25 ml ethanol 96% (TT) va 1 ml dung dch dithizon 0,025% (kl/tt) mi pha trong ethanol 96% (TT). Chuan o lng natri edetat 0,1 M tha bang dung dch kem sulfat 0,1 M (C) en khi mau chuyen sang hong.

1 ml dung dch natri edetat 0,1 M (C) tng ng vi 12,20 mg AlPO4.

Bao quan  

Trong bao b kn.

Loai thuoc

Khang acid da day.