IP Ratings explained

IP RATING TABLE
Degree of Protection	1st Digit(Solid Objects)	2nd Digit(Liquids)
0	No Protection	No Protection
1	Protected against objects larger than 50mm	Drip Proof
2	Protected against objects larger than 12mm	Protected against direct sprays of water up to 15° from vertical
3	Protected against objects larger than 2.5mm	Protected against direct sprays of water up to 60° from vertical -light rain proof
4	Protected against objects larger than 1mm	Protected against water sprayed from all directions-light splash proof
5	Protected against dust limited ingress	Protected against low pressure jets of water from all directions -limited ingress permitted
6	Totally protected against dust	Protected against low pressure jets of water (use on ship deck) -limited ingress permitted
7	Not Defined	Protected against the effect of immersion between 150mm & 1 metre
8	Not Defined	Protected against long periods of immersion under pressure

pH Measurement theory and Electrodes

pH Measurement

The measurement of pH using a pH Electrode is an age old method that centres around
the perception of a substance as acidic or alkaline and is dependent on the concentration
of the hydrogen Ion (H+) within the substance.

The use of a pH electrode allows this measurement to be expressed in a meaningful way.

Derived from the Sorensen Equation the pH value is defined as a negative logarithm of the H+ concentration in a given solution.

A high H+ Concentration equals: 1mol/L = 10o pH = 0 (ACIDIC)

A low H+ Concentration equals: 10-14 mol/L pH=14 (ALKALINE)

It is therefore simple to measure the pH of a substance and compare it with other substances. pH 0 is extremely acidic, pH 14 is extremely alkaline and pH 7 neutral.

Measuring pH Values

Measuring the pH of a substance requires the use of a pH Electrode and a Reference Electrode. The pH Glass at the end of the electrode acts as the sensing part of the circuit.

The second part of the circuit is the reference electrode. This is a stable point that has a defined potential and is independent of the solution to be measured. The reference electrode fig is made up of a reference element that is commonly a Silver/Silver Chloride wire encased in a known electrolyte. The reference electrode then has a junction, which is the contact between the stable internal reference electrode and the solution to be measured. This is commonly a porous ceramic pin.

The evolution of pH electrodes came with the joining of the two separate electrodes to produce the COMBINATION pH ELECTRODE. The formation of the combination electrode can be seen below. The formation of the combination electrode still has the pH Glass membrane acting in the same way. The reference electrode is continually encased around the pH electrode. As the pH Glass comes into contact with an aqueous substance to measure, a gel layer forms on the membrane. This also happens on the inside of the glass layer. The pH value of the aqueous solution will either force Hydrogen Ions out of the Gel layer or into this layer. The Internal buffer in the glass electrode has a constant pH value and this keeps the potential at the inner surface of the membrane constant. The membrane potential is therefore the difference between the inner and outer charge. If you then factor in the reference electrode with its stable potential you have a combination pH electrode that encapsulates the measuring electrode and reference electrode.

P&R Labpak are able to offer a huge range of electrodes and through it’s electrode supplier Sentek can offer their equivalents which are less expensive and yet are the same or better quality.  Contact us on 0870 034 2055 or e-mail us at sales@prlabs.co.uk with your electrode enquiries.

 

How the pH Electrode Works

As the pH Glass comes into contact with an aqueous substance to measure, a gel layer forms on the membrane.
This also happens on the inside of the glass layer.

The pH value of the aqueous solution will either force Hydrogen Ions out of the Gel layer or into this layer.
The Internal buffer in the glass electrode has a constant pH value and this keeps the potential at the inner
surface of the membrane constant.

The membrane potential is therefore the difference between the inner and outer charge.
If you then factor in the reference electrode with its stable potential you have a combination
pH electrode that encapsulates the measuring electrode and reference electrode.

Visit www.prlabs.co.uk for more information or to contact us.  Check out our news pages for special offers – www.prlabs.co.uk/news

Whatman filter papers - Which one to use?

The download link below is a pdf document detailing which Whatman filter papers to use for which application.  Just click on the link below.

PDF download

If you require any help with filtration just contact our sales desk - sales@prlabs.co.uk or call us on 0870 034 2055.

Alternative Chemical Names

Below is a list of common chemical names and their actual chemical name.

Common Chemical Names

Common Name	Chemical Name
acetone	dimethyl ketone; 2-propanone (usually known as acetone)
acid potassium sulfate	potassium bisulfate
acid of sugar	oxalic acid
ackey	nitric acid
alcali volatil	ammonium hydroxide
alcohol, grain	ethyl alcohol
alcohol sulfuris	carbon disulfide
alcohol, wood	methyl alcohol
alum	aluminum potassium sulfate
alumina	aluminum oxide
antichlor	sodium thiosulfate
antifreeze	ethylene glycol
antimony black	antimony trisulfide
antimony bloom	antimony trioxide
antimony glance	antimony trisulfide
antimony red (vermillion)	antimony oxysulfide
aqua ammonia	aqueous solution of ammonium hydroxide
aqua fortis	nitric acid
aqua regia	nitrohydrochloric acid
aromatic spirit of ammonia	ammonia in alcohol
arsenic glass	arsenic trioxide
azurite	mineral form of basic copper carbonate
asbestos	magnesium silicate
aspirin	acetylsalicylic acid
baking soda	sodium bicarbonate
banana oil (artificial)	isoamyl acetate
barium white	barium sulfate
benzol	benzene
bicarbonate of soda	sodium hydrogen carbonate or sodium bicarbonate
bichloride of mercury	mercuric chloride
bichrome	potassium dichromate
bitter salt	magnesium sulfate
black ash	crude form of sodium carbonate
black copper oxide	cupric oxide
black lead	graphite (carbon)
blanc-fixe	barium sulfate
bleaching powder	chlorinated lime; calcium hypochlorite
blue copperas	copper sulfate (crystals)
blue lead	lead sulfate
blue salts	nickel sulfate
blue stone	copper sulfate (crystals)
blue vitriol	copper sulfate
bluestone	copper sulfate
bone ash	crude calcium phosphate
bone black	crude animal charcoal
boracic acid	boric acid
borax	sodium borate; sodium tetraborate
bremen blue	basic copper carbonate
brimstone	sulfur
burnt alum	anhydrous potassium aluminum sulfate
burnt lime	calcium oxide
burnt ochre	ferric oxide
burnt ore	ferric oxide
brine	aqueous sodium chloride solution
butter of antimony	antimony trichloride
butter of tin	anhydrous stannic chloride
butter of zinc	zinc chloride
calomel	mercury chloride; mercurous chloride
carbolic acid	phenol
carbonic acid gas	carbon dioxide
caustic lime	calcium hydroxide
caustic potash	potassium hydroxide
caustic soda	sodium hydroxide
chalk	calcium carbonate
Chile saltpeter	sodium nitrate
Chile nitre	sodium nitrate
Chinese red	basic lead chromate
Chinese white	zinc oxide
chloride of soda	sodium hypochlorite
chloride of lime	calcium hypochlorite
chrome alum	chromic potassium sulfate
chrome green	chromium oxide
chrome yellow	lead (VI) chromate
chromic acid	chromium trioxide
copperas	ferrous sulfate
corrosive sublimate	mercury (II) chloride
corundum (ruby, sapphire)	chiefly aluminum oxide
cream of tartar	potassium bitartrate
crocus powder	ferric oxide
crystal carbonate	sodium carbonate
dechlor	sodium thiophosphate
diamond	carbon crystal
emery powder	impure aluminum oxide
epsom salts	magnesium sulfate
ethanol	ethyl alcohol
farina	starch
ferro prussiate	potassium ferricyanide
ferrum	iron
flores martis	anhydride iron (III) chloride
fluorspar	natural calcium fluoride
fixed white	barium sulfate
flowers of sulfur	sulfur
'flowers of' any metal	oxide of the metal
formalin	aqueous formaldehyde solution
French chalk	natural magnesium silicate
French vergidris	basic copper acetate
galena	natural lead sulfide
Glauber's salt	sodium sulfate
green verditer	basic copper carbonate
green vitriol	ferrous sulfate crystals
gypsum	natural calcium sulfate
hard oil	boiled linseed oil
heavy spar	barium sulfate
hydrocyanic acid	hydrogen cynanide
hypo (photography)	sodium thiosulfate solution
Indian red	ferric oxide
Isinglass	agar-agar gelatin
jeweler's rouge	ferric oxide
killed spirits	zinc chloride
lampblack	crude form of carbon; charcoal
laughing gas	nitrous oxide
lead peroxide	lead dioxide
lead protoxide	lead oxide
lime	calcium oxide
lime, slaked	calcium hydroxide
limewater	aqueous solution of calcium hydroxide
liquor ammonia	ammonium hydroxide solution
litharge	lead monoxide
lunar caustic	silver nitrate
liver of sulfur	sufurated potash
lye or soda lye	sodium hydroxide
magnesia	magnesium oxide
manganese black	manganese dioxide
marble	mainly calcium carbonate
mercury oxide, black	mercurous oxide
methanol	methyl alcohol
methylated spirits	methyl alcohol
milk of lime	calcium hydroxide
milk of magnesium	magnesium hydroxide
milk of sulfur	precipitated sulfur
"muriate" of a metal	chloride of the metal
muriatic acid	hydrochloric acid
natron	sodium carbonate
nitre	potassium nitrate
nordhausen acid	fuming sulfuric acid
oil of mars	deliquescent anhydrous iron (III) chloride
oil of vitriol	sulfuric acid
oil of wintergreen (artificial)	methyl salicylate
orthophosphoric acid	phosphoric acid
Paris blue	ferric ferrocyanide
Paris green	copper acetoarsenite
Paris white	powdered calcium carbonate
pear oil (artificial)	isoamyl acetate
pearl ash	potassium carbonate
permanent white	barium sulfate
plaster of Paris	calcium sulfate
plumbago	graphite
potash	potassium carbonate
potassa	potassium hydroxide
precipitated chalk	calcium carbonate
Prussic acid	hydrogen cyanide
pyro	tetrasodium pyrophosphate
quicklime	calcium oxide
quicksilver	mercury
red lead	lead tetraoxide
red liquor	aluminum acetate solution
red prussiate of potash	potassium ferrocyanide
red prussiate of soda	sodium ferrocyanide
Rochelle salt	potassium sodium tartrate
rock salt	sodium chloride
rouge, jeweler's	ferric oxide
rubbing alcohol	isopropyl alcohol
sal ammoniac	ammonium chloride
sal soda	sodium carbonate
salt, table	sodium chloride
salt of lemon	potassium binoxalate
salt of tartar	potassium carbonate
saltpeter	potassium nitrate
silica	silicon dioxide
slaked lime	calcium hydroxide
soda ash	sodium carbonate
soda nitre	sodium nitrate
soda lye	sodium hydroxide
soluble glass	sodium silicate
sour water	dilute sulfuric acid
spirit of hartshorn	ammonium hydroxide solution
spirit of salt	hydrochloric acid
spirit of wine	ethyl alcohol
spirits of nitrous ether	ethyl nitrate
sugar, table	sucrose
sugar of lead	lead acetate
sulfuric ether	ethyl ether
talc or talcum	magnesium silicate
tin crystals	stannous chloride
trona	natural sodium carbonate
unslaked lime	calcium oxide
Venetian red	ferric oxide
verdigris	basic copper acetate
Vienna lime	calcium carbonate
vinegar	impure dilute acetic acid
vitamin C	ascorbic acid
vitriol	sulfuric acid
washing soda	sodium carbonate
water glass	sodium silicate
white caustic	sodium hydroxide
white lead	basic lead carbonate
white vitriol	zinc sulfate crystals
yellow prussiate of potash	potassium ferrocyanide
yellow prussiate of soda	sodium ferrocyanide
zinc vitriol	zinc sulfate
zinc white	zinc oxide

For help in sourcing the chemicals you need give us a call on 0870 034 2055 or visit our website on the link below.
P&R Labpak Website