EUROPEAN PHARMACOPOEIA 11.0 2.1.3. Ultraviolet ray lamps for analytical purposes
2.1. APPARATUS
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2.1.1. DROPPERS
The term ‘drops’ means standard drops delivered from a standard dropper as described below.
Standard droppers (Figure 2.1.1.-1) are constructed of practically colourless glass. The lower extremity has a circular orifice in a flat surface at right angles to the axis.
Figure 2.1.1.-1. –Standard dropper Dimensions in millimetres
Other droppers may be used provided they comply with the following test.
20 drops ofwater Rat 20 ± 1 °C flowing freely from the dropper held in the vertical position at a constant rate of 1 drop per second weighs 1000 ± 50 mg.
The dropper must be carefully cleaned before use. Carry out 3 determinations on any given dropper. No result may deviate by more than 5 per cent from the mean of the 3 determinations.
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2.1.2. COMPARATIVE TABLE OF POROSITY OF SINTERED-GLASS FILTERS
(1)Table 2.1.2.-1
Porosity number (Ph. Eur.)(2)
Maximum diameter of pores
in micrometres
Germany France United Kingdom
1.6 less than 1.6 5f – –
– 1 - 2.5 5 – 5
4 1.6 - 4 – – –
– 4 - 6 – 5 –
10 4 - 10 4f – 4
16 10 - 16 4 4 –
40 16 - 40 3 3 3
– 40 - 50 – – 2
100 40 - 100 2 2 –
– 100 - 120 – – 1
160 100 - 160 1 1 –
– 150 - 200 0 0 –
250 160 - 250 – – –
– 200 - 500 – 00 –
Special Uses
Diameters in micrometres
< 2.5 Bacteriological filtration
4 - 10 Ultra-fine filtration, separation of micro-organisms of large diameter
10 - 40 Analytical filtration, very fine filtration of mercury, very fine dispersion of gases
40 - 100 Fine filtration, filtration of mercury, fine dispersion of gases 100 - 160 Filtration of coarse materials, dispersion and washing of gases,
support for other filter materials
160 - 500 Filtration of very coarse materials, dispersion and washing of gases.
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2.1.3. ULTRAVIOLET RAY LAMPS FOR ANALYTICAL PURPOSES
Mercury vapour in quartz lamps is used as a source of ultraviolet (UV) light. A suitable filter may be fitted to eliminate the visible part of the spectrum emitted by the lamp. When the Pharmacopoeia prescribes in a test the use of ultraviolet light of wavelength 254 nm or 365/366 nm, an instrument consisting of a mercury vapour lamp and a filter that gives an emission band with maximum intensity at about 254 nm or 365/366 nm may be used.
Alternatively, lamps fitted with fluorescent tubes emitting UV light at 254 nm (narrow bandwidth) or with fluorescent tubes emitting broadband UVA light (315-380 nm ; long-wave UV light) can be used.
(1) The given limits are only approximate.
(2) The European Pharmacopoeia has adopted the system proposed by the International Organization for Standardization (ISO).
General Notices (1) apply to all monographs and other texts 17
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2.1.4. Sieves EUROPEAN PHARMACOPOEIA 11.0
The lamp used should be capable of revealing without doubt a standard spot of sodium salicylate about 5 mm in diameter on aTLC silica gel G plate Ror a standard band of sodium salicylate on a TLC or HPTLC plate, the spot or band being examined while in a position normal to the radiation.
For this purpose apply 5 μL of a 0.4 g/L solution ofsodium salicylate Rinethanol (96 per cent) R(3)for lamps of maximum output at 254 nm and 5 μL of a 2 g/L solution ofsodium salicylate Rinethanol (96 per cent) R(3)for lamps of maximum output at 365/366.
The distance between the lamp and the chromatographic plate under examination used in a pharmacopoeial test never exceeds the distance used to carry out the above-mentioned performance test.
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2.1.4. SIEVES
Sieves are constructed of suitable materials with square meshes. For purposes other than analytical procedures, sieves with circular meshes may be used, the internal diameters of which are 1.25 times the aperture of the square mesh of the corresponding sieve size. There must be no reaction between
the material of the sieve and the substance being sifted.
Degree of comminution is prescribed in the monograph using the sieve number, which is the size of the mesh in micrometres, given in parenthesis after the name of the substance (Table 2.1.4.-1).
Maximum tolerance(4)for an aperture (+ X) : no aperture size shall exceed the nominal size by more thanX, where :
X w
2 ( ) w
3 4 ( )
0.75 0.25
= +
w = width of aperture.
Tolerance for mean aperture (± Y) : the average aperture size shall not depart from the nominal size by more than ± Y, where :
Y w 27 1.6
= 0.98+
Intermediary tolerance (+ Z) : not more than 6 per cent of the total number of apertures shall have sizes between “nominal + X” and “nominal + Z”, where :
Z X Y
= +2
Wire diameterd: the wire diameters given in Table 2.1.4.-1 apply to woven metal wire cloth mounted in a frame. The nominal sizes of the wire diameters may depart from these values within the limitsdmaxanddmin. The limits define a permissible range of choice ± 15 per cent of the recommended nominal dimensions. The wires in a test sieve shall be of a similar diameter in warp and weft directions.
Table 2.1.4.-1 (values in micrometers)
Tolerances for apertures Wire diameters
Sieve numbers (Nominal dimensions of
apertures)
Maximum tolerance for
an aperture
Tolerance for mean aperture
Intermediary tolerance
Recommended nominal dimensions
Admissible limits
+ X ± Y + Z d dmax dmin
11 200 770 350 560 2500 2900 2100
8000 600 250 430 2000 2300 1700
5600 470 180 320 1600 1900 1300
4000 370 130 250 1400 1700 1200
2800 290 90 190 1120 1300 950
2000 230 70 150 900 1040 770
1400 180 50 110 710 820 600
1000 140 30 90 560 640 480
710 112 25 69 450 520 380
500 89 18 54 315 360 270
355 72 13 43 224 260 190
250 58 9.9 34 160 190 130
180 47 7.6 27 125 150 106
125 38 5.8 22 90 104 77
90 32 4.6 18 63 72 54
63 26 3.7 15 45 52 38
45 22 3.1 13 32 37 27
38 – – – 30 35 24
(3) Theethanol (96 per cent) Rused must be free from fluorescence.
(4) See the International Standard ISO 3310/1 (1975).
18 See the information section on general monographs (cover pages)