ACQUA PURA ED ULTRAPURA - CLASSIFICAZIONI

 

L'acqua purificata viene comunemente usata in molte industrie e organizzazioni scientifiche, per usi analitici o nei processi produttivi. Pertanto  per favorirne un utilizzo più adeguato, alcune organizzazioni internazionali hanno stabilito degli standard di qualità per ogni tipo di appplicazione: ISO (the International Organisation for Standardisation ) ASTM (the American Society for Testing and Materials) NCCLS (the National Committee for Clinical Laboratory Sandards) the Farmacopoeia

 

Specifiche secondo International Organisation for Standardisation

Per acqua ad uso laboratorio si fa riferimento a ISO 3696: 1987

 

Parametro                                                                       Grado 1              Grado 2              Grado 3

 

· pH - valore a 25°C                                                          N/A                      N/A                      5-7.5

· Conducibilità elettrica specifica a 25°C (microS/cm)      0,1                       1                          5

· Carbonio totale ossidabile da O2 (mg/lt)                        N/A                      0,08                     0,4

· Assorbanza unitaria max. a 250 nm                               0,001                  0,01                     non spec.

· Residuo fisso a 110°C (mg/lt)                                        N/A                      1                          2

· Silice max (mg/lt)                                                           0,01                     0,02                     non spec.

 

 

Specifiche secondo the American Society for Testing and Materials

Standard di riferimento per acqua di GRADO REAGENTE

 

Parametro                                         Tipo I*                   Tipo II**              Tipo III***            Tipo IV

 

· pH - valore a 25°C                           -                              -                          -                          5-8

· Conducibilità elettrica

  specifica a 25°C (microS/cm)           0,056                      0,1                       0,255

· Resistività elettrica specifica

  (MOhm.cm)                                       18                          10                        4                         0,2

· TOC (microg/lt)                                100                         150                     200                      no lim.

· Sodio max (microg/lt)                       1                             5                         10                       50

· Cloruri max (microg/lt)                     1                             5                          10                       50

· Silice max (mocrog/lt)                      3                             3                          500                     no lim.

 

*    Si richiede filtrazione su membrana 0,2 micron

**   Preparata per distillazione

*** Si richiede filtrazione su membrana 0,45 micron

 

Laddove vi siano da effettuare controlli microbiologici, fa seguito una ulteriore classificazione

 

Parametro                                                                      Tipo A                  Tipo B                 Tipo C

 

· Conta totale batterica max (UFC/100ml)                      1                          10                        1000

· Endotossine max (IU/ml)                                              0,03                     0,25                      -

 

 

Specifiche secondo the National Committee for Clinical Laboratory Sandards (1988)

 

Parametro                                                                       Tipo I                   Tipo II                 Tipo III

 

· Batteri (UFC/100ml)                                                       <10                    <1000                  N/A

· pH - valore a 25°C                                                         N/A                     N/A                      5-8

· Resistività elettrica specifica (MOhm.cm)                      >10                    >1                        >0,1

· Silice max (mg/lt)                                                           < 0,05                0,1                       < 1

· Solidi Totali max (mg/lt)                                                  0,1                     1                           5

· Carbonio totale ossidabile da O2 (mg/lt)                        < 0,05                < 0,2                    < 1

 

 

Specifiche secondo Farmacopea Europe a e USF

Requisiti delle acque purificate per iniezione in corpo

 

Parametro                                                                          EP                             USP

 

NITRATI                                                                          < 0,2 ppm

METALLI PESANTI                                                         < 0,1 ppm

TOC                                                                                 < 500 mg/lt C            < 500 mg/lt C

CONDUCIBILITA' ELETTRICA SPECIFICA A 25°c         < 4,3 microS/cm       < 1,3 microS/cm

BATTERI                                                                          < 100 UFC/ml           < 100 UFC/ml