# Can I use this calculation for 10 ppm?

Is this formula right

10 ppm = abs of sample/abs of standard x concentration of standard

I am confused…
UV spectrophotometer is the only option for me…

Dear Ashi.

That right…

10 ppm is 10 part in 1,000,000 part
10 g in 1,000,000 g ( 1 g in 100 kg)
10 g in 1,000,000 ml (10 g in 1,000 L)

If you want to calculate a quantity of Substance in ppm unit, You shall be prepare standard at a same concentration of sample that you can.

for Example

1. Standard Preparation 10 ppm of Paracetamol (10 mg/1L or 10 microgram / ml)

1.1 ) weigh 50 mg of Paracetamol dilute to 50 ml of diluent
( Conc 1 mg/ml or 1000 mcg / ml or 1000 ppm)
1.2 ) Trasfer 5 ml from 1.1) dilute to 50 ml of Diluent
( Conc 0.1 mg/ml or 100 mcg / ml or 100 ppm)
1.3 ) Trasfer 5 ml from 1.2) dilute to 50 ml of Diluent
( Conc 0.01 mg/ml or 10mcg / ml or 10 ppm)

Std Dilution (10 ppm) is
= % std/100 * 50 mg/50 ml 5 ml/50 ml 5ml/50ml*1000

Sample from swab tip (X mcg) and extract with 10 ml of diluent

Cal Quantity (ppm or mcg/ml) =

Abs of Sam/Abs of Std*% std/10050 mg/50 ml5 ml/50 ml5ml/50ml1000

pmm or mcg/ml from calculate is a quantity of paracetamol in 10 ml of sample preparation, not ppm from swab tip (swab area)

From PI-006-3 :
"7.11 Establishment of limit
7.11.3
b) No more than 10 ppm of any product will appear in another product "

10 ppm. is mean 1 g.of Product A appear in 100 kg of Product B
or 10 mg per 1L

So. For Determinatio of carry over. you must established acceptance limit base on 10 ppm of product A share on Total contact surface area and
set up limit per swab area, and then calculate concentration of residue in
Extraction volume
Example .

Not more than 10 ppm (1 g in 100 kg)
Manufacturing contact surface area is 1,000,000 square cm

limit per square cm = 1 * 1,0001000 (mcg) / 1,000,000 square cm
= 1 mcg per square cm
Swab area = 25 square cm,
you can meet Not more than 25
1= 25 mcg per swab
and Extraction volume = 10 ml
you can meet Not more than 25/10 = 2.5 mcg per ml or 2.5 ppm in your swab sample when determine with spectro.

Best Regards