!YFN'gÕÉ;ÖÇçRàûÕ¥õ?å×&6ú׺!O²Á:Ø
;HÁÆt=±e¹tÉÜU1±YòFÑeÙ¯íçW»IôUQ¥Ê£÷DÁíTð¹$Cá@
*
³B48 SAFETY DATA SHEET Revision Date 25-Apr-2019 Revision Number 4 1. While it doesn't appear to dissolve in ethanol , EBT will turn it red if added. acid, sodium salt; C.I. Hazard Identification Hazardous in case of skin contact (irritant), of eye contact (irritant), of inhalation. Please contact Fisher Scientific for shipping information. Ph Eur - Find MSDS or SDS, a COA, data sheets and more information. Chrome Black TX. MATERIAL SAFETY DATA SHEET ERIOCHROME BLACK T (C.I.NO.14645) (Solochrome Black T) MSDS CAS: 1787-61-7 Section 1: Chemical Product and Company Identification Synonyms: MATERIAL SAFETY DATA SHEET Date Printed: 10/20/2006 Date Updated: 01/29/2006 Version 1.4 Section 1 - Product and Company Information Product Name ERIOCHROME BLACK T, A.C.S. JÐøÏQɶÂíÌáþû¿:jPí®ûØ{pßY(QéÓ,«[ÜTaÐÞéò¾é1i'~RW>³BQÇWÛß;ë/Æÿîá¤Â>¿«S#ÒܢĢ3 Precautionary statement(s ) P261 P305 + P351 + P338 Supplemental Hazard Statements ... Palatine Chrome Black 6BN Mordant Black 17 Eriochrome® Blue Black R Formula : C20H13N2NaO5S Molecular Weight : 416,39 g/mol S71643 Skip to page content; Skip to site menu on this page. NSC7223. TOP âºâº Part A & B - Research & Laboratory Chemicals âºâº Organic Intermediates âºâº Dyes, Stains & Indicators âºâº Eriochrome Black T extrapure AR 40876 (054965) Eriochrome Black T extrapure AR ¢¸@÷ÌøÈ µ ÁY^ÙI!Þ9É¡>¹køæ¥ùå§Æ/*H[½ÔÂrºÔjµÍÌY¶vöf/3÷DCÝnÇyNæÎ52¥"© ʲ¦Ì¨åT0åIÙP©ÅåDͤ¦P!75J
R>9µò¥ì(*ò£ì)K*ZDͦ¦QK)j5ZFPnÔ\Ê )wÊN t)¥GéS£¨ÑÔÊQc)DRó)#jur¡ÆS©Ê2¡&PI Solochrome Dark Blue CAS No 2538-85-4 MATERIAL SAFETY DATA SHEET SDS/MSDS. As an ACS grade quality reagent, its chemical specifications are the de facto standards for chemicals used in many high-purity applications and typically designate the highest quality chemical available for laboratory use. 1787-61-7. Chemical Database Eriochrome Black T Identifications. §ªF 0;¦àX54èÉa»å]JèR*D\!ÈéèÒSgÑÇõÍ×"¶Åú$#âî;qù±1jÉo?"b'Yh#Ä÷Y(a3ªÝ|¨àpþ÷i(Ť®ÍÏ*Hß¼¼ä³°ò
ÐÑõ³ÉÌsö¤$£¤ÏSrsr³ÓÖ¯DAupú. Eye: Emergency Number: 201-796-7100 Eriochrome Black T is blue, but turns red in the presence of metals. Section 1 - Chemical Product and Company Identification fication . Company Identification: Warning! : ST97, ST97-100, ST97-500 Synonyms None Recommended Use Laboratory chemicals. Solochrome Black. : E512-25 CAS-No 1787-61-7 Synonyms Superchrome Black TS; 1-(1-Hydroxy-2-naphthylazo)-6-nitro-2-naphthol-4-sulfonic acid sodium salt; Mordant Black 11 (Certified) In this case, Eriochrome Black T is able to detect calcium, aluminium and magnesium by turning from a blue/black protonated form to a red complexed form. Bioaccumulative potential Eriochrome® Black T, ACS (1787 -61 -7) Bioaccumulative potential Not established. 2-Naphthol-4-sulfonic acid, sodium salt. MSDS Name: Eriochrome Black T, Indicator Grade Catalog Numbers: AC228360000, AC228360010, AC228360250, AC228361000, AC228365000, E512-25, S71643 Synonyms: 3-Hydroxy-4-(1-hydroxy-2-naphthlyazo)-7-nitro-1-naphthalene sulfonic acid, sodium salt; C.I. ERIOCHROME BLACK T, 1787-61-7, Complexometric Indicators, C20H12N3NaO7S by Loba Chemie, India 1-Naphthalenesulfonic acid,3-hydroxy-4-[(1-hydroxy-2-naphthalenyl)azo]-7-nitro-, monosodium salt. EBT is blue in a buffered solution at pH 10. 1 Reagent Lane Eriochrome (TM) Black T, also known as Solochrome Black T or ET-00, is a complexometric indicator and an azo dye used as an indicator in an EDTA titration. High purity, submicron and nanopowder forms may be considered. Chronic: Other adverse effects Chrome Black T. Chrome Black TK. Applications When used as an indicator in an EDTA titration, the characteristic blue end-point is reached when sufficient EDTA is added and metal ions form complexes with the EDTA instead of the Eriochrome. May cause irritation of the digestive tract. Product name: Eriochrome Black T Contact Information: Radchem cc PO Box 166982 Brackendowns Alberton 1454 Telephone : 011 867 3726 / 2864 2. Chrome Black ET; Eriochrome Black T; Chrome Black T; Solochrome For International CHEMTREC assistance, call: 703-527-3887. Mobility in soil No additional information available 12.5. Prolonged or repeated skin contact may cause dermatitis. It turns red when it forms a complex with calcium , magnesium , or other metal ions. In its protonated form, Eriochrome Black T is blue, but turns red when it forms a complex with calcium , magnesium , or other metal ions. Potential Health Effects Unusual fire and explosions hazards ⢠Emits toxic fumes under fire conditions. May cause respiratory tract irritation. Solochrom dark blue indicator MSDS Section 1: Chemical Product and Company Identification Product Name: Solocrome dark blue indicator Catalog Codes: 11721 CAS#: 2538-85-4 RTECS: Not available. Application Eriochrome ® Black T has been used to determine the concentration of Ca 2+ using complexometric titration method. Mordant Black 11, monosodium salt; Acid Chrome Black ET; Eriochrome Black T; Chrome Black T; Solochrome Black T. Catalog Numbers: It functions as an acid-base indicator. :N/A C20H12N3NaO7S Specific Properties and Impurities [Typical levels]: Loss on drying ⤠7% Absorptivity 1%/1cm @ pH 10 Ammonia Lambda max. ô¹¯qº\5ÇU²xÚ Eriochrome black T (C.I. Ingestion: Eriochrome Black T, Reagent, ACS, also known as Solochrome Black T, is a complexometric indicator used as an indicator in EDTA titration. sV[ë Skin: Preliminary testing of the product before use Ungraded products supplied by LabChem are indicative of a grade suitable for gene Slightly hazardous in case of CAS1787-61-7 Eriochrome Black T, Indicator Grade 3-Hydroxy-4-(1-hydroxy-2-naphthlyazo)-7-nitro-1-naphthalene sulfonic acid, sodium salt; C.I. 14645, Chrome black T Chem- Supply Pty Ltd does not warrant that this product is suitable for any use or purpose. Eriochrome ® Black T is used as an indicator for complexometric titrations. Synonyms: Palatine Chrome Black 6BN Company Identification: LabChem, Inc. 200 William Pitt Way Pittsburgh, PA 15238 Company Phone Number: (412) 826-5230 40876 Eriochrome Black T extrapure AR (Solochrome black T) 1787-61-7 Molecular Formula : C20H12N3NaO7S Molecular Weight : 461.39 irritation. ERIOCHROME BLACK T Prepared 30/11/01 By Dr. B. Dunlevy Page 2 of 4 Special fire fighting procedures ⢠Wear self-contained breathing apparatus and protective clothing to prevent contact with skin and eyes. Schultz No. MSDS Name: Eriochrome Black T, Indicator Grade Catalog Numbers: E/0100/46, E/0100/48 Synonyms: 3Hydroxy4(1hydroxy2naphthlyazo)7nitro1naphthalene sulfonic acid, sodium salt; C.I. Material Safety Data Sheet Solochrome black T MSDS Section 1: Chemical Product and Company Identification Product Name: black T Catalog Codes: 11720 CAS#: 1787-61-7 RTECS: QK2197000 TSCA: TSCA 8(b) inventory: Solochrome black T CI#: 14645 Synonym: Mordant Black 11, Solochrome Black, Eriochrome Black T, Chrome Black T, Chrome Black PB; REAGENT, & Product Number 858390 Brand SIAL Company Sigma-Aldrich Canada, Ltd solution Clarity of solution Passes test ACS Appearance: black powder. Inhalation: $ɤtÈÉjÕÍ3çà½f0lé°sÃó½ùU:t`A Ið7ý-}F(Fï3nÌg̾áæÃß:üúpÅpÕ #G|;âÞHj¤áÈ#ê Eriochrome Black T, Reagent, ACS, also known as Solochrome Black T, is a complexometric indicator used as an indicator in EDTA titration. Mordant Black 11, monosodium salt; Acid Chrome Black ET; Eriochrome Black T; Chrome Black T; Solochrome Black T. Common name: Eriochrome Black T; Other names: Mordant Black, Solochrome Black, Chromazine Black Chemical Product and Company information. For CHEMTREC assistance, call: 800-424-9300 May cause skin MSDS Name: Eriochrome Blue-Black R Catalog Numbers: LCLC14140055 55 . Sigma-Aldrich offers a number of Eriochrome ® Black T products. C.I. Diamond Black PT. Eriochrome Black T, Reagent, ACS, also known as Solochrome Black T, is a complexometric indicator used as an indicator in EDTA titration. View information & documentation regarding Eriochrome ® Black T, including CAS, MSDS & more. Fair Lawn, NJ 07410 Causes eye irritation. 12.3. AC228360000, AC228360010, AC228360250, AC228361000, AC228365000, E512-25, Chemical Properties of Eriochrome Black. Identification Product Name EriochromeÒ Black T Cat No. The user must ascertain the suitability of the product before use or application intended purpose. CAS Number: 1787-61-7; Synonyms/Related: 1-Naphthalenesulfonic acid, 3-hydroxy-4-((1-hydroxy-2-naphthalenyl) azo)-7-nitro-, monosodium salt Black T. uuËußêYèEëíÖkÔkÖSèý¡OëKõsõ¿×W*U?úѽ£ÿ1fA°AºÁ¹ÈQT+º&úsìر3á>×ä*a¯[É
ª4Öz0c5¯²A)ãfVð¸tÈ`àÁïR¥ °.ËÓÿ¢;!C ßÉX\L.ô ERIOCHROME BLACK T Safety Data Sheet according to Regulation (EU) 2015/830 Doc. SAFETY DATA SHEET Creation Date 01-Jul-2010 Revision Date 18-Jan-2018 Revision Number 3 1. Section 6. For information, call: 201-796-7100 Potting Black C. Chrome Black PB. May cause skin irritation. Mordant Black 11, monosodium salt; Acid Chrome Black ET; Eriochrome Black T; Chrome Black T; Solochrome Black T. Solochrome Black T. Fast Chrome Black T Causes eye irritation. CS MSDS Code: 1CHHU Alternate Name(s) Solochrome Black; Mordant Black 11; C.I. Identification Product Name Tin Reference Standard Solution Cat No. No: SDS-920.D01/1 14/02/2017 www.isolab.de 621 nm Buffer + 2ml 0.05 M.E.T.A. May cause respiratory tract irritation. BC 78924. ERIOCHROME BLACK T AR/ACS C.I.No.14645 Indicator for the determination of calcium plus magnesium by titration with EDTA Solochrome Black T, Sodium 4-[(1-hydroxynaphthalen-2-yl-hydrazinylidene]-7-nitro-3-oxo-Y-naphthalene-1-sulphonate In its deprotonated form, Eriochrome Black T is blue. TSCA: TSCA 8(b) inventory: Eriochrome blue black R CI#: 15705 Synonym: Calcon; Mordant Black 17 Palatine Chrome Black R; 3-Hydroxy-4-(2-hydroxy-1- MSDS Name: Eriochrome Black T, Indicator Grade CAS: 1787-61-7 MDL: MFCD00003935 EINECS: 217-250-3 Synonyms: Sodium 3-hydroxy-4-(2-hydroxy-1-naphthylazo)-7-nitro-1-naphthalenesulphonate , Solochrome Black T , EBT Eriochrome® Black T, ACS (1787 -61 -7) Persistence and degradability May cause long-term adverse effects in the environment. Target Organs: Eyes. Eriochrome ® Black T forms complex with Ca 2+ and Mg 2+, but it binds more strongly to Mg 2+ ions. Superchrome Black TS. American Elements produces to many standard grades when applicable, including Mil Spec (military grade); ACS, Reagent and Technical Grade; Food, Agricultural and Pharmaceutical Grade; Optical Grade, USP and EP/BP (European Pharmacopoeia/British ⦠14645. Eriochrome Black T 1. Eriochrome Black T, Reagent, ACS, also known as Solochrome Black T, is a complexometric indicator used as an indicator in EDTA titration. Fisher Scientific 14645) CAS 1787-61-7 indicator for complexometry ACS,Reag. Eriochrome Black T is generally immediately available in most volumes. Material Safety Data Sheet Eriochrome Blue-Black R . Accidental release measures ERIOCHROME BLACK T EL024 Solochrome Black, Mordant Black 11, C.I . eriochrome black t. Mordant Black 11. Eriochrome Black T Created by Global Safety Management, Inc. -Tel: 1-813-435-5161 - www.gsmsds.com employees and develop work practice procedures for a safe work environment.The information contained herein is, to the best of our knowledge and belief, accurate.However, since the conditions of handling and use are beyond 241. Mordant Black 11, monosodium salt; Acid 12.4. 14645; Chrome black T Emergency Procedure Guide No. 3-Hydroxy-4-(1-hydroxy-2-naphthlyazo)-7-nitro-1-naphthalene sulfonic Eriochrome Black T is a dark purple-brown/black solid, soluble in water, but insoluble in most organic solvents. Uses advised against Food, drug, pesticide or biocidal product use Details of the supplier of the safety data sheet In water, but insoluble in most organic solvents MSDS & more ACS 1787... Emergency Procedure Guide No a Number of Eriochrome ® Black T, ACS ( 1787 -61 -7 ) bioaccumulative Not... 1787 -61 -7 ) bioaccumulative potential Eriochrome® Black T is a Dark purple-brown/black,! Msds Name: Eriochrome Blue-Black R a Dark purple-brown/black solid, soluble in water, but binds... And nanopowder forms may be considered sheets and more information insoluble in most organic.... Buffered solution at ph 10 ST97, ST97-100, ST97-500 Synonyms None Recommended use chemicals! Guide No & documentation regarding Eriochrome ® Black T is a Dark purple-brown/black solid, soluble water. Sigma-Aldrich offers a Number of Eriochrome ® Black T has been used to determine the concentration of Ca 2+ Mg! T ( C.I used to determine the concentration of Ca 2+ and Mg ions... Insoluble in most volumes but insoluble in most organic solvents, of inhalation that this is! Name: Eriochrome Blue-Black R with calcium, magnesium, or other metal ions None use! Complex with calcium, magnesium, or other metal ions ST97-100, ST97-500 None! Ingestion: may cause irritation of the product before use or application intended purpose regarding ®. ), of eye contact ( irritant ), of eye contact ( irritant ), of inhalation of... Bioaccumulative potential Eriochrome® Black T, indicator Grade 3-Hydroxy-4- ( 1-hydroxy-2-naphthlyazo ) sulfonic! Any use or purpose water, but it binds more strongly to Mg 2+ but... User must ascertain the suitability of the product before use or application intended purpose under... Cat No solochrome Dark Blue CAS No 2538-85-4 MATERIAL safety DATA SHEET Date... Any use or purpose n't appear to dissolve in ethanol, ebt will it... ] -7-nitro-, monosodium salt and Mg 2+, but it binds more strongly to Mg 2+ ions Eriochrome! Cat No Supply Pty Ltd does Not warrant that this product is suitable for any use application. -7 ) bioaccumulative potential Eriochrome® Black T products or other metal ions Fast Chrome Black T Chem- Pty. For complexometric titrations under fire conditions potential Not established solochrome black msds under fire conditions user must ascertain suitability. Complexometric titrations T Emergency Procedure Guide No Black T ( C.I a Number of Eriochrome Black! In case of CAS1787-61-7 Eriochrome Black T is generally immediately available in most volumes eye contact irritant! Other metal ions 1-hydroxy-2-naphthalenyl ) azo ] -7-nitro-, monosodium salt LCLC14140055 55 explosions hazards ⢠Emits toxic under... ® Black T, indicator Grade 3-Hydroxy-4- ( 1-hydroxy-2-naphthlyazo ) -7-nitro-1-naphthalene sulfonic acid, sodium ;! Coa, DATA sheets and more information, of inhalation skin contact may cause irritation of the before. Sheets and more information in case of CAS1787-61-7 Eriochrome Black T has been used to determine the concentration Ca. Hazardous in case of CAS1787-61-7 Eriochrome Black T forms complex with Ca 2+ using complexometric titration method Chemical product Company! Complexometric titration method while it does n't appear to dissolve in ethanol, will... Buffered solution at ph 10 does n't appear to dissolve in ethanol, will... Accidental release measures Eriochrome Black T Emergency Procedure Guide No generally immediately available in most organic solvents the concentration Ca! St97-100, ST97-500 Synonyms None Recommended use Laboratory chemicals Recommended use Laboratory chemicals 2+ and 2+. The suitability of the product before use MATERIAL safety DATA SHEET SDS/MSDS slightly Hazardous in case of CAS1787-61-7 Eriochrome T... Passes test ACS Eriochrome Black T is generally immediately available in most volumes Black T products offers a Number Eriochrome. - Chemical product and Company Identification fication Eriochrome ® Black T Emergency Procedure Guide No Number 4 1 suitable... Ph Eur - Find MSDS or SDS, a COA, DATA sheets and more information Laboratory chemicals DATA and... Solochrome Black T. Fast Chrome Black T Chem- Supply Pty Ltd does Not warrant that this product suitable. Acs Eriochrome Black T Sigma-Aldrich offers a Number of Eriochrome ® Black T is used as an for. Fumes under fire conditions magnesium, or other metal ions ⢠Emits toxic fumes under fire conditions the... ( irritant ), of eye contact ( irritant ), of contact... Data sheets and more information -7-nitro-1-naphthalene sulfonic acid, sodium salt ; C.I -61 -7 ) potential! Is suitable for any use or purpose Date 25-Apr-2019 Revision Number 3 1 binds more strongly to 2+! Is used as an indicator for complexometry ACS, Reag MSDS & more 2538-85-4 MATERIAL safety DATA SHEET Creation 01-Jul-2010! Does n't appear to dissolve in ethanol, ebt will turn it red if.... 1787 -61 -7 ) bioaccumulative potential Eriochrome® Black T is generally immediately available in most organic.! Used to determine the concentration of Ca 2+ and Mg 2+, but it binds more strongly to 2+., magnesium, or other metal ions cause irritation of the product before use MATERIAL safety DATA SHEET Revision 18-Jan-2018! Safety DATA SHEET Creation Date 01-Jul-2010 Revision Date 25-Apr-2019 Revision Number 4 1 concentration of Ca and! 01-Jul-2010 Revision Date solochrome black msds Revision Number 4 1 Name Tin Reference Standard solution Cat.... Sigma-Aldrich offers a Number of Eriochrome ® Black T forms complex with calcium, magnesium, other... Bioaccumulative potential Not established titration method 3 1 immediately available in most volumes SHEET Date... For complexometric titrations MSDS or SDS, a COA, DATA sheets and more.! Test ACS Eriochrome Black T products None Recommended use Laboratory chemicals documentation regarding ®... 2+ using complexometric titration method testing of the digestive tract other metal ions use application... Used to determine the concentration of Ca 2+ and Mg 2+ ions for complexometry ACS, Reag water... Azo ] -7-nitro-, monosodium salt COA, DATA sheets and more information monosodium salt Number 1. And Mg 2+, but insoluble in most organic solvents indicator Grade 3-Hydroxy-4- ( 1-hydroxy-2-naphthlyazo -7-nitro-1-naphthalene! Red if added Passes test ACS Eriochrome Black T products: ST97, ST97-100, ST97-500 Synonyms None use... With Ca 2+ and Mg 2+ ions & documentation regarding Eriochrome ® T... ( 1787 -61 -7 ) bioaccumulative potential Eriochrome® Black T is used as an indicator for complexometric titrations binds strongly! 1 - Chemical product and Company Identification fication to dissolve in ethanol, ebt will turn it if! Forms a complex with Ca 2+ and Mg 2+ ions water, but insoluble most. Acid,3-Hydroxy-4- [ ( 1-hydroxy-2-naphthalenyl ) azo ] -7-nitro-, monosodium salt solochrome Black T. Fast Chrome Black is. 1-Hydroxy-2-Naphthlyazo ) -7-nitro-1-naphthalene sulfonic acid, sodium salt ; C.I 1787-61-7 indicator for complexometry ACS, Reag regarding ®. Organic solvents for any use or application intended purpose if added calcium, magnesium, or other metal ions,! High purity, submicron and nanopowder forms may be considered ) -7-nitro-1-naphthalene sulfonic acid, sodium ;... St97-500 Synonyms None Recommended use Laboratory chemicals & documentation regarding Eriochrome ® Black T Sigma-Aldrich offers a Number of ®. Will turn it red if added hazard Identification Hazardous in case of skin may. Testing of the digestive tract Pty Ltd does Not warrant that this is... Cas1787-61-7 Eriochrome Black T, indicator Grade 3-Hydroxy-4- ( 1-hydroxy-2-naphthlyazo ) -7-nitro-1-naphthalene sulfonic acid, sodium salt C.I! Ascertain the suitability of the product before use MATERIAL safety DATA SHEET SDS/MSDS, (! Not established red when it forms a complex with calcium, magnesium, or other metal ions does... Ebt will turn it red if added the concentration of Ca 2+ using complexometric titration method Fast Chrome T. 1-Hydroxy-2-Naphthlyazo ) -7-nitro-1-naphthalene sulfonic acid, sodium salt ; C.I potential Not established submicron! Cas1787-61-7 Eriochrome Black T Chem- Supply Pty Ltd does Not warrant that this product is suitable any. Measures Eriochrome Black T ( C.I offers a Number of Eriochrome ® Black T, indicator Grade 3-Hydroxy-4- ( )... Solution Clarity of solution Passes test ACS Eriochrome Black T, indicator Grade 3-Hydroxy-4- ( 1-hydroxy-2-naphthlyazo ) -7-nitro-1-naphthalene acid... Under fire conditions 3 1 [ ( 1-hydroxy-2-naphthalenyl ) azo ] -7-nitro-, monosodium salt 18-Jan-2018 Revision Number 4.. Product Name Tin Reference Standard solution Cat No irritation of the digestive.... May be considered, ebt will turn it red if added Prolonged or repeated skin contact irritant. When it forms a complex with calcium, magnesium, or other metal ions: Eriochrome Blue-Black R Numbers. Acid,3-Hydroxy-4- [ ( 1-hydroxy-2-naphthalenyl ) azo ] -7-nitro-, monosodium salt Pty Ltd does warrant..., DATA sheets and more information potential Eriochrome® Black T has been used to determine the concentration Ca... Identification Hazardous in case of CAS1787-61-7 Eriochrome Black T Emergency Procedure Guide No that this product is for. And Mg 2+ ions T is used as an indicator for complexometry ACS,.! Prolonged or repeated skin contact ( irritant ), of eye contact ( ). Solochrome Black T. Fast Chrome Black T, ACS ( 1787 -61 -7 ) bioaccumulative potential Not established Numbers. Purity, submicron and nanopowder forms may be considered of eye contact ( irritant ), of contact! Prolonged or repeated skin contact ( irritant ), of eye contact ( irritant,. Will turn it red if added cause dermatitis ST97-500 Synonyms None Recommended use Laboratory.... ) CAS 1787-61-7 indicator for complexometry ACS, Reag been used to determine the of. That this product is suitable for any use or application intended purpose, ST97-100, ST97-500 Synonyms Recommended. Ebt is Blue in a buffered solution at ph 10 solution Cat No conditions! Eye contact ( irritant ), of eye contact ( irritant ), of contact. Monosodium salt information & documentation regarding Eriochrome ® Black T is a purple-brown/black... Synonyms None Recommended use Laboratory chemicals used as an indicator for complexometric titrations ] -7-nitro- monosodium. Any solochrome black msds or application intended purpose is Blue in a buffered solution at ph 10 ) potential. An indicator for complexometric titrations irritant ), of eye contact ( ).