Where is the ho-ru in a ho-rupipetto?
Alan Siegrist
I am translating a text that involves chemistry lab procedures but I have
come upon a bit that I am completely confused about.
There are numerous references to a ホールピペット, which from the Wikipedia
article:
http://ja.wikipedia.org/wiki/ホールピペット
I take to be a volumetric pipette.
http://en.wikipedia.org/wiki/Volumetric_pipette
OK, so far so good.
However, now I come upon this sentence:
試料溶液が自然落下しなくなったら、そのまま先を内壁に付けた状態で約15秒持ち
ホールピペットの上部をふさぎホール部分を緩めて、溜まった試料溶液を落とす。
When I was in chemistry lab working with volumetric pipettes, we were told
not to try to remove the last remaining bit in the tip of the pipette,
because it was calibrated assuming that a small amount would remain due to
surface tension. I suppose different pipettes could be calibrated in
different ways, though.
Anyway, I cannot understand what the ホール部分 is and how it could be
loosened. The volumetric pipettes I know of are made of single pieces of
glass and cannot be disassembled in any manner. Naturally, a rubber bulb can
be attached to the top, though.
Is this ホールピペット NOT an ordinary volumetric pipette, and if so, what
is it and what is the ホール部分?
Regards,
Alan Siegrist
Carmel, CA, USA
Benjamin Barrett
Matthew Schlecht
Dear All,
I am translating a text that involves chemistry lab procedures but I have
come upon a bit that I am completely confused about.
There are numerous references to a ホールピペット, which from the Wikipedia
article:
http://ja.wikipedia.org/wiki/ホールピペット
I take to be a volumetric pipette.
http://en.wikipedia.org/wiki/Volumetric_pipette
OK, so far so good.
However, now I come upon this sentence:
試料溶液が自然落下しなくなったら、そのまま先を内壁に付けた状態で約15秒持ち
ホールピペットの上部をふさぎホール部分を緩めて、溜まった試料溶液を落とす。
When I was in chemistry lab working with volumetric pipettes, we were told
not to try to remove the last remaining bit in the tip of the pipette,
because it was calibrated assuming that a small amount would remain due to
surface tension. I suppose different pipettes could be calibrated in
different ways, though.
Exactly. In my experience, there are two major types of calibration, and these will be marked on the actual pipette:
TD or T/D is "to deliver", and means you don't pump out that last little bit - it is calibrated for how much is delivered by the normal means. See:
http://www.brand.de/fileadmin/user/images/products/Laboratory_Glassware/bulb_pipettes/Aufschr_Vollpip_E.jpg
TC or T/C is "to contain", and with this type you blow out or rinse out the last little bit.
I also find the following at: http://www.coleparmer.com/catalog/0304_pdf/A-1210.pdf
Did you know...
A “to contain” pipette holds the exact volume of liquid specified.
A “to deliver/blow out” pipette must be allowed to drain, then the drop that remains in the tip must be blown out and added to the original delivery to equal the exact volume.
A “to deliver” pipette must be held vertically with the tip against the side of the receiving vessel and allowed to drain completely. The stated volume is obtained when draining stops. The “blow out” technique should not be used with this type of pipette.
Anyway, I cannot understand what the ホール部分 is and how it could be
loosened. The volumetric pipettes I know of are made of single pieces of
glass and cannot be disassembled in any manner. Naturally, a rubber bulb can
be attached to the top, though.
Is this ホールピペット NOT an ordinary volumetric pipette, and if so, what
is it and what is the ホール部分?
While puzzling about this, my mind glided onto the possibility of something like a "hole pipette" (previously unknown to me). However, some searching showed this to be a will o' the wisp. I think ホールピペット must be volumetric pipette.
Pipetting instruments such as the Transferpette® have separable tips, and maybe this is what is being referred to, i.e.:
http://www.brand.de/fileadmin/user/images/products/liquid_handling/Transferpette_S/tfps.jpg
HTH
Matthew Schlecht
Newark, DE, USA
Herman
>
> 試料溶液が自然落下しなくなったら、そのまま先を内壁に付けた状態で約15秒持ち
> ホールピペットの上部をふさぎホール部分を緩めて、溜まった試料溶液を落とす。
>
> Anyway, I cannot understand what the ホール部分 is and how it could be
> loosened. The volumetric pipettes I know of are made of single pieces of
> glass and cannot be disassembled in any manner. Naturally, a rubber bulb can
> be attached to the top, though.
ホール部分 is probably the bulge part, and 緩めて should probably be 暖
めて. Closing off the top and warming up the air inside (by gripping the
bulge in one's palm or the like) would cause the air to expand, pushing
out the last bit of liquid.
Herman Kahn
Alan Siegrist
> > 試料溶液が自然落下しなくなったら、その
> > まま先を内壁に付けた状態で約15秒持ち
> > ホールピペットの上部をふさぎホール部分
> > を緩めて、溜まった試料溶液を落とす。
> >
> > Anyway, I cannot understand what the ホール部分 is and how it could be
> > loosened. The volumetric pipettes I know of are made of single pieces
> > of glass and cannot be disassembled in any manner. Naturally, a rubber
> > bulb can be attached to the top, though.
>
> ホール部分 is probably the bulge part
That could be.
> and 緩めて should probably be 暖めて. Closing off the top and warming up
> the air inside (by gripping the bulge in one's palm or the like) would
cause the
> air to expand, pushing out the last bit of liquid.
This does solve the problem of trying to find some exotic type of pipette
that has some part that can be loosened, but I wonder if this "warming
method" would actually work in practice.
Warming up the pipette between your hands with the top closed might cause
the air inside to expand very slightly, but I wonder if this would be enough
to push out that drop of liquid at the tip. Even if it might work, it would
probably take a long time and be not very efficient.
One wonders why the directions would not simply direct the experimenter to
use a rubber bulb to "blow out" the drop if that was desired, since this
would be the most expedient method.
Alan Siegrist
> Check out http://www.chem.zenkyo.h.kyoto-u.ac.jp/operation/Operation_Guide_WMV/operation/frame/frame_06_wmv.html
> where the ホール部分 is the top half. There is an English translation of the page as well.
Thanks for finding that. From this, the bulge (or bulbous) part does seem to be the ホール部分 as suggested by Herman.
Benjamin Barrett
On Aug 11, 2011, at 1:11 PM, Alan Siegrist wrote:
> Benjamin Barrett writes:
>
>> Check out http://www.chem.zenkyo.h.kyoto-u.ac.jp/operation/Operation_Guide_WMV/operation/frame/frame_06_wmv.html
>> where the ホール部分 is the top half. There is an English translation of the page as well.
>
> Thanks for finding that. From this, the bulge (or bulbous) part does seem to be the ホール部分 as suggested by Herman.
Looking at this a bit more....
試料溶液が自然落下しなくなったら、そのまま先を内壁に付けた状態で約15秒持ちホールピペットの上部をふさぎホール部分を緩めて、溜まった試料溶液を落とす。
You're supposed to ホールピペットの上部をふさぎ - close off the top part - and then ホール部分を緩めて. It seems possible that the ホール部分 could be the hole at either end. If you're stopping up the top portion (with your forefinger), what is it that you are doing to the hole (at one of the ends) to (jostle?) the solution into coming out?
I don't understand what 先を内壁に付け means exactly, but it must fit into the equation...
Mika J.
ピペット先端を原液容器の内壁に付けてピペット外側の余分な液滴を擦り落とし、指と管の隙間から空気を入れたり止めたりして、液面のメニスカスの下面を標線の上縁か標線中央に合わせる
(I like the 擦り落とし part.)
So 内壁 must be that of 原液容器. The same page also has this:
上端を指で押さえて膨大部を手で温めたりして、残液を吹き出さなければならない。
So according to Matthew's list, it must be the “to deliver/blow out” pipette.
手の冷たいときはやりにくそうですね。
Mika Jarmusz 清水美香
English to Japanese Translator
http://inJapanese.us
Alan Siegrist
> The Japanese Wikipedia has the following:
> 残液を吹き出さなければならない。
>
> So according to Matthew's list, it must be the “to
> deliver/blow out” pipette.
So Herman's suggestion may be correct after all. I did not find any reference to this "warming" technique in English, but the prevalent types of pipettes seem to be different in Japan and in other countries, so the warming technique may be used only in Japan.
> 手の冷たいときはやりにくそうですね。
確かにそう。
助かりました。ありがとうございます。