Mar., I914
T H E J O U R N A L O F I , V D r S T R I A L A N D ENGIA%TEERINGCHEMISTRZ‘
zoo gallons per minute a n d seemed t o be t h e key t o t h e control of t h e mineral water basin. This spring was cleaned again in -4pri1, 1913,a n d now has a flow of about one gallon per minute. The water is strongly mineralized, being low in chlorides b u t high in sodium a n d magnesium bicarbonates. T h e water is a n excellent table water and is served at t h e spring. Old Red Spriizg-This spring is situated on Spring Avenue a n d was discovered in 1 7 j o or about as soon as t h e locality was visited by white men, being t h e next spring Eound after t h e discovery of t h e famous “High Rock.” I n 1784, the first b a t h house was erected 3n the property. From t h a t time up t o t h e acquirement of the spring by t h e Reserration Commission several b a t h houses had been built on t h e site of t h e old one a n d various improvements were made in t h e spring. The flow for many years was sufficient t o maintain t h e baths and allon- t h e water t o be bottled. T h e spring h a d a reputation for thegreat curative properties of its water a n d was a famous resort in the days of Saratoga’s popularity. When t h e state took over this property t h e b a t h houses. bottling house a n d equipment were old. crude a n d unsuitable for continuance under S t a t e ownership so the buildings were taken down. T h e spring itself was also in bad condition, t h e wooden tubing being neither sanitary nor permanent. I n July, 1912, it was GEYSERSPRING decided t o retube t h e spring, a n d t o avoid excavating a n eight inch steel casing was inserted into t h e m-ooden tubing, and t h e space between t h e two packed with concrete. After retubing, t h e natural flow was slightly greater t h a n before b u t was not enough t o meet t h e demands for bathing or bottling without resorting t o pumping. The spring is 2 2 feet deep a n d has a flow of about one quart per minute. The water is moderately mineralized averaging with t h a t of t h e Columbian. I t is one of t h e famous iron springs a n d derived its name from the red coloration due t o iron which t h e water contained. The lVew Red Spring is situated on this same property about I O O feet southeast of t h e Old Red Spring. I t was drilled in 1885 a n d is 60 feet deep. T h e water of this spring is high in iron content a n d is served t o t h e public. I t has a flow of about two quarts per minute and in mineralization it approaches t h e TVashington. W u s h i i z g t o n Spriitg-This spring is situated on South Broadway just above Congress Park in t h e old Clarendon Hotel property. I t was discovered in 1806 a n d is 1 7 0 feet deep. The water does not flow a t t h e surface of t h e ground b u t is obtained b y pumping. T h e spring
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h a d a celebrated reputation for its iron content and was used t o a great extent. The property does not belong t o t h e Commission b u t is owned b y t h e St. Peters Catholic Church. Various scientific observations, which have been taken, show an improrement in this spring. T h e Columbiuit Spring is located in t h e famous Congress Park, just west of t h e park entrance and on Broadway. I t is one of t h e oldest mineral springs having been opened by a pioneer, Gideon P u t m a n , in 1806. This is also a chalybeate water being closely connected with t h e T a s h i n g t o n Spring as like changes in water levels are recorded simultaneously in both springs. I n April, 1913,t h e uooden tubing mas cleaned and a n iron casing inserted i n it so as t o insure sanitary conditions. The spring is eleven feet deep and its waters are moderately mineralized. STATE
HYGIEXIC LABORATORY
ALBANY.A-Ew YORK
THE DETERMINATION OF HARDNESS IN NATURAL WATERS By C L A R E K C E
BAHLMAhs
Received December 1, 1913
Lime hardness, magnesium hardness, and total hardness constitute t h e three primary determinations in industrial water analyses. -4n allcalimetrical method for total hardness b y use of soda reagent is described in t h e American Public Health Association’s Standard Llethods of TTater Analysis. Mention is made t h a t errors due t o solubility of t h e precipitated calcium and magnesium salts are not entirely obviated in this method, and t h a t t h e most accurate figure for total hardness is t h a t computed from t h e results for calcium a n d magnesium. This is true when these bases are determined gravimetrically, b u t when t h e magnesium is determined by Pfeifer a n d Wartha’s lime water method as described in t h e 190j edition of Standard AIethods, t h e results are unsatisfactory. For this reason undoubtedly, this method has not been inserted in t h e 1912 edition of t h e above publication; in fact no volumetric method is given for either calcium or magnesium. For many industrial purposes, rapidity in arriving a t results is preferred to extreme accuracy, and simple volumetric methods are entirely satisfactory for ordinary purposes provided t h e deficiencies and limits of accuracy of t h e method are known. This paper is a summary of a n investigation t o ascertain t h e accuracy of results obtained by certain volumetric procedures for calcium, magnesium a n d total hardness. The tests were made upon fifteen samples of natural waters obtained from nearby rivers, springs and wells. a n d showing wide ranges in calcium a n d magnesium content as well as in organic matter. C A LCI L-11 H A R D N E S S
The ease of manipulation and accuracy of t h e permanganate titration of calcium oxalate suggests its applicability in water analysis. Depending upon t h e hardness of t h e water, volumes of I O O cc. t o joo cc. will give workable precipitates. Fifteen waters ranging
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T H E J O C R N A L OF I N D C S T R I A L A N D E-YGINEERING C H E M I S T R Y
in lime hardness from 33.8 t o 360. j parts per million C a C 0 3 were examined. I n only one instance did t h e volumetric result vary f r o m t h e gravimetric by more t h a n 2 . 5 parts per million C a C 0 3 ; t h e average variation for t h e 1 5 samples was only 1.2 parts per million. T h e greatest percentage error was 3 . 2 per cent and, as a n average, 99.6 per cent of t h e gravimetric results was found by t h e volumetric procedure. These results are in entire accord with those reported by R. B. Dole,l who states t h a t it is possible t o estimate calcium volumetrically t o within I p a r t per million (2.5 parts per million C a C 0 3 ) . MAGNESIUM HARDNESS
T h e principle of Pfeifer a n d Wartha's method* for magnesium is t h a t when lime water is added t o a neutral solution of calcium a n d magnesium salts, t h e calcium salts remain unaltered while those of magnesium are precipitated as hydroxide, t h e lime water consumed being a measure of t h e magnesium present. T h e waters tested ranged in magnesium hardness from 1 5 t o 295.6 parts per million, expressed as a n equivalent a m o u n t of CaC03. T h e same volume of lime water was added t o all of these waters, a n d consequently t h e percentage of t h e added lime water consumed in t h e reaction increased as t h e magnesium hardness increased. If t h e accuracy of this method depends solely upon excess of precipit a n t , t h e n we should expect t h e results t o approach nearer t o t h e t r u e figures as t h e percentage of t h e lime water consumed in t h e reaction is decreased. T h e results, however, showed no relation whatsoever between excess of precipitant a n d accuracy of t h e volumetric results. On 4 samples (magnesium content from I j . 0 t o 20.9 p. p. m.) t h e percentage of added lime water theoretically needed t o precipitate t h e magnesium varied only from 2.8 per cent t o 3. 9 per cent, yet t h e volumetric results ranged from 60 per cent t o 86.1 per cent of t h e gravimetric amounts. Of two samples of practically t h e same magnesium content (21.8 a n d 23.0 p. p. m.), t h e volumetric result was in one case 82.6 per cent and, in t h e other, 113 per cent of t h e t r u e figure. T h e magnesium hardness was determined twice on 6 of t h e samples, using 2 5 cc. a n d jo cc. of t h e lime water. I n this way t h e effect of varying excesses of precipitant upon t h e accuracy was studied when working with t h e same water. With 3 of these samples, t h e best results were obtained where t h e lesser percentage of lime water was theoretically required in t h e reaction, b u t with t h e other samples just t h e reverse was true. I n t h e whole series, only 6 determinations gave results within I O per cent of t h e correct figures, a n d these showed a variation in the percentage of added lime water theoretically needed of from 6.1 per cent t o 57.6 per cent. An excess of lime water is undoubtedly necessary and, while further s t u d y upon waters of the same general character might reveal certain limits of excess giving optimum results, it appears f r o m t h e above work t h a t t h e amount of excess varies with t h e nature 1 2
Geological Survey,' Water Supply Paprr 836, 28. 2. anal. Chem., 1902, 199.
Q 1 . 6, No. 3
of t h e water. Even under t h e best conditions, magnesium hydroxide is appreciably soluble, causing low results. Another factor involved is the presence a n d celative concentration of other dissolved salts a n d organic matter. It is needless t o s t a t e t h a t no reliance can be placed upon any procedure exhibiting discrepancies such as shown above by t h e lime water method for magnesium. TOTAL HARDNESS
T h e range in total hardness of t h e 1 5 waters tested was from 48.8 t o 655.5 parts per million in terms of C a C 0 3 . For waters of low or medium hardness 0.04 N soda reagent and 0 . 0 2 N HzS04 were used, with harder waters, 0.1 N soda reagent a n d 0.1 N acid. T h e original titer of t h e soda reagent in terms of standard acid was determined not only by direct t i t r a t i o n b u t by a blank determination on distilled water conducted under conditions identical with those t o which t h e sample was subjected. As a n average, when basing t h e value of t h e soda reagent upon t h e direct titration, only 83.7 per cent of t h e gravimetric total hardness was found, b u t on t h e basis of t h e blank determination, 95.8 per cent of t h e true total hardness was found by t h e volumetric method. The necessity of making a control determination in all cases is therefore indicated. The same volume of soda reagent was added t o these waters a n d i t follows t h a t t h e percentage of added alkali consumed increased as t h e total hardness increased. When only 7 . 2 per cent of t h e precipitant was used up in t h e reaction, t h e volumetric result was 100.4 per cent of t h e gravimetric, a n d t h e percentage of t h e t r u e amounts found by t h e volumetric method decreased in fairly regular amounts as t h e percentage of soda reagent required for t h e reaction increased. When a s much as 7 9 . 7 per cent of t h e added alkali was consumed, only 76.8 per cent of t h e gravimetric total hardness was obtained by t h e volumetric method. It is evident from t h e above t h a t low results are ta be attributed t o insufficient excess of t h e precipitant. Several of t h e samples, on which 50 cc. of 0.04 N soda reagent had been used, were examined again, using 2 5 cc. of 0.1 N soda reagent. This trial indicated t h a t t h e best result o n a n y one sample was always obtained where the largest excess of alkali was present. Twenty-five determinations were made upon t h e I j waters and all results were within 5 per cent of t h e t r u e figures when not over 35 per cent of t h e soda reagent was consumed in t h e reaction. The relationship existing between t h e percentage of added soda reagent theoretically required in t h e reaction and t h e accuracy of t h e volumetric result for total hardness is shown in t h e following table: Per cent of added soda reagent theoretically required *lo 10-20 20-30 30-40 40-60 60-80
N o of determinations 2 6
4 4 4 5
Average per cent of gravimetric total hardness found by volumetric method io0 4 99 I 97 5 96 3 94 1 a9 1
I t appears from this table t h a t t h e best volumetric
Mar., 1914
T H E J O U R N A L O F I - V D L - S T R I A L AiYD E N G I N E E R I N G C H E M I S T R Y
results are obtained when t h e soda reagent is added i n such quantities t h a t not more t h a n 2 0 per cent of i t enters into t h e reaction, a n d t h a t t h e results are within 5 per cent of t h e t r u e amounts when not more t h a n 40 per cent of t h e alkali is used up. IlAGNESIUhl HARDNESS BY DIFFEREXCE
It has been shown t h a t t h e soda reagent method for total hardness is quite satisfactory for ordinary work if care be t a k e n t o have sufficient excess of t h e alkali present, a n d t h a t t h e permanganate titration for calcium is very accurate. When t h e magnesium is computed b y difference, i t suffers from t h e errors of t h e 2 direct methods a n d low results are t o be expected because t h e total. hardness figures are themselves low, due t o t h e appreciable solubility of normal calcium carbonate a n d magnesium hydroxide. With certain waters, however, very close results can be obtained b y this method. Seven of t h e samples, showing a range in hardness encountered in t h e Ohio River a t this locality (48 t o 130 p. p. m . total hardness; I j t o 37 p. p. m. magnesium hardness), gave very satisfactory results for magnesium b y difference, t h e average percentage of t h e t r u e a m o u n t being 98.6 per cent. With waters ranging in total hardness from 136 t o 6 j j . j p. p. m. a n d in magnesium hardness from 63.8 t o 2 9 j . 6 p. p. m., however, t h e average accuracy was b u t 90.3 per cent. I n such hard waters a comparatively small percentage error i n t h e t o t a l hardness affects t h e magnesium t o a greater extent, especially if t h e sample contains a relatively small quantity of this base in comparison t o t h e lime content. It appears t h e n , t h a t with comparatively soft waters a procedure, whereby t h e total hardness a n d calcium hardness are determined volumetrically as outlined a b o v e a n d t h e magnesium b y difference, is satisfactory for ordinary purposes. This method can also be applied t o hard waters t h e general character of which is familiar t o t h e analyst, provided he applies a correction factor determined b y occasional comparisons of t h e volumetric with gravimetric results. H a r d waters very low in magnesium as compared t o calcium content will give t h e least satisfactory results, a n d t h e gravimetric method for magnesium must be resorted t o in this case if accurate figures are desired. SGMMARY
I. N o volumetric methods for calcium or magnesium are given in t h e 1912 edition of Standard Methods of Water Analysis. 11. For ordinary purposes, rapidity is preferred to extreme accuracy, a n d volumetric methods are desired. 111. T h e estimation of calcium b y titration with permanganate is easily a n d quickly performed a n d t h e results are very accurate. 11‘. T h e estimation of magnesium with lime water is entirely unreliable. V. T h e best results for t o t a l hardness are obtained when less t h a n 2 0 per cent of t h e soda reagent is used up in t h e reaction, a n d t h e results will be within j per cent of t h e t r u e a m o u n t when not more t h a n 40 per cent of t h e soda reagent is consumed. T h e original
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strength of t h e soda reagent must be determined b y a blank determination. lr1. An ordinarily satisfactory procedure for examination of waters of low or medium hardness consists in determining t h e total hardness with soda reagent. t h e lime hardness with permanganate and ascertaining t h e magnesium content by difference. This method can also be used for hard waters b y applying a correction factor. For very hard waters containing only small amounts of magnesium, this base must be determined gravimetrically if accurate results are desired. CHEMICAL LABORATORIES, DEPARTMENT O F HEALTH CINCINNATI, OHIO
THE QUANTITATIVE ESTIMATION OF THE SALTSOLUBLE P R O T E I N S I N W H E A T FLOUR By GEO. A. OLSON Received October 2 , 1913
I t has been repeatedly pointed out’ t h a t t h e strengths of alcohol suitable for t h e extraction of gliadin from flour, extracts other proteins besides gliadin. That this is unquestionably t r u e was brought out b y t h e writer in a previous article2 on t h e estimation of gliadin in flour a n d gluten where i t was found t h a t t h e direct method for t h e extraction of t h e alcohol-soluble proteins gave considerably higher yield of nitrogen (38.3 per cent more) t h a n could be obtained b y either t h e indirect or coagulation methods. Likewise it has been found3 t h a t I per cent sodium chloride extracts, besides edestin, leucosin a n d amino bodies, a n d some gliadin. Osborne4 states t h a t gliadin is practically insoluble in I O per cent sodium chloride. F r o m a quantitative point of view, i t appears reasonable t h a t a I O per cent salt solution is t h e proper strength t o use. B u t we find t h a t a I O per cent salt solution is impractical t o work with owing t o t h e large a m o u n t of salt present, a n d for this reason Teller,j a n d subsequently others, adopted strengths less objectionable. It was admitted b y Teller a n d confirmed later b y others b y indirect methods t h a t gliadin is partly soluble in I per cent salt solution, b u t just how soluble gliadin is no one has stated, nor even corrected for, when using this strength solution. A correction hks been made for amide bodies b y assuming t h a t amide bodies are not precipitated by phosphotungstic acid. I n t h e article referred t o , t h e writer has pointed o u t t h e method for t h e estimation of t h e gliadin extracted b y a I per cent salt solution a n d in connection with this t h e following experiments were conducted with t h e view of establishing a correct method for t h e estimation of edestin a n d leucosin proteins in flour. Three different methods of procedure were adopted for t h e estimation of t h e salt-soluble proteins in flour. T h e first series of results was obtained by t h e method which is annually recommended t o be followed b y t h e 2
U.S. Dept. of Agr.. Bur. of Chem., Bull. KO. 81 and 90. THISJOURNAL, 6, 91i.
a
A r k . Bull. No. 63;U. S. Dept. Agr., Bur. of Chem., No. 81 and No. 90
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“ T h e Proteins of the Wheat Kernel.” Ark. Bull. N o . 63.
1
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